Service Manual: Variable Refrigerant Flow Outdoor Units 2 To 5 Tons

SERVICE MANUAL
Variable Refrigerant Flow Outdoor Units

2 to 5 Tons
PROPRIETARY DATA NOTICE
This document, as well as all reports, illustrations, data, information,
and other materials are the property of LG Electronics U.S.A., Inc., and are
disclosed by LG Electronics U.S.A., Inc. only in confidence.
Do not throw away, destroy, or lose this manual.

Please read carefully and store in a safe place for future reference.
Content familiarity is required for proper installation.
The instructions included in this manual must be followed to prevent product malfunction, property damage, injury, or death to the user or
other people. Incorrect operation due to ignoring any instructions will cause harm or damage. The level of seriousness is classified by the
symbols described by the summary list of safety precautions on page 4.
For more technical materials such as submittals, catalogs, engineering,

installation, best practices, and owner’s manuals, visit www.lghvac.com.
For continual product development, LG Electronics U.S.A., Inc. reserves the right to change specifications without notice.
© LG Electronics U.S.A., Inc.
TABLE OF CONTENTS
Safety Precautions ............................................................................. 4-7 Troubleshooting Main Components ............................................. 76-86

Test Run ............................................................................................ 76
Nomenclature......................................................................................... 8 Main Component Errors .................................................................... 77
Self Diagnostics Check...................................................................... 78
Wiring Diagrams ............................................................................... 9-12
Checking the Compressor ............................................................ 79-80
Refrigerant Flow Diagrams ............................................................ 13-26 Checking the Outdoor Unit Fan Motor ............................................... 80
Checking the Electronic Expansion Valves................................... 81-83
Outdoor Unit Functions ................................................................. 27-52 Checking the Inverter IPM / IGBT................................................. 84-85
Basic Control ................................................................................ 27-28 Checking the High / Low Pressure Sensors ..................................... 85
Normal Operation/Compressor Control ......................................... 27 Checking the Outdoor Fan ................................................................ 86
EEV Control ................................................................................... 28 Checking the Four-Way Reverse Valve ............................................. 86
Special Control ............................................................................. 29-31 Checking the Temperature Sensors .................................................. 88
Oil Return Control .......................................................................... 29
Defrost Control .............................................................................. 30 Error Codes ................................................................................... 87-152
Stop Operation .............................................................................. 31 Error Code General Information ........................................................ 87
Protection Control ......................................................................... 32-35 Error Code Tables ......................................................................... 88-93
Pressure Protection Control ..................................................... 32-33 Error Codes ................................................................................ 94-143
Discharge Temperature/Inverter Protection/ Replacing the Inverter PCB Heat Sink ............................................ 144
Pressure Switch........................................................................ 34-35 Checking the Phase Diode Bridge................................................... 145
Other Controls .............................................................................. 36-39 Checking Input Voltage in Case of Power On ................................. 146
Initial Setup ............................................................................... 36-39 Checking ODU to ODU Comm. (DC Voltage) in
Setting Optional Modes ................................................................ 40-52 Case of Power On ......................................................................... 147
Checking Inverter PCB in Case of Power Off ........................... 148-150
Heat Recovery Units....................................................................... 53-60 Checking Main PCB in Case of Power Off ...................................... 151
Parts Functions.................................................................................. 53 PCB Locations ................................................................................. 152
Dimensional Diagrams ................................................................. 54-56
Wiring Diagram .................................................................................. 57 Parts............................................................................................. 153-166
Refrigerant Circuit Diagram ............................................................... 58 PCBs ........................................................................................ 153-155
Functions ...................................................................................... 59-60 Control Box ............................................................................... 156-158
Expanded Frame View ............................................................. 159-161
PCB Settings ................................................................................... 61-75 Expanded Piping View .............................................................. 162-165
Heat Recovery Unit Settings ........................................................ 61-66
Indoor Unit Addressing ................................................................. 67-69
Pipe Detection Addressing ........................................................... 70-75
Due to our policy of continuous product innovation, some specifications may change without notification. 3
©LG Electronics U.S.A., Inc., Englewood Cliffs, NJ. All rights reserved. “LG” is a registered trademark of LG Corp.
SAFETY PRECAUTIONS
The instructions below must be followed to prevent product malfunction, property damage, injury or death to the user or other people. Incor-
rect operation due to ignoring any instructions will cause harm or damage. The level of seriousness is classified by the symbols described
below.
TABLE OF SYMBOLS
DANGER This symbol indicates an imminently hazardous situation which, if not avoided, will result in death or serious injury.
This symbol indicates a potentially hazardous situation which, if not avoided, could result in death or serious injury.
CAUTION This symbol indicates a potentially hazardous situation which, if not avoided, may result in minor or moderate injury.
This symbol indicates situations that may result in equipment or property damage accidents only.
MULTI V S Outdoor Unit Service Manual
This symbol indicates an action that must not be performed.
INSTALLATION
DANGER
'RQRWVWRUHRUXVHÀDPPDEOHJDVRUFRPEXVWLEOHVQHDU Do not supply power to the unit until all wiring and piping
the unit. are completed or reconnected and checked.
7KHUHLVULVNRI¿UHH[SORVLRQDQGSK\VLFDOLQMXU\RUGHDWK There is risk of physical injury or death due to electric shock.
Do not install or remove the unit by yourself (end user). If the air conditioner is installed in a small space, take
Ask the dealer or an authorized technician to install the unit. measures to prevent the refrigerant concentration from
,PSURSHULQVWDOODWLRQE\WKHXVHUZLOOUHVXOWLQ¿UHH[SORVLRQHOHFWULF exceeding safety limits in the event of a refrigerant leak.
shock, physical injury or death. Consult the latest edition of ASHRAE (American Society of Heating,
Refrigerating, and Air Conditioning Engineers) Standard 15. If the
For replacement of an installed unit, always contact an LG refrigerant leaks and safety limits are exceeded, it could result in person-
trained service provider. al injuries or death from oxygen depletion.
7KHUHLVULVNRI¿UHHOHFWULFVKRFNH[SORVLRQDQGSK\VLFDOLQMXU\RU
death. The heat recovery unit must be installed indoors; do not
install the heat recovery unit in a highly humid environment.
Wear protective gloves when handling equipment. Sharp There is risk of physical injury or death due to electric shock.
edges will cause personal injury.
Dispose the packing materials safely.
Do not change the settings of the protection devices. • Packing materials, such as nails and other metal or wooden parts,
If the protection devices have been bypassed or are forced to operate will cause puncture wounds or other injuries.
LPSURSHUO\RUSDUWVRWKHUWKDQWKRVHVSHFL¿HGE\/*DUHXVHGWKHUHLV • Tear apart and throw away plastic packaging bags so that children
ULVNRI¿UHHOHFWULFVKRFNH[SORVLRQDQGSK\VLFDOLQMXU\RUGHDWK will not play with them and risk suffocation and death.
Replace all control box and panel covers. Install the unit considering the potential for strong winds or
If cover panels are not installed securely, dust, water and animals will earthquakes.
HQWHUWKHRXWGRRUXQLWFDXVLQJ¿UHHOHFWULFVKRFNDQGSK\VLFDOLQMXU\RU Improper installation will cause the unit to fall over, resulting in physical
death. injury or death.
Always check for system refrigerant leaks after the unit has Install the unit in a safe location where nobody can step, fall
been installed or serviced. onto it, or place objects on it. Do not install the unit on a
Exposure to high concentration levels of refrigerant gas will lead to defective stand.
illness or death. It will result in an accident that causes physical injury or death.
Periodically check that the outdoor frame is not damaged.

There is a risk of explosion, physical injury, or death.
Due to our policy of continuous product innovation, some specifications may change without notification.
4
SAFETY PRECAUTIONS
Properly insulate all cold surfaces to prevent “sweating.”

Cold surfaces such as uninsulated piping can generate condensate that could drip, causing a slippery surface that creates a risk of slipping, falling,
and personal injury.
CAUTION
Be very careful when transporting the product. There is a risk of the product falling and causing physical injury.
• Use appropriate moving equipment to transport each frame; ensure the equipment is capable of supporting the weights listed.
• Some products use polypropylene bands for packaging. Do not use polypropylene bands to lift the unit.
• Suspend the outdoor unit from the base at specified positions (at a minimum of six [6] points) to avoid slippage from rigging apparatus.
LG Electronics U.S.A.,Inc., is not responsible for any piping Keep the unit upright during installation to avoid vibration or
calculations, refrigerant leaks, degradation of performance, water leakage.
or any other potential problems or damages as a result of
interconnecting piping, their joint connections, isolation When installing the unit in a hospital, mechanical room, or
Safety Precautions
valves, introduced debris inside the piping system, or other VLPLODUHOHFWURPDJQHWLF¿HOG(0)VHQVLWLYHHQYLURQPHQW
problems caused by the interconnecting piping system. SURYLGHVXႈFLHQWSURWHFWLRQDJDLQVWHOHFWULFDOQRLVH
Inverter equipment, power generators, high-frequency medical equip-
Do not install the product where it is exposed directly to ment or radio communication equipment will cause the air conditioner to
ocean winds. operate improperly. The unit will also affect such equipment by creating
Sea salt in the air will cause the product to corrode. Corrosion, par- electrical noise that disturbs medical treatment or image broadcasting.
WLFXODUO\RQWKHFRQGHQVHUDQGHYDSRUDWRU¿QVFRXOGFDXVHSURGXFW
PDOIXQFWLRQRULQHI¿FLHQWRSHUDWLRQ The heat recovery box must be installed indoors; do not
install the heat recovery box in a highly humid environment.
When installing the outdoor unit in a low-lying area, or a lo- There is risk of product failure and property damage.
cation that is not level, use a raised concrete pad or concrete
blocks to provide a solid, level foundation. When connecting refrigerant piping, remember to allow for
This prevents water damage and abnormal vibration. pipe expansion.
Improper piping will cause system malfunction.
Properly insulate all cold surfaces to prevent “sweating.”
Cold surfaces such as uninsulated piping can generate condensate that Do not install the outdoor unit or heat recovery unit in a
will drip and cause a slippery surface condition and / or water damage noise-sensitive area.
to walls.
Take appropriate actions at the end of HVAC equipment life
Always check for system refrigerant leaks after the unit has to recover, recycle, reclaim or destroy R410A refrigerant
been installed or serviced. according to applicable U.S. Environmental Protection
Low refrigerant levels will cause product failure. Agency (EPA) rules.
Do not make refrigerant substitutions. Use R410A only. Periodically check that the outdoor frame is not damaged.
If a different refrigerant is used, or air mixes with original refrigerant, the There is a risk of equipment damage.
unit will malfunction and be damaged.
Install the unit in a safe location where nobody can step on
'RQRWVWRUHRUXVHÀDPPDEOHJDVFRPEXVWLEOHVQHDU or fall onto it. Do not install the unit on a defective stand.
the unit. There is a risk of unit and property damage.
There is a risk of product failure.
Install the drain hose to ensure adequate drainage.
Do not use the product for mission critical or special pur- There is a risk of water leakage and property damage.
pose applications such as preserving foods, works of art, or
other precision air conditioning applications. The equipment
is designed to provide comfort cooling and heating.
There is risk of property damage.
SAFETY PRECAUTIONS
WIRING
DANGER
High voltage electricity is required to operate this system. Properly size all circuit breakers or fuses.
Adhere to the U.S. National Electric Code NEC and these 7KHUHLVULVNRI¿UHHOHFWULFVKRFNH[SORVLRQSK\VLFDOLQMXU\RUGHDWK
instructions when wiring.
Improper connections and inadequate grounding can cause accidental Do not share the electrical circuit with other devices.
injury or death. 7KHUHLVULVNRI¿UHHOHFWULFVKRFNDQGSK\VLFDOLQMXU\RUGHDWKGXHWR
heat generation.
Always ground the unit following local, state, and NEC codes.
7KHUHLVULVNRI¿UHHOHFWULFVKRFNDQGSK\VLFDOLQMXU\RUGHDWK Do not use damaged or loose power wiring. Do not
modify or extend the outdoor unit’s power wiring randomly.
7XUQWKHSRZHURႇDWWKHQHDUHVWGLVFRQQHFWEHIRUHVHUYLFLQJ Ensure that the power wiring will not be pulled nor weight be
the equipment. placed on the power wiring during operation.

Electrical shock can cause physical injury or death. 7KHUHLVULVNRI¿UHHOHFWULFVKRFNDQGSK\VLFDOLQMXU\RUGHDWK
The information contained in this manual is intended for use 6HFXUHDOO¿HOGZLULQJFRQQHFWLRQVZLWKDSSURSULDWHZLUH

E\DQLQGXVWU\TXDOL¿HGH[SHULHQFHGFHUWL¿HGHOHFWULFLDQ strain relief.
familiar with the NEC who is equipped with the proper tools Improperly securing wires will create undue stress on equipment power
and test instruments. OXJV,QDGHTXDWHFRQQHFWLRQVZLOOJHQHUDWHKHDWFDXVHD¿UHDQG
Failure to carefully read and follow all instructions in this manual can physical injury or death.
result in personal injury or death.
Ensure the system is connected to a dedicated power source
All electric work must be performed by a licensed electrician that provides adequate power.
and conform to local building codes or, in the absence of If the power source capacity is inadequate or the electric work is not
local codes, with the NEC, and the instructions given in this SHUIRUPHGSURSHUO\LWZLOOUHVXOWLQ¿UHHOHFWULFVKRFNSK\VLFDOLQMXU\RU
manual. death.
If the power source capacity is inadequate or the electric work is not
SHUIRUPHGSURSHUO\LWZLOOUHVXOWLQ¿UHHOHFWULFVKRFNSK\VLFDOLQMXU\RU Properly tighten all power connections.
death. /RRVHZLULQJZLOORYHUKHDWDWFRQQHFWLRQSRLQWVFDXVLQJD¿UHSK\VLFDO
injury or death.
Refer to local, state, and federal codes, and use power wires
RIVXႈFLHQWFXUUHQWFDSDFLW\DQGUDWLQJ Do not change the settings of the protection devices.
:LUHVWKDWDUHWRRVPDOOZLOOJHQHUDWHKHDWDQGFDXVHD¿UHDQGSK\VLFDO If the protection devices have been bypassed or is forced to operate
injury or death. LPSURSHUO\RUSDUWVRWKHUWKDQWKRVHVSHFL¿HGE\/*DUHXVHGWKHUHLV
ULVNRI¿UHHOHFWULFVKRFNH[SORVLRQDQGSK\VLFDOLQMXU\RUGHDWK
Do not supply power to the unit until all electrical wiring, The information contained in this manual is intended for use
controls wiring, piping, installation, and refrigerant system E\DQLQGXVWU\TXDOL¿HGH[SHULHQFHGFHUWL¿HGHOHFWULFLDQ
evacuation are completed. familiar with the NEC who is equipped with the proper tools
The system will malfunction. and test instruments.
Failure to carefully read and follow all instructions in this manual can
result in equipment malfunction and property damage.
6
SAFETY PRECAUTIONS
OPERATION
DANGER
'RQRWSURYLGHSRZHUWRRURSHUDWHWKHXQLWLILWLVÀRRGHG Use inert (nitrogen) gas when performing leak tests or air
or submerged. purges. 'RQRWXVHFRPSUHVVHGDLUR[\JHQRUÀDPPDEOH
7KHUHLVULVNRI¿UHHOHFWULFVKRFNSK\VLFDOLQMXU\RUGHDWK gases.
8VLQJWKHVHVXEVWDQFHVZLOOFDXVH¿UHH[SORVLRQDQGSK\VLFDOLQMXU\RU
Use a dedicated breaker for this product. death.
7KHUHLVULVNRI¿UHHOHFWULFVKRFNSK\VLFDOLQMXU\RUGHDWK
If refrigerant leaks out, ventilate the area before operating the
Do not operate the disconnect switch with wet hands. unit.
7KHUHLVULVNRI¿UHHOHFWULFVKRFNSK\VLFDOLQMXU\RUGHDWK If the unit is mounted in an enclosed, low-lying, or poorly ventilated area,
DQGWKHV\VWHPGHYHORSVDUHIULJHUDQWOHDNLWZLOOFDXVHD¿UHHOHFWULF
Periodically verify the equipment mounts have not shock, explosion, physical injury or death.
deteriorated.
If the base collapses, the unit could fall and cause physical injury or death.
Do not allow water, dirt, or animals to enter the unit. Do not touch the refrigerant piping during or after opera-
7KHUHLVULVNRI¿UHHOHFWULFVKRFNSK\VLFDOLQMXU\RUGHDWK tion.
Safety Precautions
It can cause burns or frostbite.
Do not operate the unit with the panel(s) or protective
FRYHUVUHPRYHGNHHS¿QJHUVDQGFORWKLQJDZD\IURP Do not open the inlet during operation.
moving parts. There is risk of electric shock, physical injury or death.
The rotating, hot, cold, and high-voltage parts of the unit can cause
physical injury or death.
CAUTION
To avoid physical injury, use caution when cleaning or servicing the air conditioner.
There is risk of electric shock, physical injury or death.
&OHDQXSWKHVLWHDIWHUVHUYLFLQJLV¿QLVKHGDQGFKHFNWKDW Use only a soft cloth to clean the air conditioner. Do not
no metal scraps, screws, or bits of wiring have been left use wax, thinner, or strong detergents.
inside or surrounding the unit. Strong cleaning products will damage the surface of the air conditioner,
Do not use the product for mission critical or special pur- or will cause its appearance to deteriorate.
pose applications such as preserving foods, works of art, or Provide power to the outdoor unit to warn the compressor
other precision air conditioning applications. The equipment crankcase at least six (6) hours before operation begins.
is designed to provide comfort cooling and heating. Starting operation with a cold compressor sump(s) will result in severe
There is risk of property damage. bearing damage to the compressor(s). Keep the power switch on during
Do not allow water, dirt, or animals to enter the unit. the operational season.
There is risk of unit failure. 'RQRWWXUQRႇWKHPDLQSRZHUVZLWFKDIWHURSHUDWLRQKDV
Do not open the inlet during operation. been stopped.
There is risk of unit failure. :DLWDWOHDVW¿YHPLQXWHVEHIRUHWXUQLQJRIIWKHPDLQSRZHUVZLWFK
otherwise it will result in product malfunction.
Do not operate the unit with the panel(s) or protective
FRYHUVUHPRYHGNHHS¿QJHUVDQGFORWKLQJDZD\IURP Do not block the inlet or outlet.
moving parts. Unit will malfunction.
Non-secured covers can result in malfunction due to dust or water in the Auto-addressing must be performed after connecting the
service panel. power of all indoor and outdoor units.
Periodically verify the equipment mounts have not Auto-addressing must also be performed after servicing an indoor unit.
deteriorated.
If the base collapses, the unit could fall and cause property damage or
product failure.
UNIT NOMENCLATURE
Outdoor Units (ODU)
ARU N 038 G S S 4
Family
ARU = Multi V Outdoor Unit (Refrigerant R410A)
Type
B = Inverter Heat Recovery
N = Inverter Heat Pump
Capacity (Mbh)
024 = 24 053 = 53
038 = 38 060 = 60
048 = 48
Electrical Ratings
G = 208–230V/60Hz/1Ph
Type
S =Standard
Airflow Configuration
S = Side Discharge
Generation
4 = Fourth
Heat Recovery Units (HRU)

PRHR 02 2A
Family
PRHR = Multi V Heat Recovery (HR) unit (Refrigerant R410A)
Number of Ports
02 = Two Ports
03 = Three Ports
04 = Four Ports
Series Number
2A = Series Number
8
WIRING DIAGRAMS
Heat Pump Unit — ARUN024GSS4
Outdoor Unit Functions
WIRING DIAGRAMS
Heat Pump Units — ARUN038GSS4, ARUN048GSS4, ARUN053GSS4
10
WIRING DIAGRAMS
WIRING DIAGRAMS
Heat Recovery Unit — ARUB060GSS4
12
REFRIGERANT FLOW DIAGRAMS
Cooling Mode
Heating Mode
14
Oil Return / Defrost
Cooling Mode
Indoor Heat Exchanger Indoor Heat Exchanger

Electronic Electronic
Expansion Valve Flare Expansio n Valve Flare
Joint Joint
M M
Fan Flare Fa n Flare
Joint Joint
High Temperature High Pressure Vapor

High Temperature High Pressure Liquid
Low Temperature Low Pressure Vapor
Fan M Fan M
Outdoor
Temperature
Sensor
Charging
Port
Outdoor Unit
HEX Temperature 4-Way Valve
Sensor
Hot Vapor Vapor Pipe
Valve
Suction
ss
Temperature Liquid Pipe

Outdoor Sensor
EEV Oil
Separator Liquid Pipe
Temperature
Low Sensor
High Pressure
Switch Pressure
Sensor
High Pressure
Sensor
Comp. Discharge
Temperature
Sensor
Accumulator
Sub-cooling
Circuit Outlet Inverter Compressor
Temperature
Sensor
Sub-Cooler
Sub-Co o ling EEV Out doo r Unit
Press u re Sensor Temperature Sensor Check Valve Solenoid Va lv e

s
Remarks
Pressure Switch Service Valve EEV Strainer
16
Heating Mode

Electronic El ectr onic
Expansion Valv e Flare Expansion Valve Flare
Joint Joint
M M
Fan Flare Fan Flare
Joint Joint

Fan M Fan M

Outdoor
Temperature
Sensor Charging
Port
4-Way Valve
Outdoor Unit Hot Vapor Vapor Pipe

HEX Temperature Valve
Sensor Suction s
Sensor
Outdoor
EEV Liquid Pipe
Oil
Temperature
Separator
Sensor
High Pressure Low

Switch Pressure
Sensor
High Pressure
Sensor
Comp. Discharge
Temperature
Sensor
Sub-cooling Accumulator
Circuit Outlet
Temperature Inverter Compressor
Sensor
Sub-Cooler
Sub-Coo ling EE V Outdoor Unit
Press u re Sensor Temperature Sensor Check Valve Solenoid Valve

s
Remarks
Pr essure Switch Service Valve EEV Strainer

Electronic Electronic
Expansion Valve Flare Expansion Valve Flare
Joint Joint
M M
Fan Flare Fa n Flare
Joint Joint

Fan M Fan M Low Temperature Low Pressure Vapor
Outdoor
Temperature
Sensor
Charging
Port
Outdoor Unit
Hot Vapor Vapor Pipe
HEX Temperature
Valve
Sensor
Suction
s

Liquid Pipe
Outdoor Sensor
Temperature
EEV Oil Sensor
Separator
High Pressure Low

Switch Pressure
Sensor
High Pressure
Sensor
Comp. Discharge
Temperature
Sensor
Accumulator
Sub-cooling
Circuit Outlet Inverter Compressor
Temperature
Sensor
Sub-Cooler
Sub-Co o ling EE V Outdoor Unit
Pr ess u re Sensor Temperature Sensor Check Valve Sole noid Va lve

s
Remarks
Pressure Switch Service Valve EEV Strainer
18
Cooling Mode

Indoor HEX EEV Indoor HEX EEV
Fan Fan
Indoor Unit Indoor Unit
Fan Motor

M
4Way
Valve
M
Low
Outdoor Suction Pressure
Outdoor
Unit HEX Temperature Sensor
Temperature
Temperature Thermistor
Sensor
Sensor
High
Pressure
Pressure
Switch
Sensor
Strainer
Accumulator
Comp. Comp. Oil
Inv. Discharge Seperator
Temperature
Sensor
Outdoor EEV
Charging
Port
Strainer
Vapor Pipe
Sub-Cooling Circuit Liquid Pipe
Outlet Temperature Sensor Temperature Liquid Pipe
Sensor
Sub-Cooling Strainer
HEX
Heatsink
Sub-Cooling EEV
Pressure Sensor Temperature Sensor Check Valve Solenoid Valve

Remarks
Pressure Switch SVC Valve EEV Strainer
Heating Mode

Fan Fan

Fan Motor
M
4Way
Valve
M
Low
Outdoor
Temperature
Sensor
Sensor
High
Pressure
Pressure
Switch
Sensor
Strainer
Accumulator
Comp. Comp. Oil
Temperature
Charging Sensor
Outdoor EEV Port
Strainer
Vapor Pipe
Sensor
Sub-Cooling
HEX
Strainer
Heatsink
Sub-Cooling EEV

Remarks
20

Fan Fan
Fan Motor

M
4Way
Valve
M
Low
Outdoor
Temperature
Sensor
Sensor
High
Pressure
Pressure
Switch
Sensor
Strainer
Accumulator
Comp. Comp. Oil
Temperature
Sensor
Outdoor EEV
Charging
Port
Strainer
Vapor Pipe
Sensor
HEX
Heatsink
Sub-Cooling EEV

Remarks
Cooling Mode
Indoor HEX EEV High Temperature High Pressure Vapor

High Temperature High Pressure Liquid (Conditional)
Fan Low Temperature Low Pressure Vapor
Indoor Unit
HR unit
s s
Indoor HEX EEV s
s
s
Fan
s
Indoor Unit
s
s
s
Indoor HEX EEV

s
s
Fan s
Indoor Unit
s
Indoor HEX EEV
Fan
Indoor Unit
Fan Motor
M
4Way
Valve
M
Low
Outdoor
Temperature
Sensor
Sensor
High Charging
Pressure Port
Pressure
Switch
Sensor
Strainer
Accumulator
Comp. Comp. Oil
Temperature
Sensor
Outdoor EEV
Strainer Low Pressure

Vapor Pipe
Sensor
High Pressure
Vapor Pipe
HEX
Heatsink
Sub-Cooling EEV

Remarks
22
Heating Mode
Indoor HEX High Temperature High Pressure Vapor

EEV
Fan
Indoor Unit
HR unit
s s
Indoor HEX EEV s
s
s
Fan
s
Indoor Unit
s
s
s
Indoor HEX EEV

s
s
s
Fan

Indoor Unit
s
Indoor HEX EEV
Fan
Indoor Unit
Fan Motor
M
4Way
Valve
M
Low
Outdoor
Temperature
Sensor
Sensor
High Charging
Pressure Port
Pressure
Switch
Sensor
Strainer
Accumulator
Comp. Comp. Oil
Temperature
Sensor
Outdoor EEV

Vapor Pipe
Sensor
High Pressure
Vapor Pipe
HEX
Heatsink
Sub-Cooling EEV

Remarks
Cooling-Based Simultaneous Mode
Indoor HEX EEV High Temperature High Pressure Vapor

Indoor Unit
HR unit
s s
Indoor HEX EEV s
s
s
Fan
s
Indoor Unit
s
s
Indoor HEX EEV

s
s
s
Fan
Indoor Unit
s
Indoor HEX EEV
Fan
Indoor Unit
Fan Motor
M
4Way
Valve
M
Low
Outdoor
Temperature
Sensor
Sensor
High Charging
Pressure Port
Pressure
Switch
Sensor
Strainer
Accumulator
Comp. Comp. Oil
Temperature
Sensor
Outdoor EEV

Vapor Pipe
Sensor
High Pressure
Vapor Pipe
HEX
Heatsink
Sub-Cooling EEV

Remarks
24
Heating-Based Simultaneous Mode

Indoor HEX EEV
Indoor Unit
HR unit
s s
s
Indoor HEX EEV
s
s
Fan
s
Indoor Unit
s
s
s
Indoor HEX EEV

s
s
Fan s

Indoor Unit
s
Indoor HEX EEV
Fan
Indoor Unit
Fan Motor
M
4Way
Valve
M
Low
Outdoor
Temperature
Sensor
Sensor
High Charging
Pressure Port
Pressure
Switch
Sensor
Strainer
Accumulator
Comp. Comp. Oil
Temperature
Sensor
Outdoor EEV

Vapor Pipe
Sensor
High Pressure
Vapor Pipe
HEX
Heatsink
Sub-Cooling EEV

Remarks
Oil Return and Defrost

Indoor HEX EEV
Fan
Indoor Unit
HR unit
s s
Indoor HEX EEV s
s
s
Fan
s
Indoor Unit
s
s
Indoor HEX EEV

s
s
s
Fan
Indoor Unit
s
Indoor HEX EEV
Fan
Indoor Unit
Fan Motor
M
4Way
Valve
M
Low
Outdoor
Temperature
Sensor
Sensor
High Charging
Pressure Port
Pressure
Switch
Sensor
Strainer
Accumulator
Comp. Comp. Oil
Temperature
Sensor
Outdoor EEV

Vapor Pipe
Sensor
High Pressure
Vapor Pipe
HEX
Heatsink
Sub-Cooling EEV

Remarks
26
BASIC CONTROL
Normal Operation / Compressor Control
Normal Operation
Table 1: Normal Operation Functions.
Component Cooling Operation Heating Operation System Not in Operation
Compressor Fuzzy Logic Fuzzy Logic Stop
Fan Fuzzy Logic Fuzzy Logic Stop
Main EEV Fully Open Fuzzy Logic Close
One (1) 1 hour after Heating
Mode Stops and Outdoor
Four-Way Valve Off On
Temperature is > 86°F:
OFF
Subcooling EEV Fuzzy Logic Fuzzy Logic Close
Indoor Unit EEV Superheat Fuzzy Logic Subcool Fuzzy Logic Close

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• &RROLQJRSHUDWLRQZLOOQRWIXQFWLRQLIRXWGRRUDLUWHPSHUDWXUHLV)ZLWKDQLQGRRUXQLWFRPELQDWLRQLV
Compressor Control
Fuzzy logic helps ensure stable system performance by maintaining a constant evaporating temperature (Te) in cooling mode, and a constant
condensing temperature (Tc) in heating mode. Both Te (cooling) and Tc (heating) can be set at various steps in the installation mode.
• Cooling Mode (Te): 35.6~41°F
• Heating Mode (Tc): 116.6~123.8°F
Te and Tc can be determined simultaneously by setting DIP switches.
Figure 1: Fuzzy Logic Diagram. Figure 2: Inverter Linear Control Chart.

System Capacity
Fuzzy Logic Start

Target
(Linear Control)
Inverter
Compressor
Min. Frequency
Stop (0Hz)
Cooling and heating load

Fuzzy Logic
Inverter linear control as cooling and heating load increase
BASIC CONTROL
EEVs
EEV Control
Main EEV Control
Main EEV operates with fuzzy logic to keep the degree of superheat (about 37.4°F) at the evaporator outlet stable during heating mode.
Degree of Superheat = Tsuction - Tevaporation
where,
• Tsuction = Temperature measured at the suction pipe sensor (°F).
• Tevaporation = Evaporation temperature equivalent to low pressure (°F).
Subcooling EEV Control

Subcooling EEV operates with fuzzy logic to keep the degree of subcool (about 59°F) at the outlet of the subcooler stable during cooling
mode.
Degree of Subcool = Tcondensation - Tliquid

where,
• Tliquid = Temperature at the outlet of the subcooler (°F).
• Tcondensation = Condensation temperature equivalent to high pressure (°F).
Avoiding Excessively High Discharge Temperatures

After the main EEV opens to a predetermined amount, and the discharge temperature is above 185°F in heating mode, the subcooling EEV
will control the subcooling outlet temperature / evaporating temperature to some difference.
28
SPECIAL CONTROL
Oil Return Control
Oil Return Control

Oil return operation recovers any oil that has accumulated in the piping and returns it to the compressor. Each component operates as shown
in the tables below during oil return.
Oil Return in Cooling Mode

Table 2: Outdoor Unit Oil Return Control in Cooling Mode.
Component Start During Oil Return Operation Stop
Inverter Compressor 30Hz Set Value 30Hz
Fan Normal Control Normal Control Normal Control
Main EEV Maximum Pulse Maximum Pulse Maximum Pulse
Subcooling EEV Minimum Pulse Minimum Pulse Minimum Pulse
Four-Way Valve Off Off Off
Hot Gas Bypass Valve
(ARUN024~053GSS4 Heat Pump Normal Control Normal Control Normal Control
Units Only)

Table 3: Indoor Unit Oil Return Control in Cooling Mode.
Fan Normal Control Normal control Normal Control
Thermo On Unit EEV Normal Control Normal control Normal Control
Thermo Off Unit EEV 40 Pulse 400 Pulse 40 Pulse
Oil Return Signal Off On Off
• Start: Oil Return Operation will run every eight (8) hours.
• Oil Return Operation will run for three (3) minutes.
• Stop: Oil Return Operation will end if / when compressor protection control starts.
Oil Return Control in Heating Mode

Table 4: Outdoor Unit Oil Return Control in Heating Mode.
Fan Off Normal Control Off
Main EEV 300 Pulse Maximum Pulse 200 Pulse
Four-Way Valve On 2Qĺ2IIĺ2Q On
Units Only)
Table 5: Indoor Unit Oil Return Control in Heating Mode.

Thermo On Unit EEV Normal Control 400 ~ 800 Pulse 3XOVHĺ3XOVHĺ1RUPDO&RQWURO
Thermo Off Unit EEV 60 ~ 100 Pulse 400 ~ 800 Pulse 3XOVHĺ3XOVHĺa3XOVH
• Start: Oil Return Operation will run every eight (8) hours.
• Oil Return Operation will run for three (3) minutes.
• Stop: Oil Return Operation will end if / when compressor protection control starts.
SPECIAL CONTROL
Defrost Control
Defrost Control
Defrost Control eliminates ice that has accumulated on the heat exchanger, recovering its performance. Each component operates as shown
in the tables below during defrost.
Table 6: Outdoor Unit Defrost Control.
Component Start During Defrost Control Operation Stop
Fan Off Normal Control Off
Main EEV 300 Pulse Maximum Pulse 200 Pulse
Four-Way Valve On 2Qĺ2IIĺ2Q On

Units Only)
Table 7: Indoor Unit Defrost Control.

Component Start During Defrost Control Operation Stop
Thermo On Unit EEV Normal Control 400 ~ 800 Pulse 3XOVHĺ3XOVHĺ1RUPDO&RQWURO
Thermo Off Unit EEV 60 ~ 100 Pulse 400 ~ 800 Pulse 3XOVHĺ3XOVHĺa3XOVH
Defrost Control Stop Operation

1. All heat exchanger pipe temperatures are above set temperatures for thirty (30) seconds.
2. Defrost Control Operation will run for >30% of the total heating time.
3. Defrost Control Operation will stop if / when compressor protection control starts (if a high discharge temperature at the compressor is
detected).
30
SPECIAL CONTROL
Stop Operation
Stop Operation Control

Stop Operation Control in Cooling Mode
Table 8: Stop Operation Control in Cooling Mode.
Component Stop Operation Notes
Inverter Compressor 0 Hz -
Fan Stop -
Main EEV Minimum Pulse -
Subcooling EEV Minimum Pulse -
Four-Way Valve Off -
Hot Gas Bypass Valve (ARUN024~053GSS4 Heat Pump Units Only) Off After 15 Minutes (Before 15 Minutes: On)
Stop Operation Control in Heating Mode

Table 9: Stop Operation Control in Heating Mode.
Component Stop Operation Notes

Inverter Compressor 0 Hz -
Fan Stop -
Main EEV Minimum Pulse -
Subcooling EEV Minimum Pulse -
One (1) Hour After Stop and Outdoor
Four-Way Valve 2Qĺ2II
7HPSHUDWXUHLV!)ĺ2II
Hot Gas Bypass Valve (ARUN024~053GSS4 Heat Pump Units Only) Off After 15 Minutes (Before 15 Minutes: On)
PROTECTION CONTROL
Pressure Protection Control
Heat Pump Units — ARUN024 ~ 053GSS4

Pressure Control in Cooling Mode
Table 10: Compressor High Pressure Control in Cooling Mode. Table 11: Fan High Pressure Control in Cooling Mode.
Pressure Range Compressor Pressure Range Fan
3GSVL Stop 3GSVL Stop
3GSVL -5 Hz / 10 seconds 3GSVL +50 RPM / 10 seconds
3GSVL Frequency Hold* 3GSVL RPM Hold*
3GSVL +2 Hz or less / 10 seconds Pd < 518.9 psi Normal Control
Pd < 528.5 psi Normal Control
* Frequency Hold = Frequency (or RPM) is not increasing (can decrease).
Table 12: Low Pressure Control in Cooling Mode.

Pressure Range Compressor Fan
3VSVLRQH>@PLQXWHODWHU Stop
3VSVL -15 Hz / 10 seconds -100 RPM / 10 seconds
Pressure Control in Heating Mode

Table 13: High Pressure Control in Heating Mode.
Pd > 557.8 psi Stop
3GSVL -15 Hz / 10 seconds -50 RPM / 10 seconds
3GSVL Frequency Hold* -50 RPM / 10 seconds
3GSVL Frequency Hold* RPM Hold*
Table 14: Low Pressure Control in Heating Mode.

3VSVLRQH>@PLQXWHODWHU Stop
3VSVL -15 Hz / 10 seconds +100 RPM / 10 seconds
Ps > 31.3 psi Frequency Hold* +100 RPM / 10 seconds
3VSVL +2 Hz or less / 10 seconds +100 RPM / 10 seconds
3VSVL Normal Control
32
PROTECTION CONTROL
Heat Pump Unit — ARUN060GSS4, and Heat Recovery Unit — ARUB060GSS4

Pressure Control in Cooling Mode
Table 15: High Pressure Control in Cooling Mode.
3GSVL Stop
Pd > 547.5 psi -15 Hz / 10 seconds +100 RPM / 10 seconds
3GSVL Frequency Hold* RPM Hold*
3GSVL +2 Hz or less / 10 seconds RPM Hold*
Table 16: Low Pressure Control in Cooling Mode.

3VSVL 6WRSRQH>@PLQXWHODWHU Stop

3VSVL -10 Hz / 10 seconds -100 RPM / 10 seconds
Ps > 21.8 psi Frequency Hold* RPM Hold*
Ps > 26.8 psi +2 Hz or less / 20 seconds -100 RPM / 10 seconds
Ps > 31.9 psi +2 Hz or less / 10 seconds -100 RPM / 10 seconds
Ps > 37.7 psi Normal Control
Pressure Control in Heating Mode

Table 17: High Pressure Control in Heating Mode.
3GSVL Stop
Pd > 495.3 psi -15 Hz / 10 seconds -50 RPM / 10 seconds
Table 18: Low Pressure Control in Heating Mode.

3VSVL 6WRSRQH>@PLQXWHODWHU Stop
3VSVL -10 Hz / 10 seconds +100 RPM / 10 seconds
Ps > 21.8 psi Frequency Hold* RPM Hold*
3VSVL Normal Control
PROTECTION CONTROL
Discharge Temperature Control / Inverter Protection Control / Pressure Switch
Heat Pump Units — ARUN024 ~ 053GSS4
Discharge Temperature Control

Table 19: Outdoor Unit Discharge Temperature Control.
Temperature Range Compressor Subcooling EEV Indoor Unit EEV
7GLV) Off Minimum Pulse Minimum Pulse
Tdis > 230°F -5 Hz / 10 seconds SC, SH Decrease Control SH Decrease Control
Tdis < 230°F -5 Hz / 30 seconds SC, SH Decrease Control SH Decrease Control
7GLV) No Increase SC, SH Decrease Control SH Decrease Control
7GLV) +3 Hz or less SC, SH Decrease Control SH Decrease Control
Tdis > 212°F Normal Control SC, SH Decrease Control SH Decrease Control
Tdis = Temperature Discharge.
SC = Subcooling.
SH = Superheating.
Inverter Protection Control for ARUN038 ~ 053GSS4 Only

Table 20: Discharge Temperature Control in Cooling Mode.
Current Type Normal Operation Frequency Will Drop System Will Stop
AC Input Current 25A or less 27A or less 30A or less
Compressor Current 14A or less 15A or less 20A or less
Table 21: Discharge Temperature Control in Heating Mode.

Pressure Switch
• There is a pressure sensor switch in series between the compressor and the power relay.
• The pressure sensor switch is normally On.
The pressure sensor switch has small electric current from 220V AC. Never touch the connecting terminal nor short two wires. There is risk of
¿UHHOHFWULFVKRFNDQGSK\VLFDOLQMXU\RUGHDWK
34
PROTECTION CONTROL
Discharge Temperature Control / Inverter Protection Control / Pressure Switch
Heat Pump Unit — ARUN060GSS4, and Heat Recovery Unit — ARUB060GSS4
Discharge Temperature Control

Table 22: Outdoor Unit Discharge Temperature Control.
Temperature Range Compressor Subcooling EEV Indoor Unit EEV
Tdis > 235.4°F -5 Hz / 10 seconds SC, SH Decrease Control SH Decrease Control
Tdis > 230°F -5 Hz / 30 seconds SC, SH Decrease Control SH Decrease Control
7GLV) Frequency Hold SC, SH Decrease Control SH Decrease Control
7GLV) +3 Hz or less SC, SH Decrease Control SH Decrease Control
Tdis > 212°F Normal Control SC, SH Decrease Control SH Decrease Control
Tdis = Temperature Discharge.
SC = Subcooling.
SH = Superheating.
Inverter Protection Control

Table 23: Discharge Temperature Control in Cooling Mode.
Table 24: Discharge Temperature Control in Heating Mode.

Pressure Switch
• There is a pressure sensor switch in series between the compressor and the power relay.
• The pressure sensor switch is normally On.
The pressure sensor switch has small electric current from 220V AC. Never touch the connecting terminal nor short two wires. There is risk of
¿UHHOHFWULFVKRFNDQGSK\VLFDOLQMXU\RUGHDWK
OTHER CONTROLS
Initial Setup
Initial Setup
There are four (4) initial setup steps before operation can begin. All DIP switch settings must be completed before initial setup.
Step 1 Turn power on.

Factory set value is displayed on the PCB seven segment display (SSD) for
twenty-four (24) seconds. Code for the outdoor unit is displayed for
three (3) seconds. 07
Blank for six (6) seconds.

Total capacity is displayed for two (2)

seconds. 10
System type is displayed.
• Heat Pump = 2 is default value. 2
• Heat Recovery = 3 is default value.
Electrical requirements are displayed.
• 208-230V = 22 22
Model Type.
1
Step 2
Communication Check: If display follows all sequences as shown above, communication is normal. If the SSD shows Error Code 104*, check
the DIP switch settings and the communication cables on the outdoor unit.
Step 3
PCB Error Check: Error check will begin after forty (40) seconds.
36
OTHER CONTROLS
Initial Setup
Initial Setup, Continued.

Step 4: Indoor Unit Auto Addressing Procedure
Disconnects must only be operated by a properly licensed electrician at this time. Never look at a disconnect switch when closing. Turn away
from the switch when closing. Incorrect wiring could cause the disconnect to explode, physical injury, and / or death.
• Supply power to the indoor units. If power is not supplied, an operation error will occur.
• During the pre-commissioning process for systems with Gen 4 indoor units, do not change any DIP switch settings except for No. 3
on SW01B, which must be ON to enable Gen. 4 features. All other combinations of switches (one [1] through seven [7]) must be left in the
OFF position on the outdoor unit DIP switch bank SW01B. Refer to System Combinations and Outdoor Unit Operation Settings for proper
setting of No. 3 on SW01B.
• If the Auto Address Procedure has never been successfully completed for the system, the compressor(s) will not start when power is
applied to the unit.
• Auto addressing is only possible on the main PCB of the outdoor unit.

1. Verify all that all indoor units connected to the system have power to the PCB board AND all zone controller system start buttons are OFF.
2. Remove the maintenance access panel and unit control box cover from the outdoor unit. Place panels and screws in a secure area.
3. Verify that the communications cable between the indoor units and the outdoor unit is terminated at the outdoor unit terminals IDU(A) and
IDU (B).
4. Verify the shield on the communications cable is grounded at the outdoor unit.
5. Check if all DIP switches are set to OFF.
6. Cycle power on the outdoor units, indoor units, etc., and wait three (3) minutes while the outdoor unit sequences through the self-diagnos-
tics check, and to improve indoor unit communication when initial power is supplied. Leave disconnect in the “ON” position.
7. Check the outdoor unit(s) current configuration code(s). Observe the unit setup codes using the LED display found on the outdoor units
PCB. Each code will display for two (2) seconds.
After the self-diagnostics check is complete, the LED must be clear and nothing displayed. Diagnostic process must take from three (3) to seven (7)
minutes.
8. Know how many indoor units are connected to the system.
9. Press and hold the red SW01C button for about five (5) seconds. Release when “88” appears on the LED. After three (3) to seven (7)
minutes, the display will flash a number for about ten (10) to thirty (30) seconds indicating how many indoor units the system successfully
communicated with.
10. This number must match the known installed number of indoor units if the auto addressing procedure was successful. If using LGMV,
read the address of each indoor unit. The address of each indoor unit is also indicated on wired remote control displays.
11. Upon completion of the auto addressing routine, the display will be blank and the system will be in standby waiting for another com-
mand.
OTHER CONTROLS
Initial Setup
Initiate the Auto Addressing Procedure, continued. Figure 3: Auto Address Button Location on ARUN24~53GSS4 Outdoor
Unit PCB.
12. Upon successful completion of the auto address procedure,
record the system address assigned to each indoor unit by the auto DIP-Switch SW01 SSD
address procedure in the column provided on the Pre-commission-
ing Device Configuration Worksheet.
13. After recording the system addresses assigned to each device,

open the outdoor unit disconnect. Remove the outdoor unit to indoor
unit communications cable from terminals IDU(A) and IDU(B). Pro- SW04C ( &DQFHO
tect conductors by placing electrical tape over the bare ends.
SW03C ( )RUZDUG
14. Close the disconnect to reapply power to the outdoor unit and
energize the compressor crankcase heater. Once again, verify that SW02C ( %DFNZDUG
the outdoor unit to indoor unit(s) communications cable is not con-
SW01C ( &RQ¿UP
nected to terminals IDU(A) and IDU(B) of the outdoor unit.
6:'5HVHW
15. Replace the control panel door. Figure 4: Auto Address Button Location on ARUN60GSS4 and
ARUB60GSS4 Outdoor Unit PCB.
SSD
SW01C SW01D
( &RQ¿UP 5HVHW
Figure 5: Indoor Unit Auto Addressing Procedure Flowchart.
SW04C
SW02C ( &DQFHO
Turn Power On.
( %DFNZDUG DIP-Switch
SW01
Wait Three (3) Minutes.
SW03C
( )RUZDUG
Press and Hold Red SW01C

Button for Five (5) Seconds.
Upon successful completion of the auto address-

Automatic Addressing Begins.
LED Shows = 88 ing function, an unintentional compressor start
can occur unless the communications cable to
the indoor units is removed from the outdoor unit
Release Red SW01C Button.
terminals IDU(A) and IDU(B). Do NOT open
the service valves or attempt to start outdoor unit
Automatic Addressing Settings Ends. compressors or until directed by the LG trained
Numbers of indoor units with complete Commissioner. Major damage to the unit piping
Wait Two (2) to Seven (7) Minutes. addressing are displayed for thirty (30)
and compressors will occur, and there is a risk
seconds on the LED after setting is complete.
of explosion, suffocation, physical injury, and / or
death.
LED Shows = 88 NO Check Communications
Cable Connections.
YES
Indoor address number is shown on wired remote controller or on the indoor unit
display. This is not an error message, and will disappear when the ON / OFF button
is pressed on the remote controller. Example: Display of 01, 02... 15 indicates that
fifteen (15) indoor units are connected and the automatic addressing has been
Auto Addressing Successful. successfully completed.
38
OTHER CONTROLS
Initial Setup
Troubleshooting a Failed Indoor Unit Auto Addressing Procedure
If the quantity of indoor units the auto addressing procedure found is incorrect, or the “88” never disappears from the display for the seven (7)
minutes, the auto address routine has failed and a communications problem exists. If the Auto Address Procedure failed:
1. Verify ALL indoor unit ON / OFF buttons are in the OFF position (i.e., ON / OFF button NOT illuminated).
2. Check the terminations, polarity, and continuity of each conductor on the communications cable between the outdoor unit and the indoor
units. Verify the indoor unit to outdoor unit communications cable is wired correctly.
3. Verify the shield of the communications cable is grounded at the outdoor unit only. All segment shields must be spliced together at each
indoor unit and NOT grounded.
4. After repairing the communications cable, go to Step 9 of the Initiate the Auto Addressing Procedure and repeat the process until
successful: Press and hold the red SW01C button for about five (5) seconds. Release when “88” appears on the LED. After three (3) to
seven (7) minutes, the display will flash a number for about thirty (30) seconds indicating how many indoor units the system successfully

communicated with.
5. This number must match the known installed number of indoor units if the auto addressing procedure was successful.
6. Upon completion of the auto addressing routine, the display will be blank and the system will be in standby waiting for another command.
7. Record the system address the outdoor unit assigned to each indoor unit by the auto address procedure in the column provided on the
Pre-commissioning Device Configuration Worksheet.
8. After recording the system addresses assigned to each device, open the outdoor unit disconnect. Remove the outdoor unit to indoor unit
communications cable from terminals IDU(A) and IDU(B). Protect conductors by placing electrical tape over the bare ends to prevent an
accidental compressor start from occurring before the LG trained Commissioner arrives.
9. Close the disconnect to reapply power to the outdoor unit and energize the compressor crankcase heater. Once again, verify the outdoor
unit to indoor unit(s) communications cable is not connected to terminals IDU(A) and IDU(B) of the outdoor unit.
10. Replace the control panel cover.
OTHER CONTROLS
Setting Optional Modes
Setting the Functions

To access and set the different modes/functions, first turn No. 5 on DIP Switch SW01 is set to ON. Then select the functions (mode, option,
YDOXHHWFE\XVLQJWKH6:&IRUZDUGŹEXWWRQDQGWKH6:&EDFNZDUGŻEXWWRQV&KRRVHWKHSDUWLFXODUIXQFWLRQE\SXVKLQJWKH
confirm Ɣ button.
Figure 6: Outdoor Unit DIP Switch
SW01 Function Setting.
• To set the optional modes / functions, all indoor units must be OFF. Mode / function settings won’t save,
nor will operate unless all indoor units are OFF. ON
• If system power was reset, some modes / function settings will be automatically saved in the EEPROM.
Other modes / functions will reset when power is cycled off. See next pages for details on specific
modes / functions. OFF
Figure 7: Location of DIP Switches and Setting Buttons on the Figure 8: Location of DIP Switches and Setting Buttons on the
ARUN24~53GSS4 Outdoor Unit PCB. ARUN60GSS4 and ARUB60GSS4 Outdoor Unit PCB.
DIP-Switch SW01 SSD
SSD
SW01C SW01D
( &RQ¿UP 5HVHW
SW04C ( &DQFHO
SW04C
SW02C ( &DQFHO
SW03C ( )RUZDUG ( %DFNZDUG DIP-Switch
SW01
SW03C
SW02C ( %DFNZDUG ( )RUZDUG
SW01C ( &RQ¿UP
6:'5HVHW
Table 25: Setting the Functions.

Mode Selection Selection Selection
Notes
Content Display Mode / Function Name Display Default Options
Cool / Heat Selector Fn1 oFF oFF, oP1 ~ oP2 Saved in EEPROM.
Static Pressure Compensation Fn2 oFF oFF, oP1 ~ oP2 Saved in EEPROM.
Night Low Sound Fn3 oFF oFF, oP1 ~ oP15 Saved in EEPROM.
Function Func
Outdoor Unit Addressing Fn5 0 0~254 Saved in EEPROM.
Snow Removal Assist / Rapid Defrost Fn6 oFF oFF, oP1~oP3 Saved in EEPROM.
Adjusting Target Pressure Fn8 oFF oFF, oP1~oP6 Saved in EEPROM.
Pump Down SE1, Pd Pd -
Vacuum Mode SE3, vAcc vAcc - One Time / One Selection
Forced Oil Return SE5, 01 oFF on, oFF
Forced Defrost SE6, dEF oFF on, oFF
Service SvC SE7 or 8
on, oFF, Shows each cycle value in
Cycle Data View (depends on oFF
oP1~oP26 real time.
model)
SE8 or 9
Refrigerant Sound Reduction Mode (depends on oFF on, oFF, oP1~oP2 Saved in EEPROM.
model)
40
OTHER CONTROLS
&RRO+HDW6HOHFWRU)Q Figure 9: Cool / Heat Selector.

The setting communicates to the outdoor unit that the optional LG Cool / Heat Selector (or appropriate Left Side Right Side
¿HOGSURYLGHGUHOD\VDQGZLULQJWKDWSHUIRUPWKHVDPHWDVNis connected to the system. The Cool / Heat
Selector is field-wired to the “Dry 1” and “Dry 2” terminals located on the master outdoor unit main PCB.
The Cool / Heat Selector has two switches. The two-position upper switch manually locks out heating and
cooling operation, allowing fan only, or heating or cooling operation depending on the position of the low-
Switch
er switch. The two-position bottom switch and manually sets the position of the outdoor unit’s reversing (Up)
valve. If the left side is depressed, the valve is in the cooling position. If the right side is depressed, the
valve is in the heating position. The Cool / Heat Selector also provides a method for locking out compres-
sor operation by placing the “Fan Only” toggle switch in the “On” position.
Switch
• Off (Default): No Cool / Heat Selector installed, or the Cool / Heat Selector is installed, but has not been (Down)
identified by the master outdoor unit.
• On: Cool / Heat Selector installed and operational. When On is selected:
• The left side of the upper switch is depressed. Mechanical refrigeration is locked out and the indoor

unit fans are allowed to operate. The position of the lower switch is irrelevant.
• The right side of the upper switch is depressed, the lower switch has the right side depressed, and the
system is operating in cooling.
• The right side of the upper switch is depressed, the lower switch has the left side depressed, and the system is operating in heating.
Use the Cool / Heat Selector in heat pump systems to set the system mode for all cooling operation, all heating operation, fan only, or dry
operation (when all indoor units have to be in the same mode).
For use in heat pump systems only.
Figure 10: Setting the Cool / Heat Selector Function.

Turn No. 5 on the outdoor unit PCB DIP switch bank SW01 to ON. • The Cool / Heat Selector must be installed
first before setting the cool / heat operation
function.
6HOHFWWKH³)XQF´PRGHE\XVLQJWKH6:&IRUZDUGŹEXWWRQDQGWKH6:&EDFNZDUG
• A trained LG service provider must set this
ŻEXWWRQDQGWKHQSUHVVWKH6:&FRQILUPƔEXWWRQ
function during system installation.
• If cool or heat function is not used, set to OFF.
6HOHFWWKH³)QÍXQFWLRQE\XVLQJWKH6:&IRUZDUGŹEXWWRQDQGWKH6:&EDFNZDUG • Cool / Heat Selector is flagged as the master
ŻEXWWRQDQGWKHQSUHVVWKH6:&FRQILUPƔEXWWRQ on the central control communications bus.
• Cool / Heat Selector is not for use with BMS
Gateway, VMS, or VMS Communications
Select from “oFF”, “op1,” or “op2” options (see table below) by using the SW03C forward Manager.
ŹEXWWRQDQGWKH6:&EDFNZDUGŻEXWWRQDQGWKHQSUHVVWKH6:&FRQILUPƔ
button.
The Cool / Heat Selector function is set. PCB does not need reset.
Table 26: Cool / Heat Selector Function Settings.

Switch Control Function
Switch (Up) Switch (Down) oFF op1 (Mode) op2 (Mode)
Right Side (On) Left Side (On) Not Operating Cooling Cooling
Right Side (On) Right Side (On) Not Operating Heating Heating
Left Side (Off) - Not Operating Fan Mode Off
OTHER CONTROLS
Static Pressure Compensation Figure 11: Setting the Static Pressure Compensation Function.
Function (Fn2) Turn No. 5 on the outdoor unit PCB
Static Pressure Compensation function modifies the maximum DIP switch bank SW01 to ON.
outdoor unit fan speed during normal system operation. Use the
function to raise the maximum outdoor unit fan speed to compensate 6HOHFWWKH³)XQF´PRGHE\XVLQJWKH6:&IRUZDUGŹEXWWRQDQGWKH
for an obstruction (duct) in airflow. 6:&EDFNZDUGŻEXWWRQDQGWKHQSUHVVWKH6:&FRQILUP
ƔEXWWRQ
Refer to the Multi V Engineering Manuals for the default static
pressure rating, and the maximum static pressure rating with this
function engaged. 6HOHFWWKH³)QÍXQFWLRQE\XVLQJWKH6:&IRUZDUGŹEXWWRQDQG
WKH6:&EDFNZDUGŻEXWWRQDQGWKHQSUHVVWKH6:&
FRQILUPƔEXWWRQ
• Ask a trained LG service provider to set this function during system

installation. Select from “oFF”, “op1”, and “op2” options (see table) by using the
• Cooling capacity can be reduced if the outdoor unit RPM is 6:&IRUZDUGŹEXWWRQDQGWKH6:&EDFNZDUGŻEXWWRQ
lowered. DQGWKHQSUHVVWKH6:&FRQILUPƔEXWWRQ
Press the SW01D Reset Button one (1) time to reset PCB.
The selected option value is saved in the EEPROM.
Table 27: Setting Static Pressure Compensation Function.
ARUN060GSS4 ARUN053GSS4,
Model ARUN048GSS4, ARUN038GSS4
oFF (Standard) 800
Maximum RPM op1 850
op2 850
42
OTHER CONTROLS
Night Low Sound Function (Fn3) Figure 12: Setting the Night Low Sound Function.
The Night Low Sound Function reduces the operating speed of the Turn No. 5 on the outdoor unit PCB
outdoor unit fans (according to the input signal) during “off-peak” DIP switch bank SW01 to ON.
hours under normal circumstances when in cooling mode. Operating
at a low RPM reduces the fan sound levels of the outdoor unit at
6HOHFWWKH³)XQF´PRGHE\XVLQJWKH6:&IRUZDUGŹEXWWRQDQGWKH
night (or other off-peak hours), which usually has a low cooling load. 6:&EDFNZDUGŻEXWWRQDQGWKHQSUHVVWKH6:&FRQILUP
On a rolling 24 hour basis, an internal timer begins counting hours ƔEXWWRQ
after the start time (delay set after peak cooling recorded operation),
switching to restricted fan speed duration operation, following what-
6HOHFWWKH³)QÍXQFWLRQE\XVLQJWKH6:&IRUZDUGŹEXWWRQDQG
ever settings have been chosen. WKH6:&EDFNZDUGŻEXWWRQDQGWKHQSUHVVWKH6:&
For use on both heat pump and heat recovery systems. FRQILUPƔEXWWRQ
• Timed algorithm. Restricted fan speed period length and start delay Select from “op1” through “op15” options (see table) by using the
is selectable. 6:&IRUZDUGŹEXWWRQDQGWKH6:&EDFNZDUGŻEXWWRQ
• Delay timer starts each day when, during a one (1) minute period DQGWKHQSUHVVWKH6:&FRQILUPƔEXWWRQ

the highest demand for cooling is recorded by the outdoor unit.
• Request servicer to set the function during installation. Press the SW01D Reset Button one (1) time to reset PCB.
• If the function is not used set the DIP switches to OFF and reset The Night Low Sound function is set; the selected option value is
the power. saved in the EEPROM.
• If the outdoor unit Hz and rpm change, cooling capacity can
decrease.
Table 28: Setting the Time and Related Sound Level.

Start Time Restricted Fan Speed Duration
Settings (Delay after Peak Cooling Recorded) (Hour)* (Hour)
op1 8.0 9.0
op2 6.5 10.5
op3 5.0 12.0
op4 8.0 9.0
op5 6.5 10.5
op6 5.0 12.0
op7 8.0 9.0
op8 6.5 10.5
op9 5.0 12.0
op10 (Default)
op11 Continuous Operation
op12
op13 6.5 10.5
op14 6.5 10.5
op15 6.5 10.5
*The system measures ambient temperature (minimum and maximum) in “Wait Time” to help determine when the system can start operating in Night Low Sound.
OTHER CONTROLS
Outdoor Unit Addressing Function Figure 13: Setting the Outdoor Unit Address Function.
(Fn5) Turn No. 5 on the outdoor unit PCB DIP
switch bank SW01 to ON.
Use this function to set addresses when more than one Multi V
system shares a communications bus linked to a central controller
or BMS gateway. Each system is assigned to a unique outdoor 6HOHFWWKH³)XQF´PRGHE\XVLQJWKH6:&IRUZDUGŹEXWWRQDQG
unit address. The Outdoor Unit Addressing Function will help avoid WKH6:&EDFNZDUGŻEXWWRQDQGWKHQSUHVVWKH6:&
assigning the same address to the different systems; if not properly FRQILUPƔEXWWRQ
addressed, a communication error could occur on one (1) or more of
the systems.
For use on both heat pump and heat recovery systems. WKH6:&EDFNZDUGŻEXWWRQDQGWKHQSUHVVWKH6:&
FRQILUPƔEXWWRQ
• 000 = Default; Central Control Address setting of “000”.
• 001 = Central Control Address setting of “001”.

Select from 0 (Default) through 254 by using the SW03C forward
• Set 1 of 255 Valid Addresses; 000, 001, 002, 003, 004...through ŹEXWWRQDQGWKH6:&EDFNZDUGŻEXWWRQDQGWKHQSUHVV
254. WKH6:&FRQILUPƔEXWWRQ
Outdoor Unit Address is set. PCB does not need reset.

• The central controller or BMS gateway must be installed first before
setting the outdoor unit address.
• A trained LG service provider must set this function during system
installation.
44
OTHER CONTROLS
6QRZ5HPRYDO$VVLVW5DSLG'HIURVW Figure 14: Setting the Snow Removal / Rapid Defrost Function.
Function (Fn6) Turn No. 5 on the outdoor unit PCB
DIP switch bank SW01 to ON.
Snow Removal Assist
Snow Removal Assist function allows the outdoor unit(s) fans to
6HOHFWWKH³)XQF´PRGHE\XVLQJWKH6:&IRUZDUGŹEXWWRQDQGWKH
operate at regular intervals, for two (2) minutes, at specified speeds 6:&EDFNZDUGŻEXWWRQDQGWKHQSUHVVWKH6:&FRQILUP
(as seen in the tables below) to remove snow accumulation from the ƔEXWWRQ
fan discharge.
The function will only operate when the system has not called for
compressor activity (no demand for heating or cooling) for thirty (30) WKH6:&EDFNZDUGŻEXWWRQDQGWKHQSUHVVWKH6:&
minutes, and when the outdoor air temperature is <37ºF. Operates FRQILUPƔEXWWRQ
every thirty (30) minutes for two (2) minutes. Function will stop if
there is an operation error code, or if a compressor starts. Use this
function in areas where snow accumulating on the fan blades and Select from “oFF,” “op1” through “op3” options (see table) by using the
fan guard is common. 6:&IRUZDUGŹEXWWRQDQGWKH6:&EDFNZDUGŻEXWWRQ
DQGWKHQSUHVVWKH6:&FRQILUPƔEXWWRQ

Rapid Defrost
Rapid Defrost function limits the amount of frost and ice are allowed The Snow Removal / Rapid Defrost function is set.
to build on the coil between defrost cycles (defrost cycles occur PCB does not need reset.
more often). System pressure is monitored, and when system pres-
sure is reduced, the defrost cycle is initiated.
• A trained LG service provider must set this function during system

Snow Removal Assist and Rapid Defrost can be used on both heat
installation.
pump and heat recovery systems.
• If the snow removal / rapid defrost mode is not used, set to OFF.
Snow Removal Assist / Rapid Defrost can also be used with Forced
Defrost - SE6.
Table 29: Setting the Snow Removal / Rapid Defrost Function.

Settings Details
oFF (Default) Mode Is Not Set
op1 Snow Removal Assist Mode
op2 Rapid Defrost Mode
op3 Snow Removal Assist Mode and Rapid Defrost Mode
OTHER CONTROLS
Adjusting Target Pressure (Fn8) Figure 15: Adjusting Target Pressure Function.
The Adjusting Target Pressure function modifies the refrigeration Turn No. 5 on the master outdoor unit PCB DIP switch bank SW01 to ON.
cycle’s high and low pressure target values; more specifically, modi-
fies the compressor discharge and suction target operating pressure 6HOHFWWKH³)XQF´PRGHE\XVLQJWKH6:&IRUZDUGŹEXWWRQDQGWKH
values. Can be used to enhance / turn down the cooling or heating 6:&EDFNZDUGŻEXWWRQDQGWKHQSUHVVWKH6:&FRQILUP
capabilities of variable refrigerant flow systems, optimizing refrigera- ƔEXWWRQ
tion cycle operation to maximize operational efficiency.
Separate, unique setting values can be assigned for cooling, and 6HOHFWWKH³)QÍXQFWLRQE\XVLQJWKH6:&IRUZDUGŹEXWWRQDQG
heating operation. WKH6:&EDFNZDUGŻEXWWRQDQGWKHQSUHVVWKH6:&
For use on both heat pump and heat recovery systems. FRQILUPƔEXWWRQ
Select from “oFF, “oP1” through “oP7” options (see table) by using the
6:&IRUZDUGŹEXWWRQDQGWKH6:&EDFNZDUGŻEXWWRQ
Press the SW01D Reset Button one (1) time to reset PCB.
Adjusting Target Pressure is set.
Table 30: Setting Adjusting Target Pressure Function.
Setting Low Pressure Vapor Target psig / kPa (ºF) High Pressure Vapor Target psig / kPa (ºF)
oFF (Default) 117 / 804 (39.5) 434 / 2,990 (122.8)
oP1 105 / 725 (34.0) 453 / 3,121 (126.1)
oP2 111 / 765 (37.0) 443 / 3,056 (124.5)
oP3 126 / 869 (43.5) 410 / 2,827 (118.5)
oP4 136 / 935 (47.5) 386 / 2,663 (114.1)
oP5 145 / 1,000 (51.0) 363 / 2,500 (109.5)
oP6 154 / 1,065 (54.3) 339 / 2,337 (104.8)
oP7 117 / 804 (39.5) 434 / 2,990 (122.8)
46
OTHER CONTROLS
Pump Down for Heat Pump Outdoor Units (SE1, Pd) Table 31: Setting the Pump Down Function.
Pump Down function gathers the refrigerant in the system, and sends it to the outdoor unit. Settings Function
Use Pump Down function when there is a refrigerant leak, or if an indoor unit needs to be oFF (Default) Pump Down is not enabled.
replaced. The maximum refrigerant for outdoor units is size dependent and varies. If the sys- Pump Down is enabled.
tem charge is greater than the volume that can be stored, a supplemental vacuum pump and Pd (on) Display Will Show Low
third-party storage containers will be required. For use on both heat pump and heat recovery Pressure.
systems.
Outdoor Unit Service Valves for Heat

Keep the liquid service valve to the outdoor Pump System Pump Down
unit closed. Open the vapor service valve to
the outdoor unit.
Reset power, then turn No. 5 on the master outdoor unit PCB
DIP switch bank SW01 to ON. Select the “SvC” mode by using
WKH6:&IRUZDUGŹEXWWRQDQG6:&EDFNZDUGŻEXWWRQV

Choose SE1, Pd, and then press the red Close Open
6:&FRQILUPƔEXWWRQ
Operate the system in all indoor unit cooling. *Current low

pressure
Is the low pressure target No Liquid Pipe Vapor Pipe

satisfied.
Outdoor Unit Service Valves for Heat Pump
Note 2) Yes System After Pump Down Is Finished
Pump down complete.

Low pressure <33.2 psi.1 *Current low Close service valves.
pressure
*Low pressure <44.5
psi; light will blink.2
Press the red SW01C

Ɣbutton to confirm.
Close Close
Turn all indoor units and the outdoor unit off.
Turn No. 5 on the master outdoor unit

PCB DIP switch bank SW01 to OFF.
Reset power.
Liquid Pipe Vapor Pipe
1. If low pressure falls below 33.2 psi, immediately close the vapor service valves. (See figures above.)
2. If low pressure falls below 44.5 psi (light will blink), the system will shut off automatically. Immediately close the vapor service valve.
• Use the Pump Down function while ambient conditions are within the manufacturer’s operating temperature ranges:
,QGRRU8QLWV a)2XWGRRU8QLWV a)
• Do not run the indoor units in thermo off mode during Pump Down.
• Maximum operation time of Pump Down is thirty (30) minutes (in case low pressure does not satisfy target levels immediately).
OTHER CONTROLS
Pump Down for Heat Recovery Outdoor Units (SE1, Table 32: Setting the Pump Down Function.
Pd) Settings Function
Pump Down function gathers the refrigerant in the system, and sends it to the outdoor unit. oFF (Default) Pump Down is not enabled.
Use Pump Down function when there is a refrigerant leak, or if an indoor unit needs to be Pump Down is enabled.
replaced. The maximum refrigerant for outdoor units is size dependent and varies. If the sys- Pd (on) Display Will Show Low
tem charge is greater than the volume that can be stored, a supplemental vacuum pump and Pressure.
third-party storage containers will be required. For use on both heat pump and heat recovery
systems.
Keep the high pressure vapor service valve Outdoor Unit Service Valves for Heat
and liquid service valve to the outdoor unit Recovery System Pump Down
closed. Open the low pressure vapor service
valve to the outdoor unit.
Reset power, then turn No. 5 on the master outdoor unit PCB
DIP switch bank SW01 to ON. Select the “SvC” mode by using
WKH6:&IRUZDUGŹEXWWRQDQG6:&EDFNZDUGŻEXWWRQV
Close Close Open

Choose SE1, Pd, and then press the red
6:&FRQILUPƔEXWWRQ
Operate the system in all indoor unit cooling. *Current low

pressure
High Pressure Liquid Pipe Low Pressure
Vapor Pipe Vapor Pipe
Is the low pressure target No

satisfied. Outdoor Unit Service Valves for Heat
Note 2) Yes Recovery System Pump Down
Pump down complete.

Low pressure <33.2 psi.1 *Current low Close service valves.
pressure
*Low pressure <44.5
psi; light will blink.2
Press the red SW01C
Ɣbutton to confirm. Close Close Close
Turn all indoor units and the outdoor unit off.
Turn No. 5 on the master outdoor unit High Pressure Liquid Pipe Low Pressure
PCB DIP switch bank SW01 to OFF. Vapor Pipe Vapor Pipe
Reset power.
1. If low pressure falls below 33.2 psi, immediately close the vapor service valve. (See figures above.)
2. If low pressure falls below 44.5 psi (light will blink), the system will shut off automatically. Immediately close the vapor service valve.
• Use the Pump Down function while ambient conditions are within the manufacturer’s operating temperature ranges:
,QGRRU8QLWV a)2XWGRRU8QLWV a)
• Do not run the indoor units in thermo off mode during Pump Down.
• Maximum operation time of Pump Down is thirty (30) minutes (in case low pressure does not satisfy target levels immediately).
48
OTHER CONTROLS
Vacuum Mode (SE3, vAcc) Figure 17: Location of DIP Switches and Setting Buttons on the
ARUN24~53GSS4 Outdoor Unit PCB.
The vacuum mode can be used as an option for creating vacuum in
the system when the outdoor unit is first installed, if power is avail- DIP-Switch SW01 SSD
able, and if the system has already been auto addressed. Vacuum
mode enables the system to fully open all valves, and can help
speed up the evacuation process.
Vacuum mode can also be used when compressor and / or outdoor
unit parts are replaced, or when an indoor unit is added or replaced.
SW04C ( &DQFHO
1. Turn No. 5 on the outdoor unit PCB DIP Switch SW01 to ON.
2. 6HOHFWWKH³6Y&´PRGH%\XVLQJWKHŹDQGŻEXWWRQVWKHQSXVK SW03C ( )RUZDUG
WKHƔEXWWRQ
3. 6HOHFWWKH³6(ÍXQFWLRQ%\XVLQJWKHŹDQGŻ%XWWRQVWKHQ SW02C ( %DFNZDUG
SXVKWKHƔEXWWRQ SW01C ( &RQ¿UP
4. Press the SW01D Reset Button one (1) time to reset PCB, and 6:'5HVHW

start the vacuum mode “vACC”. In vacuum mode, the outdoor
unit valve is open, the outdoor unit EEV is open, and the indoor Figure 18: Location of DIP Switches and Setting Buttons on the
unit(s) EEV(s) is/are open. The heat recovery unit(s) valve(s) and ARUN60GSS4 and ARUB60GSS4 Outdoor Unit PCB.
EEVs are open (if system is a heat recovery system).
5. To cancel the vacuum mode, turn No. 5 on the outdoor unit PCB
DIP Switch SW01 to OFF, and push the SW01D reset button on
the outdoor unit PCB. SSD
Figure 16: Vacuum Mode DIP Switch. SW01C SW01D

( &RQ¿UP 5HVHW
ON SW04C
SW02C ( &DQFHO
( %DFNZDUG DIP-Switch
OFF SW01
1 2 3 4 5 6 7 SW03C
( )RUZDUG
Setting Vacuum Mode

Canceling Vacuum Mode
Turn Outdoor Unit PCB No. 5 DIP Switch to ON.
Turn on Outdoor Unit.
<AND>
6HOHFWWKH³6Y&´0RGH%\8VLQJWKHŹDQGŻ%XWWRQVWKHQ3XVK
WKHƔ%XWWRQ Push the Reset Button on the Outdoor Unit PCB. On a Multi-
Frame System, Push the Reset Button on ALL Outdoor Units.
6HOHFWWKH³6H´)XQFWLRQ%\8VLQJWKHŹDQGŻ%XWWRQVWKHQ
3XVKWKHƔ%XWWRQ
• Outdoor unit operation stops during Vacuum Mode, so the com-
pressor cannot operate.
• Limit vacuum mode to less than 48 hours of continuous operation.
Start the Vacuum Mode “vACC.” If vacuum mode is not stopped, the system will continue to operate
• Outdoor Unit Valve is Fully Open. with all EEVs and valves open on the non-vacuum mode termi-
• Outdoor Unit EEV is Fully Open. nated slave outdoor units. The refrigerant will flood back to the
compressors on those non-vacuum mode terminated slave outdoor
• Indoor Unit(s) EEV(s) is/are Fully Open. units, which will result in poor operation, equipment malfunction
• Heat Recovery Unit(s) Valves and EEVs are Fully Open. and / or compressor damage.
OTHER CONTROLS
Forced Oil Return (SE5, 01) Figure 19: Setting the Forced Oil Return Function.
The Forced Oil Return function overrides LG’s Smart Oil Manage- Turn No. 5 on the outdoor unit PCB
ment algorithm, replacing it with a timed oil return that initiates every DIP switch bank SW01 to ON.
fifteen (15) minutes when the sensor indicates the oil level is low.
Use the function in applications where oil return has been problem- 6HOHFWWKH³6YF´PRGHE\XVLQJWKH6:&IRUZDUGŹEXWWRQDQGWKH
atic, a compressor failed due to low oil and the cause is unknown. 6:&EDFNZDUGŻEXWWRQDQGWKHQSUHVVWKH6:&FRQILUP
ƔEXWWRQ
For use on both heat pump and heat recovery systems.
Table 33: Setting Forced Oil Return Function. 6HOHFWWKH³6(ÍXQFWLRQE\XVLQJWKH6:&IRUZDUGŹEXWWRQDQG
Settings Function FRQILUPƔEXWWRQ
oFF (Default) Forced Oil Return is Disabled.
Forced Oil Return is Enabled. Oil Return Occurs

01 6HOHFWIURP³R))´RU³É\XVLQJWKH6:&IRUZDUGŹEXWWRQDQG
Every Fifteen (15) Minutes When Low.
FRQILUPƔEXWWRQ
The Forced Oil Return function begins. PCB does not need reset.
Forced Defrost (SE6, dEF) Figure 20: Setting the Forced Defrost Function.
The Forced Defrost function overrides LG’s defrost algorithm when Turn No. 5 on the outdoor unit PCB
the outside ambient air temperature is <14ºF, occurring every three DIP switch bank SW01 to ON.
(3) hours irrelevant of need. Use the function when defrost at low
ambient temperatures does not completely clear the coil, and the 6HOHFWWKH³6YF´PRGHE\XVLQJWKH6:&IRUZDUGŹEXWWRQDQGWKH
frost that remains impacts comfort levels. It can also be used on 6:&EDFNZDUGŻEXWWRQDQGWKHQSUHVVWKH6:&FRQILUP
installations where the outdoor unit heating capacity needs to be op- ƔEXWWRQ
timized at all times during low ambient operation to maintain comfort.
6HOHFWWKH³6(ÍXQFWLRQE\XVLQJWKH6:&IRUZDUGŹEXWWRQDQG
For use on both heat pump and heat recovery systems. WKH6:&EDFNZDUGŻEXWWRQDQGWKHQSUHVVWKH6:&
FRQILUPƔEXWWRQ
Forced Defrost can also be used with Fn6 - Snow Removal Assist /
Rapid Defrost (oP2 or oP3). 6HOHFWIURP³R))´RU³G()É\XVLQJWKH6:&IRUZDUGŹEXWWRQ
DQGWKH6:&EDFNZDUGŻEXWWRQDQGWKHQSUHVVWKH6:&
Table 34: Setting Forced Defrost Function. FRQILUPƔEXWWRQ
Settings Function
oFF (Default) Forced Defrost is Disabled. The Forced Defrost function begins. PCB does not need reset.
Forced Defrost is Enabled. Oil Return Occurs Every
dEF
Three (3) Hours Irrelevant of Need.
50
OTHER CONTROLS
Cycle Data View (SE7 or SE8 [De- Figure 21: Setting the Cycle Data View Function.
pends on Model]) Turn No. 5 on the outdoor unit PCB
Cycle Data View displays the cycle data of the operating outdoor DIP switch bank SW01 to ON.
unit. Cycle Data View can display up to 26 different cycle datapoints
(depending on the outdoor unit) on the SSD. 6HOHFWWKH³6YF´PRGHE\XVLQJWKH6:&IRUZDUGŹEXWWRQDQGWKH
6:&EDFNZDUGŻEXWWRQDQGWKHQSUHVVWKH6:&FRQILUP
ƔEXWWRQ
Select the “SE7” or “SE8” (depends on model) function by using the

6:&IRUZDUGŹEXWWRQDQGWKH6:&EDFNZDUGŻEXWWRQ
Select from “oP1” through “oP26” by using the SW03C forward

ŹEXWWRQDQGWKH6:&EDFNZDUGŻEXWWRQDQGWKHQSUHVV
WKH6:&FRQILUPƔEXWWRQ

The Cycle Data View function begins. See table below for “oP1”
through ‘oP26” option information.
Table 35: Cycle Data View Datapoint Options.

Option Description Display Example seg_1 seg_2 seg_3 seg_4
op1 Current High Pressure P1 4,321 kPA (626.7 psi) 4 3 2 1
op2 Current Low Pressure P2 1,234.2 kPA (179 psi) 1 2 3 4
op3 Inverter Compressor h1 120 Hz 1 2 0
op4 Fan 1 h3 110 rpm 1 1 0
op5 Fan 2 h4 110 rpm 1 1 0
op6 Degree of Superheating T1 53°C (127.4°F) 5 3 0
op7 Degree of Subcooling T2 -4.5°C (23.9°F) - 4 5
op8 Outdoor Unit Temperature T3 10°C (50°F) 1 0 0
op9 Suction Temperature T4 43.4°C (110.1°F) 4 3 4
op10 Compressor Discharge Temperature T5 150°C (302°F) 1 5 0 0
op12 Liquid Pipe Temperature T7 10°C (50°F) 1 0 0
op14 Sc_out T9 10°C (50°F) 1 0 0
op15 Hex T10 10°C (50°F) 1 0 0
op18 Inlet Pipe Temperature of Indoor Unit T13 -10°C (14°F - 1 0 0
op19 Main EEV PLS1 1,950 1 9 5 0
op21 SC EEV PLS3 16 1 6
op25 Operation Capacity of Indoor Units IDU1 24,000 2 4
op26 Total Number of Indoor Units IDU2 10 1 0
OTHER CONTROLS
Refrigerant Sound Reduction Mode Figure 22: Setting the Refrigerant Sound Reduction Function.
(SE8 or SE9 [Depends on Model]) Turn No. 5 on the outdoor unit PCB
This function reduces refrigerant flow sound in the liquid piping DIP switch bank SW01 to ON.
caused by mixed-state refrigerant by adjusting air flow across the
outdoor unit coil. It reduces the refrigerant flow sound at all indoor 6HOHFWWKH³6YF´PRGHE\XVLQJWKH6:&IRUZDUGŹEXWWRQDQGWKH
units when system is operating in heating or cooling. The function 6:&EDFNZDUGŻEXWWRQDQGWKHQSUHVVWKH6:&FRQILUP
will impact all indoor units; selective indoor unit application is not ƔEXWWRQ
possible.
Select the “SE8” or “SE9” (depends on model) function by using the
In cooling, when the compressor speed remains constant, reduc- 6:&IRUZDUGŹEXWWRQDQGWKH6:&EDFNZDUGŻEXWWRQ
ing the airflow over the outdoor unit coil raises head pressure and DQGWKHQSUHVVWKH6:&FRQILUPƔEXWWRQ
sub-cooling. Increased subcooling reduces the possibility that gas
bubbles will form in the liquid line before reaching the indoor unit Select from “oFF”, “on”, “oP1”, or “oP2” (depends on model) by using
EEVs. WKH6:&IRUZDUGŹEXWWRQDQGWKH6:&EDFNZDUGŻ
EXWWRQDQGWKHQSUHVVWKH6:&FRQILUPƔEXWWRQ
In heating, when the compressor speed remains constant, the
temperature of the superheated gas leaving the compressor and en- Press the SW01D Reset Button one (1) time to reset PCB.
tering the indoor coil is reduced. This results in slightly less heating The Refrigerant Sound Reduction function begins.
performance, but sub-cooling rises in the liquid leaving the indoor
(condenser) coil. More sub-cooling keeps gas bubbles from forming
before the liquid passes through the condenser coil EEV valve.
• Because of the restricted refrigerant flow, it will take longer to preheat the coil on startup.
• An incorrect charge can result in refrigerant flow related sound. Verify the system’s refrigerant charge is correct before using this function.
• Ask a trained service provider to set this function.
• Power consumption or efficiency will change if the Refrigerant Sound Reduction Mode is set.
Table 36: Setting the Refrigerant Sound Reduction Function for Multi V Table 37: Setting the Refrigerant Sound Reduction Function for Multi V
S 24-53K Heat Pump Systems. S 60 Heat Pump and Heat Recovery Systems.
Settings Function Setting Function
oFF Refrigerant Noise Reduction Mode is Disabled oFF Fast Cooling and Fast Heating
on Refrigerant Noise Reduction Mode is Enabled oP1 Strong Refrigerant Noise Reduction Mode
oP2 Mild Refrigerant noise reduction Mode
52
HEAT RECOVERY UNIT PARTS
Table 38: Heat Recovery Unit Parts Table.

Name Symbol Function
Low Pressure Vapor Pipe LPGV Pipe for Low Pressure Vapor
High Pressure Vapor Pipe HPGV Pipe for High Pressure Vapor
Liquid Pipe 1 LP1 Liquid Pipe to the Outdoor Unit(s)
Liquid Bypass Valve LBV Prevents Liquid Charge
Solenoid Assembly 1, 2 SOL1, 2 Controls Path for Heating or Cooling
Liquid Pipe 2 LP2 Liquid Pipe to the Indoor Unit(s)
Vapor Pipe GSP Vapor Pipe to the Indoor Units
Controls the Pressure Between High and Low Pressure
Balancing Valve BLV
Pipes During Operation Changeover
Subcooling EEV SCEEV Controls Subcooling
Heat Recovery Unit Functions

Figure 23: Heat Recovery Unit Parts Diagram. Liquid Pipe 1
Low Pressure Vapor Pipe

High Pressure Vapor Pipe
Subcooling EEV
Balancing Valve
Vapor Pipe
Liquid Pipe 2
Liquid Bypass Valve
Solenoid Assembly 1
Solenoid Assembly 2
HEAT RECOVERY UNIT
DIMENSIONAL DIAGRAMS
PRHR022A Heat Recovery Unit

54
HEAT RECOVERY UNIT
HEAT RECOVERY UNIT

56
HEAT RECOVERY UNIT
WIRING DIAGRAM
PRHR022A, 032A, 042A
HEAT RECOVERY UNIT
REFRIGERANT CIRCUIT DIAGRAM
PRHR022A, 032A, 042A
Low-Pressure Vapor Pipe
Liquid Pipe
High-Pressure Vapor Pipe
Solenoid
Liquid pipe
Vapor pipe
Liquid pipe
Vapor pipe
Liquid pipe
Vapor pipe
Liquid pipe
Vapor pipe
EEV
Sensor
A : Switches operation between cooling and heating.

B : Decreases noise following subcooling operation between inlet of one indoor unit and outlet of another indoor unit during simultaneous
operation.
C : Prevents liquid from entering high-pressure vapor valve and heat recovery unit during cooling mode.
D : Controls pressure between the high and low pressure vapor pipes during simultaneous operation.
58
HEAT RECOVERY UNIT FUNCTIONS
Basic Control
Normal Operation
Table 39: Normal Operation Functions.
Component Power On Cooling Operation Heating Operation Stop Operation
High Pressure Vapor Valve Close Close Open Keep
Open after thirty (30)
Low Pressure (Vapor Valve Open Close Keep
seconds
Liquid Valve Close Open Close Close
Start Control (Heating Mode Only)

When the system operates in heating mode, all of the high pressure vapor valves in the heat recovery unit are open.
Valve Control

See Mode Change Time Calculations in the "Mode Change Time Calculation" table. How the valves are controlled by the Mode Change Time
can be seen in the "Valve Control by Mode Change Time" table.
Table 40: Mode Change Time Calculation.

Previous Mode Change Mode Mode Change Time
Stop or Ventilation Cooling or Heating 120 seconds
Cooling Heating 180 seconds
Heating Cooling 120 seconds
During Heating: 60 seconds
Cooling or Heating Stop or Ventilation
During Cooling: 0 seconds
The time of Mode Change Time will differ based on the software version of the heat recovery unit PCB.
Table 41: Valve Control by Mode Change Time.

Operation Mode Mode Change Time High Pressure Vapor Valve Low Pressure Vapor Valve Balancing Valve
7LPH Keep Keep Close
Cooling 0 < Time < 120 Close Close Open
Time = 0 Close Open Close
7LPH Keep Keep Close
Heating 0 < Time < 180 Close Close Close
Time = 0 Open Close Close
0 < Time < 5 Cooling Mode: Close Keep Close
Stop or Ventilation Heating Mode: Low Pressure
Time = 0 Keep Close
9DSRU9DOYHĺ&ORVH
HEAT RECOVERY UNIT FUNCTIONS
Special Control
2LO5HWXUQ'HIURVW&RQWURO
Table 42: Oil Return / Defrost Control.
Component Start During Operation Stop
Inverter Compressor Stop 60 Hz 40 Hz
High Pressure Vapor Valve Keep Close Open or Close
Low Pressure Vapor Valve Keep Open Open or Close
Balancing Valve Open for 30 seconds Close Close
Liquid Bypass Control

Are the Indoor Units Operating?
Are All the Indoor Units No

Operating in Cooling Mode?
Yes
Solenoid Valve Open for Liquid

%\SDVV+LJK3UHVVXUH9DSRUĺ
Low Pressure Vapor Valve).
Subcooling EEV Control

Subcooling EEV operates with fuzzy logic to keep the degree of subcooling (Target: About 77°F) at the outlet of the subcooler during simulta-
neous cooling / heating operation.
Temperature of Subcooler = T Subcooler Outlet – T Subcooler Inlet
60
HEAT RECOVERY UNIT SETTINGS
Addressing with Heat Recovery Units Figure 24: Heat Recovery Unit Main PCB.
Air Valve Housing
(For Heat Recovery Systems Only) No. 1 Valve Housing
General
Each heat recovery unit will have a unique address assign so the
outdoor unit will be able distinguish it from other heat recovery units.
Upon completion of the heat recovery unit address, the heat recov-
ery unit operating parameters will be set by adjusting the positions
DIP switches on SW02M and SW01M.
Procedure LED
Before beginning the physical process of assigning heat recovery

addresses, map out the address assignments using a copy of the SW05M
LATS tree mode diagram.

SW01M
Guidelines
1. Addresses must be sequential and cannot be skipped.
SW02M SW03M SW04M (SW01M / SW03M / SW04M
Switches for Manual Valve Addressing)
2. Assign the lowest address to the heat recovery unit that has the (DIP Switch for Set Up of Heat
PCB Settings
Recovery Unit Functions)
largest capacity indoor unit connected to port number 1. If the
capacity of all indoor units connected to port number 1 of each heat recovery unit is the same, assign address “0” to the heat recovery
unit farthest away from the outdoor unit. Assign the next address to the next farthest away and so on until all heat recovery units have an
address. The heat recovery unit with the highest address must be the one closest to the outdoor unit. Up to 16 heat recovery units can be
on a single system.
Possible settings in order of lowest to highest are: 0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F.
Addressing must be performed following the detailed steps above because port number 1 on the heat recovery unit addressed “0” will remain open
during the auto pipe detect procedure. If the indoor unit capacity connected to the port is relatively small compared with other units on the system,
the outdoor unit high head pressure safety will trip and shut down the unit during the procedure.
3. Record the address assigned to each heat recovery unit.
Figure 25: Close Up of DIP Switches and Rotary Dial on the Heat Recovery Unit Main PCB.
SW05M
SW01M
SW02M SW03M SW04M (SW01M / SW03M / SW04M

(DIP Switch for Set Up of Heat Switches for Manual Valve Addressing)
Recovery Unit Functions)
1. Main Function of SW02M.

ON S/W Selection
No. 1 Method for addressing the heat recovery control valves (Auto / Manual)
ON No. 2 Model of heat recovery unit
No. 3 Model of heat recovery unit
OFF No. 4 Valve group setting
1 2 3 4 5 6 7 8 No. 5 Valve group setting
1 2 3 4 5 6 7 8 No. 6 Valve group setting
No. 7 Used only in factory production (preset to “OFF”)
Zone setting (“ON”)
No. 8 Used only in factory production (preset to “OFF”)
Selecting the Heat Recovery Unit Valve Addressing Method (Pipe Detection) (Auto / Manual).
Auto (Switch No. 1 on SW02M OFF) Manual (Switch No. 1 on SW02M ON)
ON ON
OFF OFF
1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8
1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8
Zone Control Setting.
DIP Switch Settings
SW02M SW01M
ON ON
Normal Control
OFF OFF
1 2 3 4 5 6 7 8 1 2 3 4
1 2 3 4 5 6 7 8 1 2 3 4
SW02M SW01M Turn the DIP Switch of the zoned

ON ON branch to ON.
Zone Control
OFF OFF Example: Branches one (1) and
1 2 3 4 5 6 7 8 1 2 3 4 two (2) are set to zone control.
1 2 3 4 5 6 7 8 1 2 3 4
62
Select the Heat Recovery Unit Model.

1. Identify how many ports are connected (see table below).
2. Group ports if necessary. If any connected indoor units are “large” capacity models (indoor units with >54,000 Btu/h capacity) two heat
recovery ports must be “grouped” to serve a large capacity indoor using an inverted ‘Y” branch.
3. Set switches on SW02M as outlined in the table below and on the next page.
Table 43: Selecting the Heat Recovery Unit Model.
2 3 3 4
1 1
2 1 2
PRHR022A (Two [2] ports) PRHR032A (Three [3] ports) PRHR042A (Four [4] ports)
ON ON ON
Factory Setting
OFF OFF OFF
1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8
PCB Settings
1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8
One port ON ON ON
connected
OFF OFF OFF
1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8
1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8
Two ports ON ON ON
connected OFF OFF OFF
1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8
1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8
ON ON
Three ports
connected OFF OFF
1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8
1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8
ON
Four ports
connected OFF
1 2 3 4 5 6 7 8
1 2 3 4 5 6 7 8
DIP Switch SW02M bank is factory set to all OFF for all heat recovery units.
• To use a PRHR022A for one port, cap off the second pipe, and set the DIP switches on the heat recovery unit for "one port connected" as
shown in the table above.
• To use a PRHR032A for two ports, cap off the third port, and set the DIP switches on the heat recovery unit for "two ports connected" as
shown in the table above.
• To use a PRHR042A for three ports, cap off the fourth port, and set the DIP switches on the heat recovery unit for "three ports connected"
as shown in the table above.
• To use a PRHR042A for two ports, cap off the third and fourth ports, and set the DIP switches on the heat recovery unit for "two ports
connected" as shown in the table above.
• Any unused port must be sealed with a brazed copper cap, not with a plastic cap.
Select the Valve Group.

Table 44: SW02M Valve Group Settings.
DIP Switch Setting Example
ON 4 Indoor unit
3 Indoor unit
No Valve Group OFF
2
1 Indoor unit
Control 1 2 3 4 5 6 7 8 Indoor unit
1 2 3 4 5 6 7 8
ON 4 Indoor unit
No. 1, 2 Valve 2
3 Indoor unit
Control OFF 1 Large capacity indoor unit
1 2 3 4 5 6 7 8
1 2 3 4 5 6 7 8
ON 4 Indoor unit
No. 2, 3 Valve 3 Large capacity indoor unit
2
Control OFF
1 2 3 4 5 6 7 8 1 Indoor unit
1 2 3 4 5 6 7 8
ON
No. 3, 4 Valve 4
3
Large capacity indoor unit
Control OFF 2 Indoor unit
1 2 3 4 5 6 7 8 1 Indoor unit
1 2 3 4 5 6 7 8
No. 1, 2 Valve
ON
Control 4
3 Large capacity indoor unit
OFF 2 Large capacity indoor unit
No. 3, 4 Valve 1 2 3 4 5 6 7 8 1
1 2 3 4 5 6 7 8
Control
64
If large capacity indoor units (larger than 54,000 Btu/h) are installed, the Y-branch pipe shown in the table below must be used to twin
Unit: Inch the ports.
Kit Model Vapor Pipe Liquid Pipe
No. Vapor Pipe Dimensions Model No. Liquid Pipe Dimensions Model No.
I.D. 7/8 I.D. 3/4 I.D. 1/2
I.D. 1 I.D. 5/8 I.D. 3/8 I.D. 3/8 I.D. 1/4
I.D. 3/4 I.D. 1/2
2
1
I.D. 3/4 I.D. 1/2
ARBLN03321 I.D. 5/8 I.D. 1/2 3-5/16
AJR54072906 I.D. 1/2 I.D. 3/8 I.D. 1/4 2-15/16 AJR54072902
15-3/8
3 12-5/8
16-1/4
13-1/16
I.D. 1-1/8 I.D. 7/8
I.D. 7/8
O.D. 3/4 O.D. 1 O.D. 3/4
I.D. 1
3 1 2
2-3/4 3-3/16 4-3/8
2. SW05M Function (Rotary Switch for Addressing Heat Recovery Units).

• Rotary switch SW05M must be set to "0"’ when install- Figure 26: Adjusting the Heat Recovery Unit Addresses.
ing only one heat recovery unit.
• When installing multiple heat recovery units, address A B A B A B
PCB Settings
each unit with sequentially increasing numbers start-
ing from "0". 3 4 3 4 3 4
1 2 1 2 1 2
6:06:06:0
(DIP and Tact Switches) for Manual Valve Addressing
Non-zoning (Normal Setting).
• Set the address of the heat recovery unit valve to the central control address of the connected indoor unit.
• SW01M: Select the valve to address.
• SW03M: Increases the valve address by ten (10).
• SW04M: Increases the valve address by one (1).
• Indoor units must be addressed first with a central control address.

• Each indoor unit must have a unique, preset central control address (using its wired controller) before manual valve addressing can occur.
Table 45: Settings for Manual Valve Addressing, Non-Zoning.
PCB Component S/W No. Set Up
SW01M No. 1 Manual Addressing Valve No. 1
ON
No. 2 Manual Addressing Valve No. 2
OFF
1 2 3 4 No. 3 Manual Addressing Valve No. 3
SW03M Increases the Valve Address by Ten (10)
SW04M Increases the Valve Address by One (1)
6:06:06:0',3DQG7DFW6ZLWFKHVIRU0DQXDO9DOYH

Addressing, continued.
Zoning
• Set the address of the heat recovery unit valve to the central control address of the connected indoor unit.
• SW01M: Select the valve to address.
• SW03M: Increases the valve address by ten (10).
• SW04M: Increases the valve address by one (1).
• SW05M: Rotary switch
Each indoor unit must have a unique, preset central control address (using its wired controller) before manual valve addressing can occur.
Table 46: Settings for Manual Valve Addressing, Zoning.

PCB Component S/W No. Set Up
SW01M No. 1 Manual Addressing Valve No. 1
ON No. 2 Manual Addressing Valve No. 2
OFF
1 2 3 4
No. 3 Manual Addressing Valve No. 3
SW03M Increases the Valve Address by Ten (10)
SW04M Increases the Valve Address by One (1)
SW05M Manual Addressing of Zoned Indoor Units
66
INDOOR UNIT ADDRESSING
Indoor Unit Auto Addressing Procedure
Disconnects must only be operated by a properly licensed electrician at this time. Never look at a disconnect switch when closing. Turn away
from the switch when closing. Incorrect wiring could cause the disconnect to explode, physical injury, and / or death.
• Supply power to the indoor units. If power is not supplied, an operation error will occur.
• Error No. CH200 will appear when the auto addressing procedure has failed. See the Troubleshooting section for information on how to
resolve Error No. CH200.
• During the pre-commissioning process for systems with Gen 4 indoor units, do not change any DIP switch settings except for No. 3
on SW01B, which must be ON to enable Gen. 4 features. All other combinations of switches (one [1] through seven [7]) must be left in the
OFF position on the outdoor unit DIP switch bank SW01B.
• If the Auto Address Procedure has never been successfully completed for the system, the compressor(s) will not start when power is
applied to the unit.
• Auto addressing is only possible on the PCB of the outdoor unit.
• If an indoor unit PCB has been replaced, the auto addressing procedure must be performed again.
1. Verify all that all indoor units connected to the system have power to the PCB board AND all zone controller system start buttons are OFF.
2. Remove the maintenance access panel and unit control box cover from the outdoor unit. Place panels and screws in a secure area.
PCB Settings
3. Verify that the communications cable between the indoor units and the outdoor unit is terminated at the outdoor unit terminals IDU(A) and
IDU (B).
4. Verify the shield on the communications cable is grounded at the outdoor unit. The shields must be tied together and taped back.
5. Check if all DIP switches are set to OFF.
6. Cycle power on the outdoor units, indoor units, etc., and wait three (3) minutes while the outdoor unit sequences through the self-diagnos-
tics check, and to improve indoor unit communication when initial power is supplied. Leave disconnect in the “ON” position.
7. Check the outdoor unit(s) current configuration code(s). Observe the unit setup codes using the SSD display found on the outdoor unit
PCB. Each code will display for two (2) seconds.
After the self-diagnostics check is complete, the SSD must be clear and nothing displayed. Diagnostic process must take from three (3) to seven (7)
minutes.
8. Know how many indoor units are connected to the system.
9. Press and hold the red SW01C button for about five (5) seconds. Release when “88” appears on the SSD. After three (3) to seven (7)
minutes, the display will flash a number for about ten (10) to thirty (30) seconds indicating how many indoor units the system successfully
communicated with.
10. This number must match the known installed number of indoor units if the auto addressing procedure was successful. If using LGMV,
read the address of each indoor unit. The address of each indoor unit is also indicated on wired remote control displays.
12. Upon successful completion of the auto address procedure, record the system address assigned to each indoor unit by the auto address
procedure.
INDOOR UNIT ADDRESSING
Figure 27: Auto Address Button Location on ARUN24~53GSS4 Outdoor Figure 28: Auto Address Button Location on ARUN60GSS4 and
Unit PCB. ARUB60GSS4 Outdoor Unit PCB.
DIP-Switch SW01 SSD
SSD
SW01C SW01D
( &RQ¿UP 5HVHW
SW04C ( &DQFHO
SW04C
SW02C ( &DQFHO
SW03C ( )RUZDUG ( %DFNZDUG DIP-Switch
SW01
SW03C
SW02C ( %DFNZDUG ( )RUZDUG
SW01C ( &RQ¿UP
6:'5HVHW
Figure 29: Indoor Unit Auto Addressing Procedure Flowchart.

Turn Power On.
Wait Three (3) Minutes.
Press and Hold Red SW01C

Button for Five (5) Seconds.
Automatic Addressing Begins.

LED Shows = 88
Release Red SW01C Button.
Automatic Addressing Settings Ends.

Numbers of indoor units with complete
Wait Two (2) to Seven (7) Minutes. addressing are displayed for thirty (30)
seconds on the LED after setting is complete.
LED Shows = 88 NO Check Communications

Cable Connections.
YES
Indoor address number is shown on wired remote controller or on the indoor unit
display. This is not an error message, and will disappear when the ON / OFF button
is pressed on the remote controller. Example: Display of 01, 02... 15 indicates that
fifteen (15) indoor units are connected and the automatic addressing has been
Auto Addressing Successful. successfully completed.
68
INDOOR UNIT AUTO ADDRESSING
Troubleshooting a Failed Indoor Unit Auto Addressing Procedure
If the quantity of indoor units the auto addressing procedure found is incorrect, or the “88” never disappears from the display for the seven (7) min-
utes, the auto address routine has failed and a communications problem exists. If the Auto Address Procedure failed:
1. Verify ALL indoor unit ON / OFF buttons are in the OFF position (i.e., ON / OFF button NOT illuminated).
2. Check the terminations, polarity, and continuity of each conductor on the communications cable between the outdoor unit and the indoor
units. Verify the indoor unit to outdoor unit communications cable is wired correctly.
3. Verify the shield of the communications cable is grounded at the outdoor unit only. All segment shields must be spliced together at each
indoor unit and NOT grounded.
4. After repairing the communications cable, go to Step 9 of the Initiate the Auto Addressing Procedure and repeat the process until
successful: Press and hold the red SW01C button for about five (5) seconds. Release when “88” appears on the SSD. After three (3) to
seven (7) minutes, the display will flash a number for about thirty (30) seconds indicating how many indoor units the system successfully
communicated with.
5. This number must match the known installed number of indoor units if the auto addressing procedure was successful.
PCB Settings
7. Record the system address the outdoor unit assigned to each indoor unit by the auto address procedure.
PIPE DETECTION ADDRESSING
Auto Addressing for Pipe Detection

Auto addressing for pipe detection function sets the connection relationship automatically between the indoor units and the heat recovery
units.
1. Turn No.1 of SW02M on the heat recovery unit PCB to OFF.
2. Confirm that the setting of Nos. 2, 3 of SW02M corresponds with the number ports used.
3. Reset the power of heat recovery unit PCB.

Turn master outdoor unit PCB No. 5 DIP switch to ON.
4. 6HOHFWWKH³,GX´PRGHXVLQJŹDQGŻWKHQSXVKWKHƔEXWWRQ
5. 6HOHFWWKH³,G´³$WK´RU³$WFÍXQFWLRQXVLQJŹDQGŻWKHQSXVKWKHƔEXWWRQ,IRXWGRRUWHPSHUDWXUHLV!)XVH³$WK´,IWKDWGRHV
not work, use “Atc.” If outdoor temperature is <59°F, use “Atc”. If that does not work, use “Ath.”
Atc = “At-cold outside”, and Ath = “At-hot outside”. Select accordingly.
6. 6HOHFWWKH³,GX´PRGHXVLQJŹDQGŻWKHQSXVKWKHƔEXWWRQ
7. 6HOHFWWKH³,G6W$ÍXQFWLRQXVLQJŹDQGŻWKHQSXVKWKHƔEXWWRQ
8. The number “88” is displayed on the SSD of the outdoor unit main PCB. If the display shows ------, then wait longer.
9. The automatic pipe detection procedure starts.
10. The procedure will run from five (5) to sixty (60) minutes, depending on the number of connected indoor units, and the ambient outdoor
temperature.
11. The number of indoor units detected is displayed for thirty (30) seconds to one (1) minute on the outdoor unit PCB after the outdoor unit
stops.
• The number of indoor units connected to each heat recovery unit will be displayed.
• If there is an auto pipe detection error, “200” will be displayed.
• Run the auto addressing and auto pipe detection procedures again whenever an indoor unit PCB and / or and heat recovery unit PCB are
replaced. Apply power to the indoor units and heat recovery units after the repair is complete, otherwise operation errors will occur.
• Error No. 200 occurs if the number of actual connected indoor units and the number of detected indoor units are different.
• If the auto pipe detection procedure fails, perform the manual pipe detection procedure. (If the auto pipe detection procedure is successful,
the manual pipe detection procedure is not required.)
• The auto pipe detection procedure can be run again after a failed auto pipe detection procedure attempt; just reset the outdoor unit first.
• Do not turn off the main unit PCB for at least five (5) minutes after the auto pipe detection procedure is complete; allow time for the
outdoor unit to automatically save auto pipe detection results.
70
Figure 30: Auto Addressing for Pipe Detection Procedure Flowchart.
Confirm indoor unit address settings.
Turn No. 1 of SW02M of heat recovery unit

PCB to OFF.
Confirm that the settings of Nos. 2, 3 of

SW02M correspond to the number of ports
used.
Outdoor unit operates for five (5) to sixty
Optional (based on site requirements): (60) minutes.
If a large capacity indoor unit is installed:
Check the settings of Nos. 4, 5, 6 on
SW02M.
If zoning, confirm Nos. 7, 8 of SM02M are set
to ON, then confirm that the individual port
DIP switch is in the ON position for SW01M. Is the pipe setting condition NO
PCB Settings
satisfied during indoor unit operation?
Display error on outdoor unit PCB.

Reset the power of heat recovery unit PCB. Display error on heat recovery unit PCB.
YES
Turn master outdoor unit PCB No. 5 DIP Outdoor unit PCB: HR ĺ HR unit
switch to ON. number ĺ Valve number
The number of indoor units detected is
Heat recovery unit: "200"
displayed for thirty (30) seconds to one (1)
Select the “Idu” mode using ŹDQGŻWKHQ minute on the outdoor unit PCB after the
push the Ɣ button.
outdoor unit stops.
Check heat recovery and indoor
units.
Select the “Id 5” “Ath” or “Atc” function using Ź
DQGŻWKHQpush the Ɣ button.
If outdoor temperature is >59°F, use “Ath”.
If that does not work, use “Atc.” Are the numbers
If outdoor temperature is <59°F, use “Atc”. of indoor units connected to the NO
If that does not work, use “Ath.” outdoor unit and displayed on the
LED the same?
Pipe detection error occurs after

YES thirty (30) seconds.
Select the “Idu” mode using ŹDQGŻWKHQ
push the Ɣ button.
Check the pipe installation of the

Select the “Id 6 StA” function using ŹDQG Auto pipe detection is complete. outdoor, indoor, and heat recovery
Żthen push the Ɣ button. units.
"88" displays on the LED of the outdoor unit Retry the auto pipe detection
main PCB. procedure after troubleshooting.
Auto pipe detection is incomplete.
Manual Pipe Detection Addressing Figure 32: Location of DIP Switch SW02M on the Heat Recovery Unit
Main PCB.
1. Enter the central control address into each indoor unit using its
SW05M
wired remote control. If a controller is not available, a controller
needs to be added.
2. Turn No. 1 of DIP switch bank SW02M of the heat recovery unit
SW01M
PCB ON.
3. Reset the power of the heat recovery unit PCB.
4. Through the heat recovery unit PCB, manually set address of
each heat recovery unit valve to the central control address of the SW02M SW03M SW04M (SW01M / SW03M / SW04M
(DIP Switch for Set Up of Heat Switches for Manual Valve Addressing)
indoor unit connected to that valve. Recovery Unit Functions)
5. Reset the power to the outdoor unit PCB.
6. The number of the indoor unit installed will be displayed after about five (5) minutes. (Example: Heat Recovery Unit to the Number of the
Indoor Unit.)
7. Reset the power of the outdoor unit PCB and the heat recovery unit.
8. Manual pipe detection addressing is complete.
Figure 31: Manual Pipe Detection Addressing Flowchart.
Execute if auto pipe detection procedure Wait for five (5) minutes.
fails.
Turn No. 1 of DIP switch bank SW02M of The number of the indoor units installed is
heat recovery unit PCB ON.
displayed. Example: Heat recovery unit ĺ
Number of indoor units.
Reset the power of heat recovery unit PCB.
Are the numbers

of indoor units connected to the NO
Enter the central control address into each
outdoor unit and that displayed on
indoor unit using its wired remote control.
the LED the same?
Check the central control addresses
YES of the indoor and heat recovery units.
On the heat recovery unit PCB, manually
set the addresses of each of its valves to
the central control address of the indoor Manual pipe detection is complete. Make sure to reset the power to the
unit connected to that valve. outdoor unit if the central control unit
is changed.
Reset the power to the outdoor unit PCB.
1. If a central controller is not installed yet, leave the address data alone until the installer adds the central controller, and sets the central
control address as desired.
2. If a central controller is already installed, the wired remote controller of the indoor units will provide the central control addresses. (In this
case, manually set the heat recovery unit pipe address following the central control address of the indoor unit.)
3. Central controller addresses must be set manually at each individual controller.
4. A pipe that does not have an indoor unit connected to it must be set with a different address than a pipe that does have an indoor unit
connected to it. (If addresses are the same, the valves will not operate.)
5. Change the manual pipe settings using the heat recovery unit PCB.
6. An error indicates that the manual pipe detection procedure was not completed properly.
7. To save the pipe detection procedure results automatically, do not turn off the main outdoor unit PCB for five (5) minutes after the
procedure has finished.
72
Manual Pipe Detection Example (Non-Zone Setting)

Before performing manual pipe addressing, input a different central control address to every indoor unit through either a wired or a wireless
controller (depending on indoor unit type).
Example: An indoor unit with a central control address of "11” is connected to valve "1" of a heat recovery unit.
No. Display / Setup Description
ON
Operation: None
1 OFF
1 2 3 4
1 2 3 4 Display: None
SSD SW01M SW03M SW04M
ON Operation: Turn DIP switch No. 1 on to address valve No. 1 (SW01M).

2 OFF
1
1
2 3 4
2 3 4
Display: Existing value saved in EEPROM is displayed on LED.
• Operation: Set the “10” digit of the Group High data number of the wired
PCB Settings
ON remote control connected to the corresponding indoor unit to the valve No. 1
3 OFF
1 2 3 4 by pressing left tack switch (SW03M).
1 2 3 4
• Display: Digit increases with the number of times the tack switch is pressed,
shown on left LED numeral.
ON • Operation: Set the “1” digit of the Group Low data number of the wired remote
OFF
1 2 3 4
control connected to the corresponding indoor unit to the valve No. 1 by
4 1 2 3 4 pressing right tack switch (SW04M).
• Display: Digit increases with the number of times the tack switch is pressed;
SSD SW01M SW03M SW04M shown on right LED numeral.
ON
OFF
• Operation: Turn DIP switch No. 1 off to save the address of valve No. 1
5 1
1
2 3 4
2 3 4 (SW01M0
SSD SW01M SW03M SW04M • Display: “11” displayed on LED disappears
• The procedure described above must be performed for all heat recovery unit valves.
• Valves that do not have indoor units connected to them must be addressed with a number that has not been used. (Valves will not work if
the address numbers are the same.)
Manual Pipe Detection Example (Zone Setting)

Zone control is when two (2) or more indoor units are connected to one (1) valve of the heat recovery unit. For this application, set the
controls with the multiple indoor connections using the rotary switch; i.e., only the rotary switch changes the same valve set condition and set
indoor units connection.
1. Set the DIP switch on the corresponding valves and the rotary switch to “0”.
2. Set the number using the tact switches.
3. If additional indoor units are connected to one heat recovery unit valve, increase the rotary switch setting by one (1) and set the number
using the tact switches.
4. To verify the number of the corresponding valve, turn the DIP switch to ON and set the number on the rotary switch.
5. One heat recovery unit valve can support up to eight (8) indoor units per port (rotary switch settings 0~7). An error will display if more than
eight (8) indoor units per heat recovery valve are set with the rotary switch.
6. Return the rotary switch to its original setting (heat recovery unit number settings) after all pipe settings are complete.
7. The rotary switch setting valve of the number of indoor units connected to “FF” prevents a malfunction. Example: Where three (3) indoor
units are connected to valve 1; rotary switch settings are 0,1,2 and 3,4,5,6,7 with “FF” used. (Prerequisite for manual pipe detection: The
central control address of each indoor unit must be preset differently using its wired remote control.)
Example: An indoor unit with a central control address of "11” is connected to valve no. "1" of an heat recovery unit.
ON 0
Operation: None
1 OFF
1 2 3 4
1 2 3 4 Display: None
LED SW01M SW03M SW04M SW05M
ON 0
Operation: Turn DIP switch No. 1 on to address valve No. 1.
2 OFF
1 2 3 4
1 2 3 4 Display: Existing value saved in EEPROM is displayed on LED.
SSD SW01M SW03M SW04M SW05M
ON 0 • Operation: Set the “10” digit to the number in Group High data of the wired
OFF remote control connected to the corresponding indoor unit with the valve No.
1 2 3 4
3 1 2 3 4 1 by pressing left tact switch.
SSD SW01M SW03M SW04M SW05M • Display: Digit increases with the number of times the tact switch is pressed,
shown on left LED.
ON 1
• Operation: Set SW05M to “1”.
4 OFF
1 2 3 4
1 2 3 4 • Display: Former set value is shown on LED.
ON 1
OFF
1 2 3 4 • Operation: Set SW03M, SW04M, and SW05M to “1”.
5 1 2 3 4
• Display: Set value is shown on LED.
ON 1
• Operation: Turn DIP switch No.1 to off to save the address of valve No. 1.
6 OFF
1 2 3 4
1 2 3 4 • Display : Set value from previous step disappears; LED is blank.
ON 0
OFF • Operation: Addressing the return valve of the heat recovery unit.
7 1 2 3 4
1 2 3 4
• Display: LED is blank.
• The procedure described above must be performed for all heat recovery unit valves.
• Valves that do not have connected indoor units must be addressed with a number that has not been used. (Valves will not work if the ad-
dress numbers are the same.)
74
Example of Checking the Valve Address

Example: An indoor unit with a central control address of “11” is connected to heat recovery unit valve No. 1.
ON
OFF • Operation: Turn DIP switch No. 1 to ON.

1 1 2 3 4
1 2 3 4 • Display: “11” displays on SSD.
LED SW01M
ON
• Operation: Turn DIP switch No. 1 to OFF.
2 OFF
1 2 3 4
1 2 3 4
• Display: SSD is blank.
LED SW01M
Identifying the Manual Valve Address

ON
• Operation: More than two (2) DIP switches turned ON.
PCB Settings
OFF
1 1 2 3 4
1 2 3 4 • Display: SSD displays “Er.”
LED SW01M
• Wait for eighty (80) seconds after power is turned ON.

• Zoning and master indoor unit information are removed from EEPROM after auto addressing.
• If a central control is installed, it is impossible to set the master indoor unit in zoning.
TEST RUN
Be aware of the following safety precautions when troubleshooting the main components.
DANGER
• High voltage electricity is required to operate this system. Adhere to the NEC code and these instructions when wiring. Improper connec-
tions and inadequate grounding can cause accidental injury or death.
• Turn the power off before servicing the equipment. Electrical shock can cause physical injury or death.
• Do not operate the disconnect switch with wet hands. There is risk of fire, electric shock, physical injury or death.
• Disconnects must only be performed by a properly licensed electrician. Incorrect wiring could cause the disconnect to explode, leading to
• Do not supply power to the unit until all electrical wiring and controls wiring are completed. There is risk of fire, electric shock, physical
injury or death.
• Do not operate the unit with the panel(s) or protective cover(s) removed; keep fingers and clothing away from moving parts. The rotat-
ing, hot, cold, and high-voltage parts of the unit can cause physical injury or death.
• Do not touch the refrigerant piping during or after operation. It can cause burns or frostbite.
• Do not supply power to the unit until all electrical wiring and controls wiring are completely installed. The system will malfunction.
• If the power wiring and communication cables are not properly connected (connections switched), the communication components will burn
out and the system will not operate.
Test Run Checklist

Table 47: Test Run Checklist.
Check for any refrigerant leaks in the piping system.
1 Verify that all power wiring and communication cables are properly connected. Check for disconnected and loose power wiring and
communication cables connections.
Measure the insulation resistance between the power supply terminal block and ground using a mega-tester device (DC 500V). Resis-
WDQFHPXVWEH0ȍLIWKHUHVLVWDQFHLV0ȍ do not operate the unit.
2 • Never perform the megaohm check on the terminal control board. This will damage the control board.
• Immediately after installation, or if the system is off for a long period, refrigerant can accumulate in the compressor, which can cause
WKHLQVXODWLRQUHVLVWDQFHEHWZHHQWKHSRZHUVXSSO\WHUPLQDOERDUGDQGWKHJURXQGWRGURS0ȍ
,IWKHLQVXODWLRQUHVLVWDQFHLV0ȍWKHSRZHULVWXUQHGRQDQGWKHFRPSUHVVRUFUDQNFDVHKHDWHURSHUDWHVIRUVL[KRXUVWKH
refrigerant evaporates, which will cause the insulation resistance to increase.
For Heat Recovery Systems: Check if the liquid, high pressure vapor, and low pressure vapor piping valves are fully opened.
For Heat Pump Systems: Check if the liquid and vapor piping valves are fully opened.
3
Tighten all caps on the liquid and gas (vapor) service valves.
• Check for any problems in the automatic addressing.
4
• Check / confirm that there are no error messages displayed on the indoor units, wired controllers, or the outdoor unit SSD.
• Main power to the outdoor unit must always remain on during the cooling and heating seasons.
• Apply power after installation, and before performing the test run.
• Always apply power for six (6) hours to heat the crankcase heater before operating the system. The compressor will burn out if the crank-
case heater is not preheated for at least six (6) hours. The compressor will also be damaged if the crankcase heater has not preheated for
DWOHDVWVL[KRXUVDQGWKHV\VWHPRSHUDWHVZKHQWKHRXWGRRUWHPSHUDWXUHLVEHORZ)
76
MAIN COMPONENT ERRORS
Main Component Errors

Table 48: Main Component Errors.
Main component Problem Cause Solution
Motor insulation damaged. Check resistance between terminals and unit frames.
Not operating Strainer is clogged. Clean / change the strainer.
Oil is leaking. Check oil levels.
Compressor After disconnecting the compressor wiring, check
Stopped during operation.. Motor insulation failed.
resistance between terminals and unit frames.
Bad or improper
Abnormal noise during operation. Check compressor connections.
connections.
Check the outdoor unit fan operation after the outdoor
Troubleshooting Main Components

Motor failure, bad
High pressure error when unit unit(s) has(have) been turned off for a while.
Outdoor Unit Fan ventilation around outdoor
operates in cooling mode. If any obstacles are around the outdoor unit heat
unit heat exchanger.
exchanger, switch the outdoor unit OFF and remove.
Heating failure, frequent
Bad connector contact. Check connector.
defrost.
No operation sound after
Coil failure. Check resistance between terminals.
switching on the power.
Outdoor Unit EEV
Heating operation failed; outdoor
unit heat exchanger is frozen.
EEV clogged. Service necessary.
Low pressure error or discharge
temperature error.
• When a system error occurs, the error code is displayed on the indoor unit or the wired control.
• If CH05/53 error occurs, check if auto-addressing is complete and the communication cables are properly installed.
SELF DIAGNOSTICS CHECK
Run Self Diagnostics Check Figure 34: ARUN024~053GSS4 Heat Pump Outdoor Unit Main PCB for
Settings.
Using the DIP Switches DIP-SW01 SSD
• Outdoor unit settings can be checked from the SSD.

• DIP switch settings must only be changed when the power to the
outdoor unit is OFF. SW04C (X : Cancel)
SW03C ( : Forward)
SW02C ( : Backward)
Power to the outdoor unit must be turned off before checking the DIP
switch settings. If not, there is risk of electric shock and physical injury SW01C ( : Confirm)
or death.
SW01D (Reset)
Using the Initial Display
1. Power all indoor units.
2. Verify the outdoor units to indoor units communications cable

is installed and terminated correctly. Inspect terminals on the
outdoor unit.
3. Verify that DIP switches were properly adjusted for the jobsite Figure 33: ARUN60GSS4 Heat Pump Outdoor Unit and ARUB060GSS4
configuration. Heat Recovery Outdoor Unit Service PCB for Settings.
4. Power the outdoor unit.
5. After power is provided to the main printed circuit board (PCB) on
the outdoor unit for five (5) seconds, observe the SSD. SSD
• Wait. The perimeter segments will flash in sequence for IRUW\¿YH
(45) seconds.
SW01C ƔConfirm) SW01D (Reset)
• Verify the microprocessor’s outdoor unit configuration agrees
with the submittal information approved the design engineer SW02C ( : Backward) SW04C (x : Cancel)
(see below).
• Confirm that this step has been completed by checking the SW03C ( : Forward) DIP-SWITCH
box provided on the Record following the information as it is
provided. The date is provided in sequence, and segment of the
sequence will remain lit for two (2) seconds.
Table 49: 'LVSOD\&RGH'H¿QLWLRQV²2XWGRRU8QLW1RPLQDO&DSDFLW\ Table 50: 'LVSOD\&RGH'H¿QLWLRQV²9ROWDJH
Display Code 4 6 8 10 12 14 Outdoor Unit Code 22
Nominal Mb/h 2 4 6 8 10 12 Electrical Requirements 208-230V / 60Hz / 1Ø
Table 51: 6HJPHQW'LVSOD\6HTXHQFH7ZR>@VHFRQGVSHUVHJPHQWIROORZLQJDIRUW\¿YH>@VHFRQGZDLW

Sequence Description Code(s)
1 Nominal Capacity 4 - 14*
Heat Pump 2
2 Unit Type
Heat Recovery 3
3 Unit Voltage 208-230V / 60Hz / 1Ø 22
4 Efficiency Level Standard 1
6HHWDEOHVDERYHIRUFRGHGH¿QLWLRQV
Table 52: Example of Reading the Initial Display: ARUB060GSS4.

Sequence Description Display Code
1 60,000 Btu/h Nominal Capacity 07
2 Unit Type Heat Recovery 3
3 Unit Voltage 208-230V / 60Hz / 1Ø 22
4 Efficiency Level Standard 1
78
CHECKING THE COMPRESSOR
Checking the Compressor

If a compressor error, or any error related to the electrical system has occurred, check for the items below and follow the procedure listed.
Step Number Check for Problem Solution
3RZHUKDVEHHQRQIRUKRXUV Go to Step 2.
How long has power been on during
1 Go to Step 2 after power has been on
operation? 3RZHUKDVEHHQRQIRUKRXUV
for 12 hours.
1. The compressor stops and same error
Check if IPM has failed.
appears again.
2. Inverter output voltage is stable (1). • Check insulation and coil resistors.
Does error occur again after starting
If both are normal, restart the unit. If
operation?
the same error occurs again, replace
the compressor.

Test 1 • ,QVXODWLRQUHVLVWRU0ȍPHD-
Ohm meter testing terminal to terminal sured.
on the compressor. • Coil resistors for Heat Pump and
Comp. Heat Recovery Units.
Tester
GPT442MAA
Temp. 167°F
U-V ȍ
V-W ȍ
W-U ȍ
JBA068MAF
Temp. 77°F 167°F
2 U-V ȍ ȍ
Test 2 V-W ȍ ȍ
W-U ȍ ȍ
Ohm meter testing terminal to pipe
JURXQG7KLVUHDGLQJPXVWEH0 JQA048MAF
Temp. 77°F 167°F
U-V ȍ ȍ
Comp. Pipe V-W ȍ ȍ
Meter W-U ȍ ȍ
JQC048MBC
Temp. 77°F 167°F
U-V ȍ ȍ
V-W ȍ ȍ
W-U ȍ ȍ
3. Inverter output voltage is unstable or • Check the IPM. If normal, replace the
0V (if digital tester is unavailable). inverter board.
• Check coil and insulation resistors.
CHECKING THE OUTDOOR UNIT FAN
:KHQPHDVXULQJYROWDJHDQGFXUUHQWRILQYHUWHUSRZHUFLUFXLWYDOXHVFDQDSSHDUGLႇHUHQWO\GHSHQGLQJRQWRROVDQGFLUFXLWV
because voltage, power supply current, or inverter output has no sine waveform. Output voltage changes when inverter out-
put voltage has a pulse wave pattern.
1. If using a movable tester to check if inverter output voltage is constant (when comparing relative voltage between lines), always use an analog me-
ter. Exercise particular caution if the inverter output frequency is low, when using a tester, where the change of measured voltage values is large
EHWZHHQRWKHUOLQHVZKHQYLUWXDOO\WKHVDPHYDOXHVDSSHDURULQVLWXDWLRQVZKHUHLWFDQEHGLI¿FXOWWRGHWHUPLQHLIDQLQYHUWHUIDLOHG
2. 8VHDUHFWL¿HUYROWPHWHULIXVLQJDFRPPHUFLDOIUHTXHQF\WHVWHUWRPHDVXUHLQYHUWHURXWSXWYDOXHVZKHQPHDVXULQJDEVROXWHYDOXHV

Accurate measuring values cannot be obtained with a general movable tester (for analog and digital mode).
Checking the Outdoor Unit Fan

If there is a fan error, check the items below and follow the corresponding procedure listed.
Check Problem Solution
1. Fan motor is not Power supply is not Check wire connections at the breaker.
operating. (Does correct. Modify the power supply voltage if it is beyond permissible specifications.
fan motor fail • Check wiring connections.
again when opera-
tion starts?) • Check connector contacts.
Wiring is wrong. • Check that all components are firmly secured (tighten screws).
2. Fan motor • Check polarity connection.
vibration is exces- • Check ground wiring and for short circuits.
sive.
80
CHECKING THE ELECTRONIC
EXPANSION VALVES
Checking the Electronic Expansion Valves

Table 53: Pulse Signal Output Value and Valve Operation.
Brown
Output State White
Output (ø) No.
1 2 3 4 Red ø1
Red M
ø1 ON ON OFF ON Blue ø3
Orange
ø2 ON ON ON OFF Orange
ø3 OFF OFF ON OFF Yellow
ø2 ø4
ø4 OFF OFF OFF ON White

Yellow Brown Blue

Output Pulse Sequence
• 9DOYHFORVHVHTXHQFHĺĺĺĺ
• 9DOYHRSHQVHTXHQFHĺĺĺĺ
1. If the EEV open position does not change, output phase will be off.
2. If the output phase is different or continuously on, the motor will start vibrating.
EEV Valve Operation

• At power on, open position signal is 1,400 pulses output, and valve
position is set to "a" (see left). When the valve operates properly,
Valve noise and vibration will not occur. If the valve is closed, noise will
Close be heard.
Open
Position • Noise from EEV can be confirmed by touching the EEV surface
with a screw driver and listening.
Full open • If liquid refrigerant is present in EEV, noise will be lower.
Open
1950 pulses
Pulse
EXPANSION VALVES
Checking the Electronic Expansion Valves, continued.

Figure 35: EEV Coil and Casing (Outdoor Unit).
Casing
Lead Wire
Coil
Figure 36: Removing and Assembling the Coil.

• Power off.
Remove Assemble • Tightly grip the casing, and pull the coil up.
• During assembly, or when the coil is removed, take care not to
bend the casing pipe.
Casing
Casing
82
EXPANSION VALVES
Checking the Electronic Expansion Valves, continued.

Component Problem Diagnosis Solution
1. Remove the EEV connector from the control board, and connect
testing LED.
Check and replace

Microcomputer circuit failure. indoor unit control
board.
1Kȍ LED
2. With main power on, test pulse signal from EEV for 17 seconds.
If LEDs do not turn on, or are continuously on, then the circuit is

incorrect..
Indoor Unit 1. Operate one indoor unit in fan mode, and then operate another indoor
unit in cooling mode.
2. Check the liquid piping temperature of the indoor unit in fan mode
If the amount that
(through the outdoor unit control board).
EEV is closed, but valve is is leaking is
3. Check if the fan is rotating and the EEV is closed. If there is a leak, the
leaking. excessive,
liquid piping temperature at the indoor unit in fan mode will be low.
replace the EEV.
If the measured temperature is very low when compared to the suction
temperature (that is displayed at the remote controller), then the EEV is
not fully closed.
1. Check the resistance between the coil terminals (brown-white,
EEV motor coil has shorted
brown-yellow, brown-orange, brown-blue).
out or has disconnected.
2. If the estimated resistance value is 150±10, then the EEV is normal.
Indoor Unit / Check for a locked EEV: if the system is in a no-load state, if the driving Replace EEV.
EEV locks up.
Outdoor Unit motor is rotating, and a clicking sound can be heard.
1. Check the resistance between coil terminal (red-white, red-yellow,
EEV motor coil has shorted
Outdoor Unit red-orange, red-blue).
out or has disconnected.
2. If the estimated resistance value is 52±3, then the EEV is normal.
CHECKING THE INVERTER IGBTM
Checking the Inverter Insulated-Gate Bipolar Transistor Module

Figure 37: ARUN024GSS4, ARUN038GSS4, ARUN048GSS4, ARUN053GSS4 Heat Pump Inverter IGBTM.
P
U P
V
W VU
W N
N
Figure 38: ARUN060GSS4 Heat Pump Inverter and ARUN060GSS4 Heat Recovery Inverter IGBTM.
P
U
V
CN_U
W CN_V
N CN_W
CN_INPUT_L1
CN_INPUT_L2
P N
1. Shut off main power. After main power is shut off, wait at least ten (10) minutes until inverter compressor PCB DC voltage is discharged.
2. Disconnect DC_Link connector and U, V, W compressor connectors connected to the inverter PCB..
After switching off the main power supply and verifying that the DC voltage was discharged, wait for at least ten (10) minutes before checking the
electrical components in the control box. There is risk of electric shock, physical injury or death.
3. Set the multi-tester to diode mode.

4. Measured value must be 0.2 ~ 0.6 V as shown in the table on the next page.
5. If the measured value is different than what is listed in the table on the next page, then set the multi-tester to resistance mode and mea-
VXUHDJDLQ,IWKHYDOXHLVWRRORZȍRUWRRKLJKKXQGUHGV0ȍWKHLQYHUWHU3&%LVGDPDJHGDQGQHHGVWREHUHSODFHG
6. If the IGBTM is damaged, check if the compressor needs to be replaced.
84
CHECKING THE INVERTER IGBTM AND
+,*+/2:35(6685(6(16256
Checking the Inverter IGBTM, continued.

Table 54: Checking the Inverter IGBTM.
P Terminal: Black (-) N Terminal: Red (+)
U Terminal : Red (+) 0.2 ~ 0.6 V -
V Terminal : Red (+) 0.2 ~ 0.6 V -
W Terminal : Red (+) 0.2 ~ 0.6 V -
U Terminal : Black (-) - 0.2 ~ 0.6 V
V Terminal : Black (-) - 0.2 ~ 0.6 V
W Terminal : Black (-) - 0.2 ~ 0.6 V
Red (+) and Black (-) are the multi-tester terminals.

&KHFNLQJWKH+LJK/RZ3UHVVXUH6HQVRUV
Connect the manifold gauge to the outdoor unit service valve, and compare the high pressure sensor output to the low pressure sensor
output to check for errors. Compare the pressure sensor outputs to the manifold gauge pressure outputs using the table below.
Figure 39: Pressure Sensor Output Characteristics.
Low Pressure Sensor High Pressure Sensor

OUTPUT CHARACTERISTICS OUTPUT CHARACTERISTICS
73 145 218 290 393 435 189 363 551 725 914 1,088
Pressure (psi) Pressure (psi)
1. If the manifold gauge pressure reads 0 to 14.22 psi, it indicates the pressure dropped due to a refrigerant leak. Find the leak and repair
it.
2. If the difference between the high and low pressure outputs is around 14.22 psi, the pressure sensor is normal.
3. If the difference between the high and low pressure outputs is >14.22 psi, the pressure sensor is damaged and needs to be replaced.
Figure 40: Pressure Sensor Schematic. See the pressure sensor schematic at left. DC 5V will to be mea-
sured between red and black wires. DC voltage measured between
High Pressure Sensor : 0~5 MPa (0~725.2 psi) white and black wire corresponds to charts above.
Pressure Vout 0.5~3.5V
Sensor Low Pressure Sensor : 0~2 MPa (0~290.1 psi)
Vout 0.5~3.5V
(Red)
±5%
(White)
(Black)
CHECKING THE OUTDOOR FAN,
FOUR-WAY REVERSE VALVE, AND
TEMPERATURE SENSORS
Checking the Outdoor Fan
1. The inverter motor controls the number of rotations on the outdoor unit fan.
2. The high / low pressure sensors control the outdoor unit fan after compressor operation.
3. Even if the compressor is on, the outdoor unit fan will not operate due to low capacity, or if the outdoor temperature is low. This is normal,
and the outdoor unit fan will begin to operate when the system reaches setpoint.
Checking the Four-Way Reverse Valve

1. The four-way reverse valve must be OFF before the outdoor and Figure 41: Refrigerant Flowchart of the Four-Way Reverse Valve.
indoor units are powered up and turned on.
2. The four-way reverse valve must be OFF during cooling, defrost,
and oil recovery operation. The four-way reverse valve must be
ON during heating operation.

3. When switching from cooling to heating operation, the four-way
valve position changes during the three (3) minute mode change Indoor Heat D : Discharge
Exchanger
restart. Outdoor Heat
Exchanger
Outdoor Heat
Exchanger E : Evaporator
C : Condensor
4. To check if the four-way reverse valve is operating in cooling Heating Operation Cooling Operation S : Suction
or heating mode, touch the piping surface of the low pressure
service valve.
5. See diagram at right for the refrigerant flowchart of the four-way reverse valve.
6. ,QVXODWLRQUHVLVWDQFHEHWZHHQWKHIRXUZD\UHYHUVHYDOYHFRQQHFWLRQDQGWKHFRLOPXVWEH!0ȍPHDVXUHZLWKD'&PHJDWHVWHU>'&
9@
Checking the Temperature Sensors

1. Outdoor Temperature Sensor: TH1
2. Discharge Pipe (D-pipe) Temperature Sensor: TH2
• Check the temperature sensor installation and connections.
• Check if the connection contact of the temperature sensor is normal.
• Measure the resistance of temperature sensor.
3. Pipe Temperature Sensor : TH3
Table 55: Temperature Sensor Resistance Values.
Temperature Sensor TH1 TH2 TH3
Nȍ#) Nȍ#) Nȍ#)
Resistance
Nȍ#) Nȍ#) ȍ#)
86
ERROR CODE GENERAL
INFORMATION
Please refer to the Safety Precautions on pages 4-7 for more detail to prevent injury or death regarding the operation and service
troubleshooting of the Multi V product.
General Information
LG VRF system’s core logic uses error codes to indicate that an abnormal operation occurred. Error codes help guide a trained service tech-
nician to identify why and what caused the error to display, and help track the frequency of malfunction occurrences.
There are four (4) levels of error code responses; the system responds accordingly, depending on the severity of the malfunction assigned to
the malfunction. The level of responses range from “notify and keep operating” (Level 4), to “immediate system shutdown” (Level 1).
All error codes can be viewed at the outdoor unit seven segment display (SSD) and with LGMV software. If an error codes shows on one
(1) or more indoor unit zone controllers, it will display on LGMV, central controllers, BMS, or any other LG device connected to Comm bus -
Internet A/B. Indoor unit error code notifications will display differently based on location of the problem.
Level 4 Responses
Level 4 responses display the error code, but the system continues to operate (operate indefinitely). When the malfunction is fixed, the error
code remains until the master outdoor unit’s microprocessor is reset, and operation has resumed for 130 minutes without the malfunction
reoccurring.
Level 3 Responses
Level 3 responses display the error code on all zone controllers, central controllers, and on BMS systems. For Level 3 responses, the Multi V
system will shut down for three (3) minutes, and then the master microprocessor in the outdoor unit will automatically restart the system.
If the malfunction reoccurs up to a total of nine (9) times within one (1) hour, the system will display the error code, shut down, and restart
Error Codes
again each time. If the malfunction occurs a tenth (10th) time within the same one (1) hour, the system shuts down permanently, assigning
the error to a Level 1 response that requires a manual restart. The error code displays on the zone controllers and central controllers until the
malfunction is fixed.
Level 2 Responses
Level 2 responses are communications related errors only. Level 2 responses activate after ten (10) attempts to communicate have occurred.
After communications have been re-established, the error codes display for one (1) minute. If the communications are restored, then the
error code disappears. If the communication is lost within one (1) minute, the error code remains.
Error codes for Level 2 responses stop appearing on the zone and central controllers as soon as communications are restored, without the
need to reset power at the Master outdoor unit or to restart the entire system.
Multi V error codes for Level 2 responses appear where the problem occurs, and time limits differ depending on type:
1. Communications lost between outdoor unit PCBs – no time delay.
2. Communications lost between the indoor unit and the outdoor unit for three (3) minutes.
3. Communications lost between the indoor unit and heat recovery unit for ten (10) seconds.
4. Communications lost between outdoor unit external PCBs for ten (10) seconds.
Level 1 Responses
Many Level 1 responses call for an immediate system shutdown, and, in almost all abnormal operational situations, occur after the algorithm
monitoring system verifies that the malfunction is real (to avoid nuisance alarms and false positives). Level 1 responses are displayed at
zone controllers, central controllers, BMS, LGMV, and the outdoor unit SSD. They cannot be cleared until the problem that caused it is fixed.
Before a Level 1 response is assigned, the Multi V algorithm initially assigns a Level 3 response to any system malfunction that is not
communications related. The system follows Level 3 protocol until the tenth (10th) time a malfunction occurs, at which time the system shuts
down, the malfunction changes from Level 3 to Level 1, and a manual restart is required. The entire Level 3 auto restart to Level 1 shut down
sequence will repeat until the malfunction is fixed.
For more information on Multi V Levels and error codes, see the troubleshooting pages in this section, and contact an LG trained technician.
ERROR CODE TABLES
Error Code Display

The seven segment display on the main board displays error codes. Figure 42: Example of an Error Code.
Error codes are 3 or 4 digit numbers. The rightmost number desig-
21 1 c1 1
nates the ODU frame (1=Master; 2=Slave1; 3=Slave2). The other
Repeats
two or three digits indicate the error.
Examples: 211 = Error No. 21 on master unit; 212 = Error No. 21 on
slave 1 unit; 213 = Error No. 21 on slave2 unit, 1051 = Error No. 105
Compressor Error
on master unit.
• If two or more errors occur simultaneously, the lower error code Compressor Error
QXPEHULVGLVSOD\HG¿UVW
• After error is resolved, the error code disappears.
Nomenclature Definitions
• MICOM: Non-volatile memory chip where unit setup information is stored.

• ((35201RQYRODWLOHPHPRU\FKLSZKHUHGHYLFHLGHQWL¿FDWLRQVL]HDQGIDFWRU\GH¿QHGGHIDXOWFRPSRQHQWRSHUDWLQJSDUDPHWHUVDUH
stored.
See the error code tables below and on the following pages. Pages after the tables include detailed information for the error codes used for
Multi V systems.
Table 56: Error Codes.

Error Code Description Details
Indoor unit air temperature sensor disconnected or shorted.
Indoor unit return air or optional remote wall temperature
0 1 (Check the wiring, connection on the indoor unit PCB, then check
sensor communications error. the thermistor.)
Indoor unit inlet pipe temperature sensor is disconnected or
Indoor unit inlet pipe temperature sensor communication
0 2 shorted. (Check the connection on the indoor unit PCB, then
error. check the thermistor.)
Communication error between zone controller and indoor Indoor unit PCB is not receiving communications signal from
0 3 unit. zone controller.
Drain pump and/or flow switch is/are malfunctioning. Also check
0 4 Indoor unit drain overflow error. drain line for obstructions.
Communication error between outdoor unit PCB and indoor Indoor unit communications PCB is not receiving signal from out-
0 5 door unit communications PCB for more than 5 minutes. Check
unit PCB. indoor unit PCB for issues.
Indoor unit outlet pipe temperature sensor is disconnected or
Indoor Unit
0 6 Indoor unit outlet pipe temperature sensor error. shorted. (Check the connection on the indoor unit PCB, then
check the thermistor.)
Indoor units are not operating in the same mode. (Heat
0 7 Different operation mode between indoor units.
pump applications only)
• Communication error between the indoor unit PCB board and its
RSWLRQFDUG7KHRSWLRQFDUGLVDERXWƍ[ƍDQGLVSOXJJHGLQWR
the indoor unit PCB board. Check connection between the two.)
0 9 Indoor unit EEPROM error. • Communication error between EEPROM on indoor unit main
PCB.
• Indoor unit EEPROM data is not available.
• Fan motor has been removed or is defective. Refer to the resis-
tance and voltage check charts in this service manual.
• The system has detected the fan motor is not spinning.
1 0 Indoor unit BLDC fan motor communications error.
• On new installs, verify installation manual and paperwork were
removed from fan discharge shroud during installation.
• Check the wiring plug and connections (if applicable).
88
ERROR CODE TABLES
Table 57: Error Codes, continued.

• Refrigerant leak sensor error; sensor is malfunctioning.
• Error will also be displayed if the function is enabled on the
wired remote controller, and there is not a sensor installed.
• Refrigerant leak is detected when >6,000 ppm.
• Enable the function through the function code on the remote
controller.
• Operation stop.
Refrigerant leak sensor error. Only displayed at the • Solenoid valve closes on the indoor unit side.
2 3 0 indoor unit and its wired remote controller. • CH230 is displayed. If the communication baud is 1,200 bps,
then only the zone controller can display the CH230; central
Indoor Unit
controller cannot display the error due to lack of information.

• Buzzer rings 2 long buzzes every 1 second. Ringing stops when
there is an input from the controller. (If there is a hard lock, then
only the controller can make the hard lock to stop buzzing. If
leak sensor measures under 1.5V, then it is considered normal
and the buzzing stops.
• To release the error, power needs reset.
Communication error between outdoor unit PCB and Indoor unit communications PCB is not receiving signal from out-
2 3 7 indoor unit PCB. Only displayed at the indoor unit and door unit communications PCB for more than 3 minutes. Check
its wired remote controller. RS-485 communications for issues.
Communication error between outdoor unit PCB and Indoor unit communications PCB is not receiving signal from out-
Error Codes
2 3 8 indoor unit PCB. Displayed at the indoor unit and its door unit communications PCB for more than 3 minutes. Check
wired remote controller. outdoor unit PCB for issues.
• Overcurrent conditions have been detected at the inverter
compressor (U,V,W).
• Compressor motor or insulation has been damaged.
• IPM has overheated due to damage or disconnection of the
Outdoor unit inverter board IPM fault error. Error code heat sink fan, or the heat sink has been disassembled.
2 1 is determined by overcurrent in any one phase of • Inverter compressor terminal has been disconnected or loos-
ened.
compressor.
• Inverter PCB assembly has been damaged.
• Low input current to the outdoor unit. Damaged inverter board
– input voltage too low. For 208-230V: On 068 compressors =
143A for a minimum of 3μs; on 048 compressors = 96A for a
minimum of 3μs.
• Overcurrent of outdoor unit inverter board PCB.
unit inverter PCB AC input overcurrent (RMS) • Under voltage.
2 2 Outdoor
Outdoor Unit
error. • Refrigerant flow restriction from defective EEV.

• Refrigerant charge is too high (overcharged).
There is a capacitor that is not working properly, or the voltage
at the capacitor is out of range. System shut off because outdoor
unit inverter compressor DC link voltage fell below 50V or ex-
ceeded 550V for a minimum of 250μs.
Low or high DC voltage sensed at the outdoor unit • Start diagnosis at the inverter socket on the outdoor unit noise
2 3 inverter compressor DC link. filter PCB.
• Disconnected DC link.
• Damaged electrical condenser component (serving capacitor)
on inverter driver board. Improper wiring at DC link terminal or
disconnected contact..
Outdoor unit high pressure switch error.
4 System has been turned off by the outdoor unit high • Check the connection on the outdoor unit PCB.
2 pressure switch. • Use chart in Troubleshooting section of the manual to check
signal output (V DC) versus actual pressure.
2XWGRRUXQLWKDVDQLQSXWYROWDJHRI9RU9IRU
2 5 Input voltage to the outdoor unit is too high or too low. 230V units).
2 6 Outdoor unit inverter compressor operation error. Inverter compressor failed to start.
ERROR CODE TABLES

• Outdoor unit inverter compressor current draw is too high.
2 9 Outdoor unit inverter compressor overcurrent error. • Compressor defect and restriction in refrigerant piping are
possible causes.
• System shutdown happens when discharge pipe temperature
rises >115°C (239°F) for 10 seconds, or compressor tempera-
ture equals 105°C (221°F) for 10 seconds.
Excessive increase in outdoor unit inverter compressor gas • Check the inverter compressor discharge pipe temperature
3 2 sensor.
discharge temperature.
• Check for low refrigerant / leaks.
• Check for a defective EEV.
• Check for a defective liquid spray valve.
• Shutdown due to if compressor high pressure is >4,000 kPa

(580 psi) for ten (10) seconds.
• Check the high pressure sensor, indoor unit or outdoor unit
3 4 Outdoor unit compressor high pressure safety tripped. fan(s), refrigerant, EEV, service valve (can be clogged); check
for defective outdoor unit PCB, indoor unit pipe temperature
sensor, or hot gas valve. Also, outdoor unit could not have
enough clearance (cooling operation), or indoor unit filter can
be clogged (heating operation).
• System will shut down when an abnormal low pressure condi-
tion occurs.
• Shut down occurs when the compressors inverter frequency
<30Hz = low <110 kPa for 1 minute.
• When operating in cooling mode: Low side pressure <400
3 5 Outdoor unit low side pressure below allowable limits. kPa for 1 minute; High side pressure is <2,200 kPa. Check for
refrigerant leaks (low refrigerant charge), or a defective indoor
Outdoor Unit
unit EEV.
• When operating in heating mode: Low side pressure <230
kPa for 1 minute; High side pressure is <1,800 kPa. Check
for refrigerant leaks (low refrigerant charge), or a defective
outdoor unit EEV.
• Outdoor unit is experiencing a problem developing compressor
lift. Error is calling out low compression ratio. System will shut
down and display error code “CH36”.
• Error occurs if the compression ratio is <1.6 (scroll compres-
3 6 Outdoor unit inverter low compression ratio. sor) or <1.8 (rotary compressor) for 2 minutes following a
change in position of the reversing valve (either direction), and
for 5 minutes following a compressor start.
• Pressure differential: <400kPa (scroll compressor), and
500kPa (rotary compressor).
Outdoor unit inverter compressor current transducer (CT) Outdoor unit inverter compressor current transducer (CT) detec-
4 0 sensor error. tion sensor disconnected or shorted.
• Error can also occur if the system is operating in cooling at
extremely low temperatures with no low ambient kit.
• Compressor discharge pipe temperature sensor (TH3) is not
installed or connected properly.
• Defective compressor discharge pipe sensor (TH3) (opened or
Outdoor unit inverter compressor discharge pipe temperature shorted).
4 1 • Defective outdoor unit PCB.
sensor error.
• Standard values of sensor resistance at different temperatures
YDULDWLRQ°) Nȍ°) Nȍ°F = 82
Nȍ°) Nȍ
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90
ERROR CODE TABLES

• Check the connection on the outdoor unit PCB.
4 2 Outdoor unit low pressure sensor error.
• Thermistor shorted or opened.
• Check for 12 V DC between 12 V and GND (red to black) for 5
V DC.
4 3 Outdoor unit high pressure sensor error. • Check the Signal to GND (white to black) and use correct chart
from Troubleshooting section to compare with actual system
pressure.
4 4 Outdoor unit ambient temperature sensor error. • Check the connection on the outdoor unit PCB.
4 5 Outdoor unit heat exchanger pipe temperature sensor. • Thermistor shorted or opened.
4 6 Outdoor unit suction pipe temperature sensor error. • Thermistor shorted or opened.
• Check suction sensor in cooling mode; check hot gas sensor
located near the heat exchanger in heating mode.
5 0 Outdoor unit loss of phase. Input power line connection is / are missing for the outdoor unit.
The total of the nominal indoor unit capacity is less than 50% or
5 1 Combination ratio is out of range. more than 130% of the nominal outdoor unit capacity.
• Communication error between main PCB and inverter PCB.
Communication error between outdoor unit main PCB
5 2 • Check connections at both sockets.
and inverter PCB.
Outdoor Unit
Error Codes
• Inspect interconnecting cable for wear.
• Check if outdoor unit to indoor unit(s) communications cable
Communication error between outdoor unit main PCB disconnected or shorted.
5 3
and indoor unit(s) PCB. • Check A terminals are connected to indoor unit A(3) (5 on 3 x 3
cassette) terminals; B(4) (6 on 3 x 3 cassette) terminals.
Outdoor unit main PCB and inverter PCB communica- Outdoor unit inverter PCB is not receiving signal from main
5 7
tion error. PCB.
• Verify the EEPROM is present and in the socket correctly.
• Check if all pins are in and are not bent.
6 0 Outdoor unit inverter PCB EEPROM error.
• Check if notch in the chip lines up with the arrow on the
socket.
System shut off because of high temperatures at the outdoor
6 2 High temperature at the outdoor unit inverter heat sink.
unit inverter heat sink.
Outdoor unit inverter heat sink temperature sensor • Check for 12 V DC between 12 V and GND (red to black) for 5
6 5 V DC.
error.
• Check the Signal to GND (white to black) and use correct chart
from Troubleshooting section to compare with actual system
temperature.
6 7 Outdoor unit fan has locked up. No airflow.
7 1 Outdoor unit inverter CT sensor error. Outdoor unit is restricted.
• Verify the EEPROM is present and in the socket correctly.
• Check if all pins are in and are not bent.
8 6 Outdoor unit main PCB onboard EEPROM error.
• Check if notch in the chip lines up with the arrow on the
socket.
ERROR CODE TABLES

1 1 3 Outdoor unit liquid pipe temperature sensor error.
• Check for 12 V DC between 12 V and GND (red to black) for
1 1 4 Outdoor unit subcooling inlet temperature sensor error. 5 V DC.
• Check the Signal to GND (white to black) and use correct chart
Outdoor unit subcooling outlet temperature sensor from Troubleshooting section to compare with actual system
1 1 5
error. temperature.
Code indicates that based on current superheat measurements,
there is a high possibility of liquid refrigerant flooding back and
damaging the compressor.
• Outdoor unit compressor discharge superheat not satisfied for
Outdoor Unit
PLQXWHV
• Code can only occur when the outdoor is operating in cooling

mode (all indoor units must be in cooling mode; error cannot
occur during simultaneous operation).
Outdoor unit compressor discharge superheat not • After at least 10 minutes of compressor operation, the master
1 5 0 outdoor unit microprocessor will calculate the system’s com-
satisfied. (ARUN / ARUB60GSS4 only)
pressor superheat. If at any time during compressor operation
where all indoor units in thermal on are in cooling mode and
the compressor superheat falls <4.8°F&IRUPLQXWHV
there is a high probability that liquid could flood back to the in-
let of the compressor scroll, resulting in compressor damage.
• If error occurs 3 times within any 1 hour period of compressor
operation, the system will shut down and remain off. A manu-
al restart will be necessary.
The difference between the high and low pressure is Not enough pressure difference between high and low. Function
1 5 1
too low. error of outdoor unit four-way reversing valve.
92
ERROR CODE TABLES

The amount of nominal cooling capacity of indoor units con-
nected to a heat recovery unit, or a heat recovery unit port, or
grouped heat recovery unit port is excessive. After auto-pipe
detection is complete, wait 5 minutes, then verify connected
capacity. System will display error if:
• The heat recovery unit port addresses are all unique, then >54
Mbh single indoor unit connected; >54 Mbh total of multiple
indoor units connected.
C+
No. Capacity of indoor units connected to the heat • If 2 heat recovery unit port addresses are the same and the
- 5 1 of HR ports are twinned; >108 Mbh total of multiple indoor units are
recovery unit exceeds allowable limits.
Unit connected.
• If 3 heat recovery unit port addresses are the same and the
ports are all connected, >162 Mbh total of multiple indoor
units connected.
• If the total connected indoor unit nominal capacity exceeds
192 Mbh for a single heat recovery unit.
• Error code displays on the outdoor unit SSD, the heat recov-
ery unit SSD, or in LGMV.
Error Codes
2 0 0 1 Auto pipe search failure. Auto piping procedure did not complete properly.
Heat Recovery Unit
Heat recovery unit liquid sensor error. (C = Heat Disconnection or short circuit of heat recovery unit liquid pipe
2 0 1
recovery unit + Heat recovery unit number). sensor.
Heat recovery unit subcooling pipe inlet sensor
Disconnection or short circuit of heat recovery unit subcooling
2 0 2 error. (C = Heat recovery unit + Heat recovery unit
pipe inlet sensor.
number).
Heat recovery unit subcooling pipe outlet sensor
Disconnection or short circuit of heat recovery unit subcooling
2 0 3 error. (C = Heat recovery unit + Heat recovery unit
pipe outlet sensor.
number).
Communication error between outdoor unit and
2 0 4 heat recovery unit. (C = Heat recovery unit + Heat Outdoor unit does not receive signal from heat recovery unit.
recovery unit number).
C+
No. Communication error between heat recovery unit
• Communication problem occurred between the heat recovery
of HR (2A Series) and the 485 modem. The 2A Series heat
Unit unit PCB and the connection to the communications bus.
recovery unit applies only to heat recovery systems
2 0 5 • Error displays if the outdoor unit signal is not received for
communicating at a baud rate of 9,600 bps.
three (3) minutes. The error clears after the signal is received
• The 485 modem is the communications style on
from the modem. (2A Series Heat Recovery Units.)
the bus that is 1e outdoor unit to many indoor units.
Duplicate address error of the heat recovery unit
• A heat recovery unit address is duplicated for 485 communi-
(2A Series).
cation.
• The 2A Series heat recovery unit applies only to
• There are two heat recovery units with one or more HEX
2 0 6 heat recovery systems communicating at a baud
addresses that are the same.
rate of 9,600 bps.
• Adjust the hex address dial found on the heat recovery units.
• The 485 modem is the communications style on the
bus that is 1e outdoor unit to many indoor units.
Network
Inability of the central controller to receive information from the

2 4 2 Network error of central controller.
outdoor unit.
ERROR CODES
Error Nos. 01, 02, 06
Error No. Description Details Causes

Indoor unit return air or optional remote
01 wall temperature sensor communica-
tions error. 1. Problem with the sensor.
Sensor has disconnected or short cir- 2. Connections on indoor unit PCB are
Indoor unit inlet pipe temperature sen- cuited. Use the OHM and voltage check
02 charts. wrong.
sor communication error.
3. Indoor unit PCB has failed.
Indoor unit outlet pipe temperature
06
sensor error.
Is the sensor properly connected to No

Connect to the PCB properly.

the PCB?
Yes
Is the resistance value of the sensor No

Change the sensor.
normal?
Yes
Replace the PCB.
• ,IWKHYDOXHLV!NȍRSHQRUȍVKRUWWKHUHLVDQHUURU

• Sensor resistance value will vary with the temperature. See below for the resistance values according to temperature (±5% tolerance).
• $LUWHPSHUDWXUHVHQVRU) Nȍ) Nȍ) Nȍ
• 3LSHWHPSHUDWXUHVHQVRU) Nȍ) Nȍ) Nȍ
CN-ROOM: Indoor Air Temperature Sensor

CN-PIPE IN: Pipe Inlet Temperature Sensor
CN-PIPE OUT: Pipe Outlet Temperature Sensor
Measure the resistance of outlet pipe temperature

sensor.
Images here are representative

of system components. Actual
component appearance depends
on model and system type.
94
ERROR CODES
Error No. 03

1. Zone controller error.
2. Indoor unit PCB error.
Communication error between zone Indoor unit PCB has not received com-
03 3. Connection error or connection
controller and indoor unit munications signal from zone controller.
wrong.
4. Transmission cable error.
Does the error happen again after No

Replace the controller.
the controller is replaced?1
Yes
Does the error occur after the con- No Check the communications cable and the
troller cable is replaced? connection.2
Yes
Replace the indoor unit PCB.3
Error Codes
1
If there isn't a controller to replace, use an operating controller from another indoor unit.
2
Plug the controller directly into the indoor unit PCB. If the error code does not come back after several minutes, the cable needs to be replaced.
Check the cable because the connection could be in error. Check for cable extensions. Also, check distances between the communication cable and
main electrical wiring. Ensure that the cable and wiring are at safe distances from one another to avoid being affected by electromagnetic waves.
3
After replacing the indoor unit PCB, perform the auto addressing procedure, and input unit address if system includes a controller. (All
connected indoor units must be turned ON before initiating the auto addressing procedure.)

CN-REMO: Remote controller connection
The PCB can differ from model to model.
Checking communication cable connection
ERROR CODES
Error No. 04

1. Drain pump / float switch error.
Drain pump and / or float switch is / are 2. Improper drain pipe location, clogged drain
Indoor unit drain
04 malfunctioning. Also check if the drain line is
overflow error. pipe.
obstructed.
3. Indoor unit PCB error.
Is the drain pan filled half- No Is the float switch No

way with water? (Float is halfway resistance short when Replace the float switch.
up to the float switch.) measured?
Yes
Replace the indoor unit PCB or reconnect the
Yes
connector.
Is the drain pump No For the indoor unit No

operating? (Sound / drain noise / PCB, does the voltage have Replace the indoor unit PCB.
contact / etc.) the correct output?
Yes Yes
Replace the drain pump.
No
Check the height and slope of the
Is the drain pump clogged?
drain head.
Yes
Remove any debris and clean the pump.

* If the float rises higher than half its on model and system type.
height, then the circuit opens and the
unit automatically stops.
96
ERROR CODES
Error No. 04, continued.
Float
A: Point to Check Rotation ** Indoor PCB Drain Pump Connector

(Check Electrical Input; Marked as
CN-DPUMP
Error Codes
Float Switch Housing (CN-FLOAT)
Images here are representative of system components. Actual compo-

nent appearance depends on model and system type.
Standard Drain Pipe Height / Slope.
Maximum 1/50~1/100
11-13/16 inches inches
Maximum
27-1/2 inches
ERROR CODES
Error No. 05

1. Auto addressing has not been performed
properly.
2. Communication cable is not connected.
Communication Indoor unit PCB is not receiving communica- 3. Communication cable is short circuiting.
error between out- tions signal from outdoor unit PCB for more
05 4. Indoor unit communication circuit error.
door unit PCB and than 5 minutes. Check indoor unit PCB for
indoor unit PCB. issues. 5. Outdoor unit communication circuit error.
6. Not enough physical distance between pow-
er wiring and communication cables.
7. T-phase line disconnection.
Replace the PCB of indoor unit after

No After auto addressing, is No error is displayed.
Do all the indoor units the correct number of indoor
display error code CH05? units connected displayed? Reconnect after checking the
communication cable of the indoor
Yes Yes unit that displays the error.
END
Check and replace the outdoor unit
No Is the power supply at No PCB.
Is the outdoor unit the outdoor unit terminal
PCB LED blinking? block correct?
Check and replace TRANS.
Yes
Yes
Check the insulation of the inverter
No compressor; replace if necessary.
Is the main circuit breaker OFF?
Check the capacity of main circuit
Yes breaker; replace if necessary.
Power supply cable is not connected properly. Check the T-phase connection.
There is a problem with the main power supply. If the above are operating correctly,
turn on main circuit breaker.
Check if the
communication cable is
properly connected No
Reconnect communication cable.
to indoor / outdoor unit
terminal blocks?
Outdoor unit PCB is malfunctioning. Images here are representative
Yes
Check, then replace. of system components. Actual
Indoor unit PCB is malfunctioning.
Check, then replace.
Communication from the indoor unit is normal if voltage If the DC voltage between communication terminal A, B
fluctuation (-9V ~ +9V) exists (when checking DC voltage of the of indoor unit fluctuates within -9V ~ +9V, then the
communication terminal between the indoor and outdoor units). communication from the outdoor unit is normal.
See also Error Code No. 237:

RS-485 Communication Error
Between Indoor Unit and Outdoor
Unit, and Error Code No. 238:
Outdoor Unit PCB Communication
Error Between Indoor Unit and
Outdoor Unit.
98
ERROR CODES
Error No. 09

• Serial number on
EEPROM of indoor
unit is 0 or FFFFFF.
• Communication error 1. Error developed in transmission between the microproces-
09 Indoor unit EEPROM error. between MICOM and sor and the EEPROM on the indoor unit PCB.
EEPROM. 2. EEPROM is damaged.
• Indoor unit PCB EE-
PROM is in error or
data is not available.
Replace the indoor unit PCB, perform the Auto Addressing procedure, and input the central control address.
Error Codes
ERROR CODES
Error No. 10

1. Fan motor connector has disconnected,
Indoor unit BLDC removed, or malfunctioned.
Indoor BLDC fan motor feedback signal has
10 fan motor commu-
been absent for at least 50 seconds. 2. Indoor fan motor lock has failed.
nications error.
3. Indoor PCB error.
Is the connection No
installed properly? Connect properly.
Yes
Is fan motor No
Replace indoor unit fan motor.
operating normally?*
Yes
Replace indoor unit PCB**
*The indoor unit fan motor hall sensor is operating normally when the values measured are as shown below.
Measure Each Terminal with the Tester

Tester
Normal Resistance (±10%)
+ -
1 4
5 4 Hundreds kȍ +XQGUHGVNȍ
k
6 4
7 4 Hundreds kȍ +XQGUHGVNȍ
1 4 5 6 7
Checking the Fan Motor Connections

** Replace the indoor unit PCB, perform the Auto Addressing procedure, and then input the
central control address.
Check the fan motor connection to the PCB only when power is OFF. Electrical shock can cause physical injury or death.
100
ERROR CODES
Error No. 21

• IPM has overheated, 1. Overcurrent conditions have been detected at the inverter compressor
or has been subject- (U,V,W).
ed to overcurrent 2. Compressor motor or insulation has been damaged.
or undercurrent
conditions. 3. IPM has overheated due to damage or disconnection of the heat sink fan, or the
Outdoor heat sink has been disassembled.
• IPM protection circuit
unit inverter 4. Inverter compressor terminal has been disconnected or loosened.
21 has been activated.
board IPM 5. Inverter PCB assembly has been damaged.
fault error. • Inverter driver
detects overcurrent; 6. Low input current to the outdoor unit.
Error code is deter- 7. Damaged inverter board – input voltage too low. For 208-230V: On 068 com-
mined by overcurrent
in any one phase of pressors = 143A for a minimum of 3μs; on 048 compressors = 96A for a mini-
compressor mum of 3μs.
No
Are the power wiring
&KHFNWKHZLULQJFRQQHFWLRQVĺ5HZLUHLIHUURUVDUHIRXQG
connections correct?
1. Check resistance between each compressor terminal.
Yes
JQC048MBC JBA068MAF
Are the resistance be- Temp. 77°F 167°F Temp. 77°F 167°F
No U-V ȍ ȍ U-V ȍ ȍ
Error Codes
tween each phase and the
insulation resistance of the invert- V-W ȍ ȍ V-W ȍ ȍ
W-U ȍ ȍ W-U ȍ ȍ
er compressor correct?
JQA048MAF GPT442MAA
Temp. 77°F 167°F Temp. 167°F
U-V ȍ ȍ U-V ȍ
V-W ȍ ȍ V-W ȍ
See the “Checking the Inverter Insu- W-U ȍ ȍ W-U ȍ
Yes
lated-Gate Bipolar Transistor Module”
page in the “Troubleshooting Main 2. Check insulation resistance between compressor terminal and
Components” section. SLSLQJ!0ȍ
ĺ5HSODFHFRPSUHVVRULISUREOHPVDUHIRXQG
No 1. Check inverter PCB assembly and U, V, W connections.

Are the compressor wiring
connections correct? 2. Check wiring for any disconnections or damage.
See the “Checking the 3. Check compressor terminal connections for bad contacts.
Inverter Compressor Yes ĺ5HDVVHPEOHLIHUURUVDUHIRXQG
Phase Diode Bridge” No
page later in this Are the DC Link wiring 1. Check inverter PCB assembly and P, N connections.
section. connections correct?
2. Check wiring for any disconnections or damage.
Yes ĺ5HDVVHPEOHLIHUURUVDUHIRXQG
Are the compressor No
IPM heat sink’s connections Check inverter PCB IPM heat sink connections.
correct? ĺ5HDVVHPEOHLIHUURUVDUHIRXQG
Always apply heat
transfer paste to the Yes
new inverter PCB No Check if inverter PCB IPM is operating normally.
heat sink before Is the inverter PCB operat-
ing correctly? ĺ5HSODFHFRPSUHVVRU3&%DVVHPEO\LIHUURUVDUHIRXQG
installing. For instruc-
tions, see “Replacing
the Inverter PCB Heat Yes
sink” page later in this
section. Recheck power and installation.
ERROR CODES
Figure 43: ARUN024 to 053GSS4 Error No. 21 Compressor Terminal and Wiring Connections.
Measuring the resistance between Compressor wiring connections.
compressor terminal.
Figure 44: ARUN060GSS4 and ARUB060GSS4 Error No. 21 Compressor Terminal and Wiring Connections.
compressor terminals.
Images here are representative of system components. Actual component appearance depends on model and system type.
102
ERROR CODES
Error No. 22

1. Overload: Pipe has been clogged, EEV is de-
fective, indoor or outdoor unit is blocked, there
has been an overcharge in refrigerant.
Outdoor unit The input power current for the inverter PCB 2. Compressor motor or insulation has been
22 AC inverter board assembly is >30A (ARUN024 ~53GSS4) or damaged.
input overcurrent
(RMS) error. >38A (ARUN060GSS4 and ARUB060GSS4). 3. Input voltage is low.
4. Improper connections in the power wiring.
5. Inverter PCB assembly has been damaged
(input current sensor).
1. Check if any pipes are clogged or have been damaged.

No 2. Check if the indoor unit or outdoor unit air flow is blocked.
Is the installation correct? 3. Check EEV connection assembly is correct and operating
normally.
Yes 4. Check refrigerant pressure.
See the “Checking the In-
Error Codes
ĺ5HDVVHPEOHLIHUURUVDUHIRXQG
verter Insulated-Gate Bipo-
lar Transistor Module” page
in the “Troubleshooting Main
Components” section. Are the resistance be-
No 1. Check resistance between each compressor terminal.
2. Check insulation resistance between compressor terminal
insulation resistance of the invert-
DQGSLSLQJ!0ȍ
er compressor correct?
ĺ5HSODFHFRPSUHVVRULISUREOHPVDUHIRXQG
See the “Checking the Yes

Inverter Compressor 1. Check inverter PCB assembly and U, V, W connections.
No
Phase Diode Bridge” Are the compressor wiring 2. Check wiring for any disconnections or damage.
page later in this connections correct?
section. 3. Check compressor terminal connections for bad contacts.
Yes
Is the inverter PCB No Check inverter PCB and bridge diode connections.
bridge diode connections
Always apply heat
transfer paste to the Yes
new inverter PCB
heat sink before No Check if L - N phase are 220V ±10%.
installing. For instruc- Is the input voltage normal?
tions, see “Replacing ĺ&KHFNZLULQJDQGFRQQHFWLRQVLISRZHULVDEQRUPDO
the Inverter PCB Heat
Sink” page later in this Yes
section. No
Is the inverter PCB operat- Check if inverter PCB IPM is operating normally.
ing correctly? ĺ5HSODFHFRPSUHVVRU3&%DVVHPEO\LIHUURUVDUHIRXQG
Yes
Recheck power and installation.
ERROR CODES
Measure resistance between each
compressor terminal. Measure input voltage.
Images here are representative of system
components. Actual component appearance
depends on model and system type.
Compressor wiring connections.
compressor terminal. Measure input voltage. Compressor wiring connections.
104
ERROR CODES
Error No. 23

1. DC link terminal disconnection or terminal contact fault.
System shut off because 2. System shut off because outdoor unit inverter compressor DC
Low or high DC DC voltage has not
voltage sensed at link voltage fell below 50V, or exceeded 550V for a minimum of
charged, or because of an 250μs.
23 the outdoor unit
inverter compres- overcurrent in the outdoor
3. Condenser is damaged.
sor DC link. unit inverter PCB DC link
voltage. 4. Inverter PCB assembly is damaged (DC Link voltage sensor).
5. Improper input voltage or power wiring.
No Check if L - N phase voltage is <180V or >253V.

Is the input voltage correct?
ĺ&KHFNFRQQHFWLRQVDQGZLULQJLISRZHULVQRWFRUUHFW
Yes
Are the inverter PCB No Check the connections from the terminal block to the
assembly power connections inverter PCB assembly.
Error Codes
correct? ĺ5HZLUHLIHUURUVDUHIRXQG
Yes
No Check inverter assembly.
Is the inverter PCB assem-
bly correct? ĺ5HSODFHLQYHUWHU3&%DVVHPEO\LISUREOHPVDUHIRXQG
Yes
See the “Checking the Inverter Insulated-Gate Bipolar Transistor Module” and the “Checking the Phase Diode Bridge” pages in the “Troubleshooting
Main Components” section.
Always apply heat transfer paste to the new inverter PCB heat sink before installing. For instructions, see “Replacing the Inverter PCB Heat sink”
page later in this section.
ERROR CODES
Error No. 24

1. Outdoor unit high pressure switch is defective.
2. Indoor unit fan or outdoor unit fan is / are defective.
3. Compressor check valve is clogged.
4. Pipe has been damaged.
5. Overcharge of refrigerant.
Outdoor unit high pressure switch
System has been error. Excessive increase in 6. Defective EEV at the indoor or outdoor unit.
turned off by the outdoor unit compressor discharge 7. Outdoor unit is blocked during cooling mode; indoor
24 outdoor unit high pressure. unit filter is clogged during heating mode.
pressure switch. 8. Service valve is clogged.
9. Outdoor unit PCB is defective.
10. Check connection on the outdoor unit PCB.
11. Active path valve is defective.
12. Use chart in Troubleshooting section of the manual to

check signal output (V DC) versus actual pressure.
Is the high pressure No

switch connected to Securely connect.
the PCB?*
Yes
Has the high pressure No Has the high pressure No

switch shorted out when the switch terminal shorted Replace high pressure switch.
system wasn’t operating?** out?**
Yes *ARUN024~053GSS4 high pressure
Yes switch connection on Main PCB.
Replace connection cable.
No
Is the service valve open? Open the service valve.
Yes
Does the error reappear No Recheck--was the problem

after the system is reset? temporary?
*ARUN060GSS4 / ARUB060GSS4 high
Yes
pressure switch connection on Main PCB.
Is the high pressure No

>2500 kPa (measured at Replace PCB.
the manifold gauge)?
Yes
Does the high pressure

measured at the manifold No
Replace the high
gauge match LGMV data?
pressure sensor.
Yes
**Check if the high pressure switch
Check if piping is blocked connection has shorted out.
and fix as necessary.
Images here are representative of system

components. Actual component appearance
depends on model and system type.
106
ERROR CODES
Error No. 25

Input voltage to 1. Input voltage is abnormal.
the outdoor unit Outdoor unit has an input voltage of <180V 2. Outdoor unit inverter PCB assembly is
25
is too high or too or >253V. damaged (input voltage sensor component).
low. 3. A phase line is disconnected.
No
Are the power wiring Check wiring connections.
connections correct? ĺ5HZLUHLIHUURUVDUHIRXQG
Yes
No
Is the input voltage Check if phase voltage is <180V or >253V.
normal? ĺ&KHFNFRQQHFWLRQVDQGZLULQJLISRZHULVQRWFRUUHFW
Yes
Error Codes
Are the Inverter No
PCB assembly phase Check the phase bridge diode and inverter PCB connections.
bridge diode connections ĺ:LUHDJDLQLIHUURUVDUHIRXQG
correct?
Yes
No 1. Check inverter PCB connections.

Are the DC link wiring connec-
2. Check wiring and wiring connections.
tions correct?
ĺ5HZLUHLIHUURUVDUHIRXQG
Yes
No
Does the Inverter PCB LED
Replace Inverter PCB.
display an error?
Yes
ERROR CODES
Error No. 26

1. Overload error: Piping is clogged, indoor or
outdoor unit is blocked, EEV is defective, or
there is an overcharge in refrigerant.
Outdoor unit in- 2. Compressor insulation and / or motor has
26 verter compressor Inverter compressor start failure.
operation error. been damaged.
3. Compressor wiring error.
4. Outdoor unit inverter PCB has been dam-
aged (CT).
1. Check if piping is clogged or has been damaged.

2. Check if outdoor or indoor units are blocked.
No
Is the installation correct? 3. Check if EEV is operating normally and the connections are correct.
4. Check the refrigerant pressure.
Yes ĺ5HLQVWDOORUIL[LIHUURUVDUHIRXQG
No
Are the power wiring Check wiring connections.
connections correct? ĺ5HZLUHLIHUURUVDUHIRXQG
Yes 1. Check the resistance between each compressor terminal.

JQC048MBC JBA068MAF
Is the resistance be- Temp. 77°F 167°F Temp. 77°F 167°F
No U-V ȍ ȍ U-V ȍ ȍ
V-W ȍ ȍ V-W ȍ ȍ
inverter compressor insulation
W-U ȍ ȍ W-U ȍ ȍ
resistance correct?
JQA048MAF GPT442MAA
Yes Temp. 77°F 167°F Temp. 167°F
U-V ȍ ȍ U-V ȍ
V-W ȍ ȍ V-W ȍ
See the “Checking the W-U ȍ ȍ W-U ȍ
Inverter Insulated-Gate
Bipolar Transistor Mod-
ule” and the “Checking
2. Check insulation resistance between compressor terminal and pipe
the Phase Diode Bridge”
pages in the “Trouble- !ȍ0
shooting Main Compo- ĺ5HSODFHFRPSUHVVRULIHUURUVDUHIRXQG
nents” section.
1. Check Inverter compressor PCB assembly, U,V,W connections.
No
Are the compressor wiring 2. Check if the wires have disconnected or were damaged.
connections correct? 3. Check compressor terminal connections for bad contacts.
Yes
No Check if Inverter compressor PCB assembly and IPM are correct.
Is the inverter
compressor PCB assembly ĺ5HSODFHFRPSUHVVRU3&%DVVHPEO\LIHUURUVDUHIRXQG
correct?
Yes
Always apply heat transfer paste to the new inverter PCB heat sink before
Recheck power and installation. installing. For instructions, see “Replacing the Inverter PCB Heat sink” page
later in this section.
108
ERROR CODES
compressor terminal.

Error Codes
compressor terminals.
ERROR CODES
Error No. 29

1. Overload operation (piping is clogged,
indoor or outdoor unit is blocked, EEV is
Outdoor unit defective, refrigerant is overcharged).
inverter 2. Compressor insulation and / or motor is /
29 Inverter compressor input current is >30A.
compressor are damaged.
overcurrent error. 3. Input voltage is low.
4. Outdoor unit Inverter PCB assembly is
damaged.
1. Check if piping is clogged or has been damaged.

No
Is the installation correct? 2. Check if outdoor or indoor units are blocked.
3. Check the EEV connector assembly and verify it is operating normally.

Yes 4. Check the refrigerant pressure.
ĺ5HLQVWDOORUIL[LISUREOHPVDUHIRXQG
1. Check the resistance between each compressor terminal.
JQC048MBC JBA068MAF
Temp. 77°F 167°F Temp. 77°F 167°F
Are the resistance No U-V ȍ ȍ U-V ȍ ȍ
between each phase and the
V-W ȍ ȍ V-W ȍ ȍ
inverter compressor insulation
W-U ȍ ȍ W-U ȍ ȍ
resistance correct?
JQA048MAF GPT442MAA
Temp. 77°F 167°F Temp. 167°F
U-V ȍ ȍ U-V ȍ
See the “Checking the V-W ȍ ȍ V-W ȍ
Inverter Insulated-Gate
W-U ȍ ȍ W-U ȍ
Bipolar Transistor
Module” page in the
2. Check insulation resistance between compressor terminal and pipe
“Troubleshooting Main
Components” section. !ȍ0
ĺ5HSODFHFRPSUHVVRULIHUURUVDUHIRXQG
Yes
1. Check Inverter compressor PCB assembly, U,V,W connections.
No
Are the compressor wiring 2. Check if the wires have disconnected or were damaged.
connections correct? 3. Check compressor terminal connections for bad contacts.
Yes
No
Check if phase voltage is <180V or >253V.
Is the input voltage normal?
ĺ&KHFNFRQQHFWLRQVDQGZLULQJLISRZHULVQRWFRUUHFW
Yes
No Check if Inverter compressor PCB assembly and IPM are correct.
Is the compressor PCB ĺ5HSODFH,QYHUWHUFRPSUHVVRU3&%DVVHPEO\LIHUURUVDUHIRXQG
assembly correct?
Yes Always apply heat transfer paste to the new inverter PCB heat sink before
installing. For instructions, see “Replacing the Inverter PCB Heat sink” page
Recheck power and installation. later in this section.
110
ERROR CODES
compressor terminal. Measure input voltage. Images here are representative
Error Codes
compressor terminal. Measure input voltage. Compressor wiring connections.
ERROR CODES
Error No. 32

1. System shutdown happens when discharge
pipe temperature rises >115°C (239°F) for
10 seconds, or compressor temperature
Excessive increase equals 105°C (221°F) for 10 seconds.
in the discharge System / compressor shut off because of a 2. Defective compressor discharge piping
32 temperature at the high discharge temperature at the outdoor temperature sensor.
outdoor unit inverter unit inverter compressor.
compressor. 3. Refrigerant is leaking or there is under-
charge.
4. Defective EEV.
5. Defective liquid spray valve.
Is the amount of No No
Is there a refrigerant leak or Add or subtract the
refrigerant appropriate for the damaged piping?
system? amount of refrigerant.
Yes
Fix the leak and / or damaged refrigerant

Yes piping and recharge the refrigerant.
Is the discharge tem- No

perature sensor resistance Replace the discharge temperature sensor.
correct?* *Resistance value of discharge temperature sensor:
) Nȍ) Nȍ) Nȍ) Nȍ
Yes
Is the outdoor unit EEV

functioning normally while No
system is in heating mode? See Replace the outdoor unit EEV.
the Troubleshooting Main
Components section.
Yes
Does corresponding No
Check the corresponding
liquid injection operating nor- liquid injection.
mally?
Yes
No Check the other system components

Is the piping (strainer, etc.) and operation conditions.
clogged.
ĺ)L[LIHUURUVDUHIRXQG
Yes
Replace strainer, etc.
112
ERROR CODES
Error No. 34

1. Shutdown due to if compressor high pressure is >4,000 kPa (580
psi) for ten (10) seconds.
2. Defective high pressure sensor.
3. Defective indoor unit and / or outdoor unit fan.
System shut off be- 4. Refrigerant is overcharged.
Outdoor unit cause of an excessive 5. Refrigerant pipe is damaged.
compressor high increase in pressure 6. Defective indoor and / or outdoor unit EEV.
34 pressure safety at the outdoor unit 7. Outdoor unit is blocked during cooling, or indoor unit filter is
tripped. that occurred ten (10) blocked during heating.
consecutive times. 8. Service valve is clogged.
9. Defective outdoor unit PCB.
10. Defective indoor unit pipe temperature.
11. Defective indoor unit pipe temperature sensor.
12. Defective hot gas valve.
No
Is the service valve
Open the service valve.
opened?
Error Codes
Yes
Are the communication No

Check and repair the communication
cable / piping connections
cable / piping connections.
correct?
Yes
No
Is the amount of refrigerant
Adjust the refrigerant amount.
correct?
Yes
Is the fan operating No

correctly? Indoor fan during Replace related parts (Refer to
heating; outdoor fan during Errors No. 105~107).
cooling.
Yes
Is the filter blocked No

Clean indoor filter (heating) / outdoor
(heating: indoor; cooling: out-
heat exchanger (cooling).
door heat exchanger)?
Yes
Is the value of the high No

pressure sensor the same as Replace high pressure sensor.
the manifold value?
Yes
Check indoor unit EEV, indoor unit

PCB, and indoor / outdoor unit
installation.
ERROR CODES
Error No. 35

1. Defective low pressure sensor.
2. Defective indoor unit or outdoor unit fan.
System shut off 3. Refrigerant amount is undercharged or overcharged.
Outdoor unit low because of an 4. Refrigerant piping is damaged.
side pressure excessive decrease
5. Defective indoor / outdoor unit EEV.
35 transducer senses in pressure at the
pressure below outdoor unit that 6. The outdoor unit is blocked (dirty coil) in heating, and/or the indoor
allowable limits. occurred three (3) unit filter is blocked (plugged) in cooling.
consecutive times. 7. Service valve is clogged.
9. Defective indoor unit pipe temperature sensor.
No
Is the service valve
Open the service valve.
opened?
Yes
Are the communication No

Check and repair the communication
cable / piping connections
cable / piping connections.
correct?
Yes
No No
Is the amount of refrigerant Is a piping damaged or
Adjust the refrigerant amount.
correct? refrigerant leak?
Yes Yes
Repair the damaged piping and

recharge refrigerant.
Is the fan operating No

correctly? Outdoor fan during
Check and replace related parts.
heating; indoor fan during
cooling.
Yes
No
Is the strainer unblocked? Replace the strainer.
Yes
Is the value of the low No

pressure sensor the same as Replace low pressure sensor.
the manifold value?
Yes
* If the temperature difference between the inlet and outlet of the strainer is so large that
Check indoor / outdoor unit EEV, frost or ice can be seen, then check for clogs.
indoor unit PCB, and indoor / If ice has not fully formed on the strainer, then the clog is located near the outlet, not at
outdoor unit installation. the inlet.
114
ERROR CODES
Error No. 36

1. Error occurs if the compression ratio is <1.6 (scroll compressor) or
Outdoor unit is <1.8 (rotary compressor) for 2 minutes following a change in position
experiencing a of the reversing valve (either direction), and for 5 minutes following a
problem developing compressor start.
Outdoor unit compressor lift. Er- 2. Pressure differential: <400kPa (scroll compressor), and 500kPa (rotary
36 inverter low com- ror is calling out low compressor).
pression ratio. compression ratio.
System will shut 3. Check bypass between high and low pressure side: EEV fully open,
down and display poor reversing valve operation, direct connection between low
error code “CH36”. and high pressure vapor pipe (especially if reverse connection at
Y-branch.
Error Codes
ERROR CODES
Error No. 40

Disconnection or short circuit of outdoor
Outdoor unit
inverter com- unit inverter compressor current detection 1. Input voltage is not correct.
40 pressor current (CT) sensor. 2. Outdoor unit inverter PCB is damaged (CT
transducer (CT) MICOM input voltage is not within 2.5V sensor component).
sensor error.
±0.3V at initial power up.
No Check if phase voltage is 208-230V ±10%.

Is the input voltage normal? ĺ&KHFNZLUHVDQGFRQQHFWLRQVLISRZHULVQRW
correct.
Yes
No
Is the inverter compressor PCB
Replace inverter compressor PCB assembly.
assembly correct?
Yes
Figure 51: ARUN024 to 053GSS4 Error No .40 Input Voltage Connec- Figure 52: ARUN060GSS4 and ARUB060GSS4 Error No. 40 Input
tions. Voltage Connections.
Measure input voltage. Measure input voltage.
116
ERROR CODES
Error Nos. 41

1. Error can also occur if the system is operating in cooling at
Outdoor unit extremely low temperatures with no low ambient kit.
inverter compres- Disconnection or short circuit 2. Compressor discharge pipe temperature sensor (TH3) is not
of outdoor unit compres- installed or connected properly.
41 sor1 discharge sor discharge temperature
pipe temperature sensor. 3. Defective compressor discharge pipe sensor (TH3) (opened
sensor error. or shorted).
Is the sensor installed No

or connected to the PCB Insert sensor connector to PCB correctly.
correctly?
Yes
No
Is the resistance of
Replace sensor.
the sensor normal?*
Yes
Labels for Outdoor Unit
Sensors: No
Are the sensor resistance
Error Codes
• Outdoor Temperature Sensor: and the temperature values (in Replace corresponding outdoor unit PCB.
TH1 LGMV) the same?
• Pipe Temperature Sensor:
Yes
TH2
• 6WDQGDUGYDOXHVRIVHQVRUUHVLVWDQFHDWGLIIHUHQWWHPSHUDWXUHV
• Discharge Pipe (D-pipe) Replace corresponding sensor. variation): 50°) Nȍ°) Nȍ°) Nȍ°F
Temperature Sensor: TH3 Nȍ
• 2WKHUWHPSHUDWXUHVHQVRUUHVLVWDQFHYDOXHV) Nȍ
) Nȍ) Nȍ) Nȍ
(UURULVJHQHUDWHGLIUHVLVWDQFHLV!0ȍRSHQDQGNȍVKRUW ) Nȍ) Nȍ
Figure 53: ARUN024 to 053GSS4 Error No. 41 Checking the Inverter Figure 54: ARUN060GSS4 and ARUB060GSS4 Error No. 41 Checking
Compressor Discharge Temperature Sensor Resistance. the Inverter Compressor Discharge Temperature Sensor Resistance.
Check the resistance of

the inverter compressor
discharge temperature
sensor.
Check the resistance of

the inverter compressor
discharge temperature
sensor.
ERROR CODES
Error Nos. 42 and 43

Outdoor unit low 1. Check the connection on the outdoor unit
Disconnection or short circuit of outdoor unit
42 pressure sensor PCB.
low pressure sensor.
error. 2. Thermistor shorted or opened.
3. Check for 12 V DC between 12 V and GND
Outdoor unit high (red to black) for 5 V DC.
Disconnection or short circuit of outdoor unit
43 pressure sensor 4. Check the Signal to GND (white to black) and
high pressure sensor.
error. use correct chart from Troubleshooting section
to compare with actual system pressure.
Is the sensor connected No

Connect the sensor to the PCB correctly.
to the PCB correctly?
Yes
No Test for V DC measurements and signal to GND.

Is the sensor operating If sensor measurements fall outside correct
properly? measurements, replace sensor.
Yes
After the outdoor unit main No

PCB is replaced, does the sys- Replace corresponding pressure sensor.
tem operate normally?
Yes
End Images here are representative of system components. Actual compo-

Figure 55: ARUN024 to 053GSS4 Error Nos. 42-43 Checking the Pres- Figure 56: ARUN060GSS4 and ARUB060GSS4 Error Nos. 42-43
sure Sensor Connections. Checking the Pressure Sensor Connections.
Pressure sensor
connection.
Pressure sensor
connection.
118
ERROR CODES
Error Nos. 44, 45, 46

Outdoor unit
ambient air tem- Disconnection or short circuit of outdoor unit
44 perature compressor discharge temperature sensor.
sensor error. 1. Check the connection on the outdoor unit
PCB.
Outdoor unit heat
exchanger pipe Disconnection or short circuit of outdoor unit 2. Thermistor shorted or opened.
45 temperature heat exchanger piping temperature sensor.
sensor error.
1. Check the connection on the outdoor unit

Outdoor unit PCB.
compressor Disconnection or short circuit of outdoor unit 2. Thermistor shorted or opened.
46 suction pipe
temperature compressor suction piping temperature sensor. 3. Check suction sensor in cooling mode;
sensor error. check hot gas sensor located near the heat
exchanger in heating mode.
Error Codes
Are the sensors correctly con- No
nected to the PCB? Check and connect sensor to PCB correctly.
Yes
Is the value of the No

temperature sensor normal? Replace sensor.
Yes
Replace outdoor unit PCB.

ERROR CODES
Error No. 50

1. Input voltage is not correct. Power wiring con-
nections could not be correct.
Outdoor unit loss Input power line connection(s) is / are
50 2. Noise filter and / or connection error.
of phase. missing for the outdoor unit.
3. Main PCB could be damaged.
4. Inverter PCB input current sensor error.
Are the power wiring connec- No Check wiring connections.

tions correct? ĺ5HZLUHLIHUURUVDUHIRXQG
Yes
No Check if phase voltage is 208-230V ±10%.

Is the input voltage normal? ĺ&KHFNZLULQJIRUGDPDJHDQGFRQQHFWLRQVLI
power is not correct.
Yes
1. Check if phase voltage is 208-230V ±10%.

No
Is the main PCB 2. Check main PCB assembly; check wiring for
assembly correct? disconnections and damage.
Yes
Is the noise filter No

operating properly and / or Rewire and / or replace if errors are found.
Yes
No
Inverter PCB LED display
Replace Inverter PCB assembly.
error.
Yes
120
ERROR CODES
Error No. 51

1. Total indoor unit capacity is more than
130% outdoor unit rated capacity.
Combination ratio Value of total indoor unit capacity exceeds
51 2. Wrong communication cable / piping
is out of range. allowable outdoor unit capacity specifications.
connections..
Is the total capacity Is the total capacity of Check communication

indoor units <130% of the No indoor units <130% of the No
cables between indoor
outdoor unit capacity on the outdoor unit capacity on the and outdoor units
LGMV report? LGMV report?
Yes Yes
End. Adjust the capacity of the

indoor and outdoor units.
Error Codes
ERROR CODES
Error No. 52

Communication
error between 1. Power wiring or communication cable is
Outdoor unit main controller (PCB) cannot
outdoor unit in- disconnected.
52 receive signal from inverter compressor con-
verter compressor 2. Defective outdoor unit inverter compressor
WUROOHU3&%>V@
PCB(s) and main PCB.
PCB.
Is the yellow commu- No Reconnect communication

nication LED for the inverter
cable.
compressor PCB on?
Yes
Is the communication cable No Reconnect communication

connected properly? cable.
Yes
No
Is the main PCB functioning Replace Main PCB.
normally?
Yes
Replace the inverter compressor PCB.
Checking the Main PCB and Inverter PCB (If Normal, Communication LED Blinks).
Figure 57: ARUN024 to 053GSS4 Error No. 52 Checking the Inverter Figure 58: ARUN060GSS4 and ARUB060GSS4 Error No. 52 Checking
Compressor Connections. the Inverter Compressor Connections.
Inverter Communication LED Inverter Communication Connection
Inverter
Communication
Inverter LED
Communication
Connection

122
ERROR CODES
Error No. 53

1. Communication cables are not connected
between external PCB and indoor PCB.
2. Communications cables are disconnected
or have short circuited between the main
PCB and external PCB.
Communication 3. Communication cables are disconnected or
error between have short circuited between the main PCB
Outdoor unit main PCB cannot receive the
53 outdoor unit main
signal from the indoor unit. and communication PCB.
PCB and indoor
unit(s) PCB. 4. Communication cables are disconnected or
have short circuited (communication cable
connection error.)
5. Power to the indoor PCB is off.
6. Defective outdoor unit main PCB, communi-
cation PCB, and / or indoor unit PCB.
Is the power supplied to the No
Error Codes
Supply power.
indoor unit PCB?
Yes 1. Check the communication cable between outdoor unit external

PCB and indoor unit PCB. Reconnect communication cable.
2. Check communication cable between cycle and outdoor unit
Is the communication cable No external PCB. Reconnect communication cable.
connected correctly? 3. Check communication cable between cycle and communication
PCB. Reconnect communication cable
4. Check if communication cable connections are properly
installed. If not, replace communication cable.
Yes 1. Is the quantity of indoor units connected correct after the auto
addressing procedure is performed? Check communication
PCB.
Is the quantity of indoor No
units connected the same as 2. Check if the communication PCB LED is blinking. If not, replace
what is displayed in LGMV? communication PCB.
3. If the error is not fixed after the communication PCB is replaced
Yes and the auto addressing procedure is performed, check the
outdoor unit main PCB.
Check communication cable and installation.
ERROR CODES
Error No. 53 indicates there is a communication error between the outdoor unit and indoor unit(s). See LGMV to help determine which indoor
unit or units are not communicating with the outdoor unit.
• Does LGMV display the correct number of indoor units? If LGMV DOES NOT display the correct number of indoor units, find the missing
indoor unit or units and troubleshoot.
• If LGMV DOES displays the correct number of indoor units, but the outdoor unit still shows CH53, check the communication count line on
LGMV. Find the indoor unit that does not have a communication count increase—that indicates the indoor unit which is not communicating.
The indoor unit can have:
1. Wrong communication cable or power wiring connection(s).
2. A PCB malfunction.
3. Duplicate address numbers for indoor units (Error No. 53 will appear at the indoor unit).
• If communication in general is not functioning properly, then the

auto addressing procedure has not been performed yet or has not
been performed properly.
• Auto addressing must be performed after an indoor unit PCB has
been replaced. Also, if a central controller is installed, the central
controller address must be input.
• In addition to the information presented here, see also trouble-
shooting procedure for Error No. 05.
Figure 59: ARUN024 to 053GSS4 Error No. 53 Checking the PCB Figure 60: ARUN060GSS4 and ARUB060GSS4 Error No. 53 Checking
Connections. the PCB Connections.
Communication Connections on Main PCB Indoor Unit
Communication Connections on Main PCB
Communication PCB
Indoor Unit
Communication PCB
IDU A/IDU B
Example of Wiring Damage Remark : IDU A/IDU B
Example of Wiring Damage
124
ERROR CODES
Error No. 57

1. Bad connection between main and inverter
Communication PCBs.
error between
Outdoor unit inverter PCB is not receiving 2. Communication wire noise effect.
57 outdoor unit main
signal from main PCB. 3. The outdoor unit main PCB is damaged.
PCB and inverter
PCB. 4. The outdoor unit inverter PCB is
damaged.
Are the communi- No 1. Check communication wiring.

cation cable connections 2. Check connections.
correct? ĺ5HZLUHLIHUURUVDUHIRXQG
Yes
Is the inverter PCB No

Replace Inverter PCB.
assembly correct?
Yes
Error Codes
After resetting the No
power, does the error still Replace main PCB.
display?
Yes
Main PCB Inverter PCB
Main PCB
Inverter PCB
ERROR CODES
Error No. 60

1. EEPROM contact is defective, or the con-
Outdoor unit tact is not inserted correctly.
inverter PCB
60 EEPROM access and "Check SUM" errors. 2. Different EEPROM version.
EEPROM
error. 3. Outdoor unit inverter PCB assembly is
damaged.
No 1. Check EEPROM insertion / connection.

Is EEPROM insertion correct?
2. Check EEPROM; check SUM.
ĺ5HSODFHLIHUURUVDUHIRXQG
Yes
Is the inverter PCB assembly No

correct? Replace inverter PCB assembly.
Yes
Replace EEPROM only after the power is turned off. There is a risk of Images here are representative of system components. Actual compo-
electric shock that could cause physical injury or death. nent appearance depends on model and system type.
Inverter EEPROM Connection. Inverter EEPROM Connection.
Correct Inverter EEPROM Installation Direction. Correct Inverter EEPROM Installation Direction.
126
ERROR CODES
Error No. 62

1. Inverter PCB IPM connection is not
correct.
2. Outdoor unit fan motor operation is
High temperature
malfunctioning.
at the outdoor unit
62 Heat sink temperature is >257°F. 3. Outdoor unit inverter PCB assembly is
inverter PCB heat
defective.
sink.
4. Overload operation (pipe is clogged, fan is
blocked, EEV is defective, overcharge in
refrigerant).
No 1. Check piping for clogs or damage.

Is the installation correct?
2. Check if the outdoor unit or indoor unit air flow is blocked.
3. Check EEV connections / assembly / or if the EEV is operating normally.
Yes
4. Check refrigerant pressure
5. Check power wiring to see if it is connected properly or is damaged.
ĺ5HDVVHPEOHRUVHUYLFHLIHUURUVDUHIRXQG
Error Codes
Is the inverter PCB IPM con- No
Check inverter PCB connections.
nection correct?
ĺ5HFRQQHFWLIHUURUVDUHIRXQG
Yes
Is the outdoor unit No
Check the outdoor unit fan motor operation and / or if it is locked up.
fan motor operating
ĺ5HDVVHPEOHRUVHUYLFHLIHUURUVDUHIRXQG
normally?
Yes
No
Is the inverter PCB
Replace inverter PCB assembly.
assembly correct?
Yes
Figure 66: ARUN060GSS4 and ARUB060GSS4 Error No. 62 Checking
Recheck power and installation. the Connections (JIS Screwdriver Required).
Check Connections.
Checking the Inverter PC Connections.
Figure 65: ARUN024 to 053GSS4 Error No. 62 Checking the Connec-
tions (JIS Screwdriver Required).
Check Connections.
Always apply heat transfer

paste to the new inverter PCB
heat sink before installing. For
instructions, see “Replacing the
Inverter PCB Heat Sink” page
later in this section.
ERROR CODES
Error No. 65

1. Defective temperature sensor connection.
Outdoor unit liquid
pipe (condens- 2. Defective temperature sensor (sensor has
65 er) temperature Abnormal sensor resistance value.
(opened or shorted).
sensor error.
Are the temperature sensor No

connections correct? Check and connect sensor to PCB.
Yes
Is the value of the No

temperature sensor resistance Replace sensor.
normal?
Yes

See also Error Code No. 113, Outdoor Unit Liquid Pipe (Condenser) Temperature Sensor Error.
128
ERROR CODES
Error No. 67

1. Fan motor is defective or assembly is not
correct.
2. Fan motor connection is wrong (U,V,W
530LV530IRUILYHVHFRQGVZKHQWKH output).
Outdoor unit fan
67 RXWGRRUXQLWIDQVWDUWVRU530DIWHUIDQ
has locked up. 3. Rotation has reversed after RPM target is
starts.
achieved.
4. Fan PCB assembly is defective.
5. Fan air flow is blocked by heavy snowfall.
Is the outdoor unit fan mo- No Check outdoor unit fan motor assembly.
tor assembly correct? ĺ5HDVVHPEOHRUUHSODFHLIHUURUVDUHIRXQG
Yes
1. Check resistance between each phase (U,V,W) of the out-
GRRUXQLWIDQPRWRUWHUPLQDOȍDW
Is the outdoor unit fan motor No
2. Check insulation resistance between the outdoor unit fan
operating normally?
motor terminals (U,V,W).
Error Codes
Yes ĺ5HDVVHPEOHRUUHSODFHLIHUURUVDUHIRXQG
Are the outdoor unit No Check wiring between outdoor unit fan motor and fan PCB.
fan motor wiring connections Check if the motor output terminal colors match.
Yes
No
Is the fan PCB assembly
Replace fan PCB assembly.
correct?
Yes

If the outdoor unit is covered in thick snow, remove before operating system.
Connections. the PCB Connections. Inverter PCB
Inverter PCB
Fan 1
Fan 1
Fan 2
Fan 2
ERROR CODES
Error No. 86

Outdoor unit main
1. No EEPROM.
86 PCB onboard EEPROM access error.
2. EEPROM is not inserted properly.
EEPROM error.
Is the EEPROM No
Reset after checking the EEPROM assembly.
assembled correctly?
Yes
No
Is the check sum correct? Replace with correct EEPROM.
Yes
Replace EEPROM only after the power is turned off. There is a risk of
Recheck power and installation. electric shock that could cause physical injury or death.
Figure 69: ARUN024 to 053GSS4 Error No. 87 Checking the EEPROM. Figure 70: ARUN060GSS4 and ARUB060GSS4 Error No. 87 Checking
the EEPROM.
Inserting the EEPROM.
Inserting the EEPROM.
EEPROM
EEPROM
Main PCB
Correct Inverter EEPROM

Installation Direction (Same
direction for both the socket
and EEPROM holes).
Main PCB
Correct Inverter EEPROM
Installation Direction (Same
direction for both the socket
and EEPROM holes).
130
ERROR CODES
Error Nos. 113 and 115

Outdoor unit liquid
Disconnection or short of outdoor unit liq-
pipe (condenser)
113 uid pipe (condenser) temperature sensor
temperature
(sensor value is abnormal). 1. Defective temperature sensor connection.
sensor error.
2. Temperature sensor has opened or shorted.
Outdoor unit
Disconnection or short circuit of outdoor 3. Defective outdoor unit PCB.
subcooling outlet
115 unit subcooling outlet temperature sensor
temperature
(sensor value is abnormal).
sensor error.
Are the temperature sensor No Check and fix the connections.

Yes
No
Is the temperature sensor
Replace sensor.
resistance value normal?
Error Codes
Yes

See also Error Code No. 65: Outdoor Unit Liquid Pipe (Condenser) Temperature Sensor Error.
ERROR CODES
Error No. 1501

After at least 10 minutes of
Code indicates that based on current superheat measurements, compressor operation, the master
there is a high possibility of liquid refrigerant flooding back and outdoor unit microprocessor will
damaging the compressor.
calculate the system’s compressor
'LVFKDUJHVXSHUKHDWLV)OLTXLGE\SDVVIRUPLQXWHV superheat. If at any time during
Code can only occur when the outdoor is operating in cooling mode compressor operation where all
Outdoor unit (all indoor units must be in cooling mode; error cannot occur during indoor units in thermal on are in
compressor simultaneous operation). cooling mode and the compressor
discharge The first time superheat falls below <4.8°F (<3ºC) for 5 minutes, the superheat falls <4.8°F (<3ºC) for
superheat not system will shut down and CH1501 is displayed on all indoor unit PLQXWHVWKHUHLVDKLJKSURED-
1501 bility that liquid could flood back to
satisfied. zone sensors and central control devices. After the initial occur-
(ARUN / rence, the outdoor unit cycles off and will auto-restart. the inlet of the compressor scroll,
ARUB60GSS4 Following the initial restart, and after 10 minutes of operation to al- resulting in compressor damage.
only) low the system time to stabilize, if the superheat again falls <4.8°F 1. Indoor unit EEV has disconnect-
(<3ºC) for 5 minutes, the system will shut down and auto restart for ed or short circuited.
a second time. 2. Defective compressor EEV
If error occurs 3 times within any 1 hour period of compressor oper- (large refrigerant leak has
ation, the error code will be assigned a Level 3, and the system will occurred).
shut down and remain off. A manual restart will be necessary. 3. Defective liquid piping and / or
vapor piping connections.
Is there an indoor unit No Is the SC EEV or No Check liquid and vapor piping
that is leaking a large amount of connections.
refrigerant?* the SC circuit leaking??
Yes Yes
Replace the SC EEV or

SC EEV assembly.
No
Is the EEV coil assembly Re-assemble or replace the
correct? EEV coil.
Yes
No
Are the EEV connections
Connect EEV connections.
correct?
Yes
Replace EEV assembly.
*Excessive refrigerant leak: Both the piping inlet and outlet temperatures are <50°F when the indoor unit is off (EEV 40 pulses). Also, a loud
refrigerant flow noise was heard.
132
ERROR CODES
Error No. 151

1. Problem with four-way valve operation
because of sludge, inflow, etc.
The difference 2. No pressure difference because of
Not enough pressure difference between high
between the high compressor error.
151 and low. Function error of outdoor unit four-
and low pressure 3. Incorrect installation of outdoor unit to indoor
way reversing valve.
is too low. unit piping.
4. Defective four-way valve (resistance is not
ȍ
Is the four-way valve con- No

nected properly? Reconnect the four-way valve.
Yes
Is the four-way No
valve coil resistance normal Change the four-way valve coil.
ȍ"
Error Codes
Yes
Is the four-way valve No

coil connected to the four-way Re-insert four-way valve coil.
valve correctly?
Yes
After power is reset

No
and heating mode begins,
can supply voltage be verified
at the PCB?
Yes
After the mode is

change from cooling to No
heating or vice versa, does the Replace the four-way valve.
same error occur again?
Yes
Is the compressor operat- No

Check and replace compressor (magnet switch,
ing normally? corresponding PCB, see electric components).
Yes
Replace 4 way valve.
To get the valve to switch, close the outdoor unit hot gas service valve,
then put the system in heat mode, and if pressure builds, slowly open
the hot gas valve.
ERROR CODES
Location of the four-way valve connector on

the Main PCB (marked as “4way, CN09”).
Measure the four-way valve resistance. ARUN24~53GSS4 Main PCB ARUN / ARUB60GSS4 Main PCB
Check the output voltage of the terminal socket

Confirm the four-way valve coil is completely inserted. during heating operation (output must be 230 V AC).
134
ERROR CODES
Error No. 51 C

After auto-pipe detection is complete, wait 5 minutes, then
verify connected capacity. System will display error if:
• The heat recovery unit port addresses are all unique,
then >54 Mbh single indoor unit connected; >54 Mbh total
of multiple indoor units connected.
• If 2 heat recovery unit port addresses are the same and
Total capacity of indoor unit(s) the ports are twinned; >108 Mbh total of multiple indoor
Capacity of indoor connected to each heat recovery units are connected.
51 C+ No. (#) of units connected to unit port exceeds allowable limits. • If 3 heat recovery unit port addresses are the same and
the heat recovery
Heat Recovery Unit unit exceeds Error code displays on the outdoor the ports are all connected, >162 Mbh total of multiple
allowable limits. unit SSD, the heat recovery unit indoor units connected.
SSD, or in LGMV. • If the total connected indoor unit nominal capacity ex-
ceeds 192 Mbh for a single heat recovery unit.
1. Communication cable or piping is not connected prop-
erly.
2. Heat recovery PCB DIP switch is not set correctly.
3. The indoor unit connected on the heat recovery unit port
Error Codes
exceeds the allowable capacity limit.
Error Code 51 C+ No. (#) of Heat Recovery Unit is displayed differently depending on which device it is viewed from:
1. If viewed from the master outdoor units SSD: The display shows “51c” where “c” is the heat recovery unit count number of the overcon-
nected device assigned by auto-pipe detect.
2. If viewed from the heat recovery unit PCB board display that is overconnected: The display will show “CH51”.
3. If viewed from an heat recovery unit that is not overconnected: The display will show nothing.
4. If viewed from any indoor unit zone controller: Nothing will be displayed.
5. If viewed from LGMV maintenance software on a PC: The screen will show CH51h where “h” is the heat exchanger address of the over-
connected heat recovery unit.
1. Check if the communication cable and piping between the heat recovery unit(s) and the indoor unit(s) installed correctly.
2. Check if the DIP switches are set correctly for each connection condition between the heat recovery unit(s) and the indoor unit(s)
3. ,IWKHLQGRRUXQLWFRQQHFWHGWRWKHKHDWUHFRYHU\XQLW,6LQDJURXSFRQWURODSSOLFDWLRQFKHFNLIWKHFRUUHVSRQGLQJFDSDFLW\LVN%WX
4. ,IWKHLQGRRUXQLWFRQQHFWHGWRWKHKHDWUHFRYHU\XQLW,6127LQDJURXSFRQWURODSSOLFDWLRQFKHFNLIWKHFRUUHVSRQGLQJFDSDFLW\LV
kBtu (including zoning control).
5. If the error occurs again even after following Steps 1 through 4 above, replace the corresponding heat recovery unit PCB.
6. When Steps 1 through 4 (or Steps 1 through 5 if the heat recovery unit PCB needs to be replaced) are completed successfully, perform
the auto addressing and piping detection procedures.
ERROR CODES
Error No. 2001

1. Power wiring or the communications cable
to the heat recovery unit is defective.
2. After auto addressing, indoor unit has the
After auto operation, the number of the indoor
Auto pipe search wrong address (defective indoor unit PCB
units detected is different from the number of
2001 failure. and / or power wiring / communications
communicating indoor units.
cable).
3. Heat recovery unit rotary or DIP switch
setting(s) is (are) wrong.
4. Heat recovery unit PCB is defective.
1. See if the green communication LED of the heat recovery unit is blinking.
2. If the green communication LED of the heat recovery unit is consistently blinking:
• Check the input power of the heat recovery unit.
• 5HVHWSRZHUWRWKHRXWGRRUXQLWDQGKHDWUHFRYHU\XQLWZDLWIRUWKLUW\PLQXWHVVRWKHSLSLQJWHPSHUDWXUHZLOOFRROGRZQDQGWKHQ
perform the auto addressing procedure.
• While the power to the heat recovery unit is on, check if error code “CH05” is displayed (see troubleshooting instructions for Error No.
CH05).
3. If the green communication LED of the heat recovery unit is still consistently blinking, check the rotary switch and DIP switch settings.
5HVHWSRZHUWRWKHRXWGRRUXQLWDQGKHDWUHFRYHU\XQLWZDLWIRUWKLUW\PLQXWHVVRWKHSLSLQJWHPSHUDWXUHZLOOFRROGRZQDQGWKHQ
perform the auto addressing procedure.
4. If the number of indoor units is different than what is actually installed and what number is displayed after the auto addressing procedure
LVILQLVKHGFKHFNWKHSLSLQJLQVWDOODWLRQ2XWGRRUXQLWļ+HDW5HFRYHU\XQLWļ,QGRRUXQLW
5. If an indoor unit has not been connected to the first port (No. 1 Valve) of the heat recovery unit, set the heat recovery unit piping
manually.
136
ERROR CODES
Error Nos. 201C, 202C, 203C

Heat recovery unit
201 C+ No. (#) of liquid piping tem-
Heat Recovery Unit perature sensor
error.
Heat recovery unit 1. Defective temperature sensor connection.
202 C+ No. (#) of subcooling inlet
Abnormal sensor value (sensor has 2. Defective temperature sensor (sensor has
Heat Recovery Unit piping tempera-
disconnected or has shorted out). disconnected or has shorted out).
ture sensor error.
Heat recovery
unit subcooling
203 C +No. (#) of
discharge piping
Heat Recovery Unit
temperature
sensor error.
1. Check the connections of the temperature sensor and the lead cable.
2. ,VWKHYDOXHRIWHPSHUDWXUHVHQVRUQRUPDO",IQRWUHSODFHVHQVRUSLSLQJWHPSHUDWXUHVHQVRU) Nȍ) Nȍ
) Nȍ
Error Codes
3. If the sensor connection and values are correct, replace the outdoor unit PCB.
Heat Recovery HR HR HR HR HR HR HR HR HR HR HR HR HR HR HR HR
Unit No. 1 No. 2 No. 3 No. 4 No. 5 No. 6 No. 7 No. 8 No. 9 No. 10 No. 11 No. 12 No. 13 No. 14 No. 15 No. 16
Error C01 C02 C03 C04 C05 C06 C07 C08 C09 C10 C11 C12 C13 C14 C15 C16
Displayed
Example of Heat Recovery R unit Error

• +HDW5HFRYHU\8QLW6XEFRROLQJ,QOHW3LSLQJ7HPSHUDWXUH6HQVRU(UURUĺ&5HSHDWHG
• C = Heat Recovery Unit
• # = Heat Recovery Unit Number
ERROR CODES
Error No. 204 C

1. Heat recovery unit power wiring and / or communi-
cation cable connections are defective.
Communication
2. Heat recovery unit rotary or DIP switch setting(s) is
204 C+ No. (#) of error between out- Outdoor unit does not receive signal
(are) wrong.
Heat Recovery Unit door unit and heat from heat recovery unit.
3. Defective heat recovery unit communications PCB
recovery unit.
(sub PCB).
4. Defective heat recovery unit main PCB.
1. Check power wiring and communication cable connections. Check if the green communication LED on the heat recovery unit PCB is
blinking.
2. If the green communication LED is blinking normally, check the rotary and DIP switch settings on the heat recovery unit (See Error No.
200). Reset the power to the outdoor and heat recovery units. (If there is a heat recovery unit communication error, it can’t be released
until the power to the outdoor unit is reset.)
3. If the green communication LED of the heat recovery unit PCB is not blinking (on continuously), check if the communication of the total
indoor units is normal (See Error No. 05). If the green communication LED of the heat recovery unit PCB is not blinking (on continuously),
and even if communication to the indoor unit is functioning, replace the heat recovery unit PCB.
DANGER
• High voltage electricity is required to operate this system. Adhere to the NEC code and these instructions when wiring. Improper connec-
tions and inadequate grounding can cause accidental injury or death.
• Turn the power off before servicing the equipment. Electrical shock can cause physical injury or death.
• Do not operate the disconnect switch with wet hands. There is risk of fire, electric shock, physical injury or death.
• Disconnects must only be performed by a properly licensed electrician. Incorrect wiring could cause the disconnect to explode, leading to
• Do not operate the unit with the panel(s) or protective cover(s) removed. The hot, cold, and high-voltage parts of the unit can cause
• Do not touch the refrigerant piping during or after operation. It can cause burns or frostbite.
• If the power wiring and communication cables on the heat recovery unit(s) and indoor unit(s) are not properly connected (connections
switched), the communication components will burn out.
• Do not supply power to the unit until all electrical wiring and controls wiring are completed.
Heat Recovery Unit PCB

No. 4 Valve Housing
Images here are representative of system components.
Actual component appearance depends on model and
No. 1 Valve Housing
system type.
SSD
SW05M
SW01M
SW02M
SW01M / SW03M / SW04M
DIP switch for setting up
Switches for manual valve
Heat Recovery Unit functions.
addressing.
SW03M SW04M
138
ERROR CODES
Error No. 205 C

1. Communication problem occurred between
the heat recovery unit PCB and the connec-
Communication error occurred between the tion to the communications bus (the heat
heat recovery unit and the 485 modem (2A
Communication Series Heat Recovery Units). recovery unit 485 modem).
error between 2. Error displays if the outdoor unit signal is
heat recovery The 2A Series heat recovery unit applies only
205 C+ No. (#) of not received for three (3) minutes. The error
unit and the 485 to heat recovery systems communicating at a
Heat Recovery Unit modem (2A Series baud rate of 9,600 bps. clears after the signal is received from the
Heat Recovery modem. (2A Series Heat Recovery Units.)
The 485 modem is the communications style on
Units). 3. Incorrect wiring between the heat recovery
the bus that is 1e outdoor unit to many indoor
unit and the 485 modem.
units.
4. The 485 PCB modem is defective.
5. The heat recovery unit PCB is defective.
1. Check the communication cable connection between the heat recovery unit (2A Series) and the 485 modem. Check if the red LED is on.
2. If the red LED on the 485 modem is on, reset the outdoor unit and the power of the heat recovery unit.
3. If the red LED on the 485 modem is flashing, replace the 485 modem.
4. If the red LED on the 485 modem still flashes even after it is replaced, replace the heat recovery unit PCB.
Error Codes
ERROR CODES
Error No. 206 C

1. A heat recovery unit address is duplicated
for 485 communication.
The heat recovery unit address is duplicated for 2. There are two heat recovery units with
485 communication (2A Series Heat Recovery one or more HEX addresses that are the
Units). same.
Duplicate address • The 2A Series heat recovery unit applies only
3. Adjust the HEX address dial found on the
206 C+ No. (#) of error of the heat to heat recovery systems communicating at a heat recovery units (error of the rotary
Heat Recovery Unit recovery unit (2A baud rate of 9,600 bps. switch address settings on the heat recov-
Series).
• The 485 modem is the communications style on ery unit).
the bus that is 1e outdoor unit to many indoor 4. The power wiring and / or the communica-
units. tion cable connection of the heat recovery
unit is defective.
5. The heat recovery unit PCB is defective.
1. Check if the rotary switch settings on each heat recovery unit PCB are set correctly. If not, set the rotary switches again, verifying that the
settings are different on the different heat recovery units.
2. Reset the outdoor unit and the power of the heat recovery unit so that the updated rotary switch settings are applied / saved to the sys-
tem.
3. After Step No. 2 is complete, perform auto addressing again.
4. If the error occurs again even after auto addressing is complete, replace the corresponding heat recovery PCB.
• Error Code 206C only occurs on heat recovery units with a 485 modem (2A Series heat recovery units; 9,600 bps communication).
• Refer to the outdoor unit installation manual for heat recovery unit rotary switch address settings.
485 Modem on 2A Series Heat Recovery Units

140
ERROR CODES
Error No. 237

Communication 1. Check if the outdoor unit has been powered
Indoor unit communications PCB is not receiv- and if auto addressing has occurred.
error between
ing signal from outdoor unit communications
237 outdoor unit PCB 2. Check communication cable.
PCB for more than 3 minutes. Check RS-485
and indoor unit 3. Check outdoor unit communication mod-
communications for issues.
PCB. ule.
No
Is the outdoor unit powered? Turn on power to the outdoor unit.
Yes
Has the auto address- No Perform the auto addressing procedure.

ing procedure been per- Verify that it was successful with no errors.
formed?
Yes
Error Codes
1. Check the communication cable between
Is the communication cable No outdoor unit and indoor unit. Reconnect
connected correctly? communication cable.
2. Check if communication cable / con-
nections are properly installed and / or
damaged. Replace communication cable
/ connections if necessary.
Is the outdoor unit No Check if outdoor unit communication

communication module oper- module installation and connections are
ating properly? correct; if not reconnect and / or reinstall.
See also Error Code No. 05: Indoor Unit PCB Communication Error between Outdoor Unit and Indoor Unit, and Error Code No. 238: Outdoor Unit
PCB Communication Error Between Indoor Unit and Outdoor Unit.
ERROR CODES
Error No. 238

Communication 1. Check if the outdoor unit has been powered
Indoor unit communications PCB is not receiv-
error between and if auto addressing has occurred.
ing signal from outdoor unit communications
238 outdoor unit PCB
PCB for more than 3 minutes. Check outdoor 2. Check communication cable.
and indoor unit
unit PCB communications for issues. 3. Check outdoor unit PCB.
PCB.
No
Is the outdoor unit powered? Turn on power to the outdoor unit.
Yes
Has the auto address- No Perform the auto addressing procedure.

ing procedure been per- Verify that it was successful with no errors.
formed?
Yes
1. Check the communication cable between

Is the communication cable No outdoor unit and indoor unit. Reconnect
connected correctly? communication cable.
2. Check if communication cable / con-
nections are properly installed and / or
damaged. Replace communication cable
/ connections if necessary.
Is the outdoor unit No Check if outdoor unit communication

communication PCB operat- PCB installation and connections are
ing properly? correct; if not reconnect and / or reinstall.
See also Error Code No. 05: Indoor Unit PCB Communication Error between Outdoor Unit and Indoor Unit, and Error Code No. 237: RS-485 Com-
munication Error Between Indoor Unit and Outdoor Unit.
142
ERROR CODES
Error No. 242

1. RS-485 communication wiring defect.
2. Communication defect between remote
controller and indoor unit.
242 Network error. Network error of central controller.
3. RS-485 DIP switch setting error
4. Indoor unit addressing setting error on
central controller
Is the communications No
cable of the RS-485 properly Reconnect RS-485 communications cable.
connected.
Yes
No
Are any indoor unit Reset any indoor unit addresses that are
addresses repeated? repeated.
Error Codes
Yes
No
Is the simple central con- Set the slave mode with the simple central
troller setting correct? controller after the system is reset.
Yes
Communications LED Between the Network and the Outdoor Unit

(The communications LED flashes on and off when communica-
tion is normal between the network and the outdoor unit.)
Incorrect RS-485 Communication Wiring
REPLACING THE INVERTER
PCB HEAT SINK
Replacing the Inverter PCB Heat Sink

If the inverter PCB is replaced at any time, the heat sink must be replaced.
,IWKHUHLVQ¶WDQ\KHDWVLQNSDVWHRULVQ¶WDVXI¿FLHQWDPRXQWRIKHDWVLQNSDVWHEHWZHHQWKHLQYHUWHU3&%DQGWKHRXWGRRUXQLWKHDWVLQNSODWHWKH
XQLWZLOORYHUKHDWFDXVLQJD¿UHSK\VLFDOLQMXU\RUGHDWK
,IWKHUHLVQ¶WDQ\KHDWVLQNSDVWHRULVQ¶WDVXI¿FLHQWDPRXQWRIKHDWVLQNSDVWHEHWZHHQWKHLQYHUWHU3&%DQGWKHRXWGRRUXQLWKHDWVLQNSODWHWKH
unit will overheat and damage the PCB and outdoor unit.
1. Remove inverter PCB by detaching its screws using a JIS screwdriver.
Only use a JIS screwdriver. A standard Phillips screwdriver will damage / strip the inverter PCB screw heads.
2. Wipe off any existing heat sink paste material from the inverter PCB heat sink plate, as well as from the outdoor unit heat sink plate.
Gently scrape off as much heat sink paste material as possible, taking care not to damage the back of the inverter PCB or the outdoor unit
heat sink plate.
3. Evenly apply a coating of silicone-based electronic heat sink paste to the inverter PCB heat plate. Verify all applicable areas of the PCB
heat plate are completely covered. Do not let foreign matter settle onto the heat sink paste.
4. Reinstall the inverter PCB by reattaching its screws a JIS screwdriver. Tighten the screws, but do not overtighten.
144
CHECKING THE PHASE DIODE BRIDGE
Checking the Inverter Compressor Phase Diode Bridge

1. Shut off main power. After main power is shut off, wait at least ten (10) minutes until Figure 71: 6LPSOL¿HG'LDJUDPRID3KDVH'LRGH
inverter compressor PCB DC voltage is discharged. Bridge.
R S T
After switching off the main power supply and verifying that the DC voltage was discharged, wait
for at least ten (10) minutes before checking the electrical components in the control box. There
is risk of electric shock, physical injury or death.
2. Disconnect all connections to the phase diode bridge.
3. Set the multi-tester to diode mode.
4. Measured value must be 0.4V ~ 0.7V as shown in table below.
5. If the measured value is different than what is listed in the table below, set the multi-
WHVWHUWRUHVLVWDQFHPRGHDQGPHDVXUHDJDLQ,IWKHYDOXHLVWRRORZȍRUWRRKLJK
KXQGUHGV0ȍWKHLQYHUWHU3&%QHHGVWREHUHSODFHG
Error Codes
6. If the diode bridge is damaged, check if the inverter PCB assembly
(IPM) also needs to be replaced.
Table 62: Checking the Phase Diode Bridge.

Diode Terminal + Terminal: - Terminal:
Tester Terminal black (-) red (+)
R (~) : Red (+) 0.4V ~ 0.7V -
S (~) : Red (+) 0.4V ~ 0.7V -
T (~) : Red (+) 0.4V ~ 0.7V -
R (~) : Black (-) - 0.4V ~ 0.7V
S (~) : Black (-) - 0.4V ~ 0.7V
T (~) : Black (-) - 0.4V ~ 0.7V
Red (+) and Black (-) are the multi-tester terminals.
CHECKING INPUT VOLTAGE IN CASE
OF POWER ON
&KHFNLQJ,QSXW9ROWDJH2QH3KDVH7ZR:LUH Figure 73: Multi-Meter (Note the

Figure 72: Checking Converter DC Link Voltage. Probe Color).
Main 12V
Red
Inv. Inv. Inv.
GND 5V 15V
Main.
GND
Black
Main
2 Wire
Inverter
Power 310V
GND Noise Filter
L N on model and system type.
Table 63: Input Voltage Measurements.

Multi-Meter Measured Value
Check Mode
Black Red Normal Abnormal
Input Voltage (1-Phase / 2-Wire 220V) AC N L 220V ± 15% Not Normal
Inv. 5V 5V 4.5V ~ 5.5V 9Ļ
Inv. GND
Inv. 15V 15V 14.5V ~ 15.5V 9Ļ
DC Voltage Main 5V DC 5V 4.5V ~ 5.5V 9Ļ
Main GND
Main 12V 12V 11.5V ~ 12.5V 9Ļ
310V Power GND 310V 310V ± 20% 9Ļ9Ĺ
146
CHECKING ODU TO ODU
COMM. (DC VOLTAGE) IN CASE OF POWER ON
Figure 74: Checking ODU to ODU Communications (DC Voltage). Figure 75: Multi-Meter (Note the
Probe Color).
Comm. Connector
(White) Red
2 1
5V
4 3
(pin1)
GND3 6 5
12V
8 7
(pin2) (pin7) Black
10 9
12 11
14 13
16 15
18 17
20 19
22 21
24 23
24 23
Error Codes
26 25
28 27
Table 64: ODU to ODU Communications (DC Voltage) Measurements.

Check Mode
Main (DC-Comm.) DC GND3 (pin2) 5V (pin1) 4.5V~5.5V 9Ļ
CHECKING INVERTER PCB IN CASE
OF POWER OFF
Figure 76: Checking Inverter PCB. Figure 77: Multi-Meter (Note the
Probe Color).
Main
12V
Inv. Main
Inv. Inv. Red
GND 5V
5V 15V
Main.
Fuse GND
Black
Fuse
Main
Fuse
IPM Fuse
GND
U V W P on model and system type.
Table 65: Inverter PCB Measurements.

Check Mode
Fuse Both sides Short Open
5V part
ȍ Main / Inv. GND Main / Inv. 5V NȍĹ NȍĻaȍ
Resistance
15V part
ȍ Main / Inv. GND Main / Inv. 15V ȍĹ ȍĻaȍ
Resistance
U
P V
W 0.35V ~ 0.7 V
IPM Not Normal
U
V IPM GND
W
148
OF POWER OFF
Probe Color).
Red
Bridge Diode Black
B/D L N B/D(+)
GND
Error Codes
FRD2
IGBT1, IGBT2 FRD1

Check Mode
Fuse Both sides Short Open
5V part
ȍ Main / Inv. GND Main / Inv. 5V NĹ NĻa
Resistance
15V part
ȍ Main / Inv. GND Main / Inv. 15V Ĺ Ļa
Resistance
B/D (+) L
Bridge Diode L N
N B/D GND 0.35V ~ 0.7V Not Normal
FRD - +
IGBT - +
OF POWER OFF
Probe Color).
Red
Black
Reactor
(Input)
Reactor
(Output2)
Reactor
(Output1)


Check Mode
Output1 Open
Reactor Input Short
Output2 (Not Normal)
150
CHECKING MAIN PCB IN CASE OF
POWER OFF
Figure 82: Checking Main PCB (Communication IC). Figure 83: Multi-Meter (Note the
Probe Color).
Red
+%&
Black
Table 68: Main PCB (Communication IC) Measurements.

Multi-Meter Measured Value Images here are representative
Check Mode of system components. Actual
Black Red Normal Abnormal component appearance depends
IC26D ȍ IC26D GND (pin 5) IC26D Vcc (pin 8) NĹ Not Normal on model and system type.
Error Codes
PCB LOCATIONS
Control Box - Front Control Box - Back
Noise Filter
Main PCB
Inverter
Inverter PCB
Remove Screws
Comm. PCB Reactor
1. Remove outdoor unit front panel screws.

Outdoor Unit PCBs - Back of
2. Remove outdoor unit front panel. Outdoor Unit PCBs - Front of Control Box
• Check Main PCB Control Box
• Remove T/B R,S,T,N screws
• Disconnect Main PCB connector
• Remove control box front panel screws
• Remove control box front panel
• Check N/F, Inverter PCB Main PCB Inverter PCB Noise Filter IDU to ODU Cen. to ODU
Comm. PCB Comm. PCB
152
OUTDOOR UNIT PARTS
PCBs
Main PCB for ARUN024 to 053GSS4 Heat Pump Outdoor Units

HIGH PRESSURE SW MAIN EEV
AC_INPUT SC EEV
BASE PAN HEATER SW01D
SW01C
SW04C
4 WAY
SW03C
HOT GAS
SW02C
CN8
AIR
CN7
CN_INV
SUCTION/HEX/
DISCHARGE
SC_OUT/LIQUID
Parts
P_SEN_L
P_SEN_H
Main PCB for ARUN060GSS4 Heat Pump and ARUB060GSS4 Heat Recovery
Outdoor Units
4 WAY HEATER
AC_INPUT CN_INV
COMP_SW
CN_OPT_01
CN_OPT_02
CN_SVC
SC_OUT/SC_IN/LIQUID Main EEV
SUCTION/HEX/DISCHARGE
RESERVED1/ATR SC EEV
Actual component appearances
CN_HUMINITY P_SEN_L will differ depending on manufac-
P_SEN_H turing date, model, system type,
etc.
OUTDOOR UNIT PARTS
PCBs
PI-485 PCB for ARUN024 to 053GSS4 Indoor Communications PCB for

Heat Pump Outdoor Units ARUN024 to 053GSS4 Heat Pump
Outdoor Units
Noise Filter PCB for ARUN024 to Inverter PCB for ARUN024 to 053GSS4
053GSS4 Heat Pump Outdoor Units Heat Pump Outdoor Units
Actual component appearances will differ depending on manufacturing

date, model, system type, etc.
The fuse is not replaceable.
154
OUTDOOR UNIT PARTS
PCBs
Indoor Communications PCB Service PCB ARUN060GSS4 Heat

ARUN060GSS4 Heat Pump and Pump and ARUB060GSS4 Heat
ARUB060GSS4 Heat Recovery Recovery Outdoor Units
Outdoor Units
Parts
Noise Filter for ARUN060GSS4 Heat Inverter PCB for ARUN060GSS4 Heat
Pump and ARUB060GSS4 Heat Pump and ARUB060GSS4 Heat
Recovery Outdoor Units Recovery Outdoor Units
CN_MAIN
CN_FAN1
CN_FAN2
CN_U
CN_V
CN_W
CN_INPUT_L
CN_COIL1
CN_COIL2 CN_INPUT_N
Actual component appearances will differ depending on manufacturing

date, model, system type, etc.
The Danifuse is a TDR fuse; changed from the Bussman.
OUTDOOR UNIT PARTS
Control Box Parts
Control Box Parts for ARUN24GSS4 Heat Pump Outdoor Units
649950
268711C
268711D
268711A
268711B
261704
W6640
W6200
Table 69: Control Box Parts for ARUN24GSS4 Heat Pump Outdoor Units.
Part No. Description Color
263230A Subcooling Out Pipe + Liquid Pipe Yellow
263230B Suction Pipe + Heat Exchanger + Discharge Pipe Purple
263230C Air Temperature Sensor Green
Actual component appearances will differ depending on manufacturing date, model, system type, etc.
156
OUTDOOR UNIT PARTS
Control Box Parts
Control Box Parts for ARUN38 to 53GSS4 Heat Pump Outdoor Units
268711D
261704
649950
268711C
Parts
268711A
W6200
268711B
W6640
Table 70: Control Box Parts for ARUN38 to 53GSS4 Heat Pump Outdoor Units.
OUTDOOR UNIT PARTS
Control Box Parts
Control Box Parts for ARUN060GSS4 Heat Pump and ARUB060GSS4 Heat
Recovery Outdoor Units
649950
261704
268711C
268711A
W6200
268711D
268711B
268711E
W6640
W49200
Table 71: Control Box Parts for ARUN60GSS4 Heat Pump and ARUN60GSS4 Heat Recovery Outdoor Units.
158
OUTDOOR UNIT PARTS
Expanded Frame View
Expanded Frame View for ARUN24GSS4 Heat Pump Outdoor Units
435300
435512
549610
554031
137213A
546810 W4811
237202 349480
437211
Parts
437212
559010
550140 430410 137213B
435301
OUTDOOR UNIT PARTS
Expanded Frame View
Expanded Frame View for ARUN38 to 53GSS4 Heat Pump Outdoor Units
237204 435512
435300
549610
554031
554031
546810A
447910
237202
237205
349480
559010 135500
546810B
550140 437212
137213
435513
430410
435301
437211
160
OUTDOOR UNIT PARTS
Expanded Frame View
Expanded Frame View for ARUN060GSS4 Heat Pump and ARUB060GSS4

Heat Recovery Outdoor Units
237204A 435512
435300
549610
554031
554031
235512
546810A
447910
237202
Parts
237205
349480
559010 135500
546810B
137213
550140 437212
435513
430410
435301
437211
OUTDOOR UNIT PARTS
Expanded Piping View
Expanded Piping View for ARUN24GSS4 Heat Pump Outdoor Units
552113
552115
552120
55211G
561410A
W54102
552202 552209
165000A
661400
165000B
552200
552204
W6631
561410B W52240B
554160
W4986A
W54102 552203B
552203A
W52240A W52240C
* When ordering compressor part 54160, Butyl rubber

part W54102 must also be ordered. See diagram above
for an example on how to install the Butyl rubber to the 135500
W4986B
compressor.
162
OUTDOOR UNIT PARTS
Expanded Piping View for ARUN38 to 53GSS4 Heat Pump Outdoor Units
552113
552115
552209
561410B 165010B
Parts
552204
165010A
566001
561410A
552202
W52240A
W6631
148000
548490
552203A
552203B
552200
661400
W4986A 552116
552117
554160
55211G
W4986B
OUTDOOR UNIT PARTS
Expanded Piping View for ARUN060GSS4 Heat Pump Outdoor Units

55211G 552111 552115
552209
35211A 165000A
W50140
552120
561410 552202
265021
548490A
W6631
566001
661400
165000B 552200
552203B
552203A
554160
W4986A
W4986B
164
OUTDOOR UNIT PARTS
Expanded Piping View for ARUB060GSS4 Heat Recovery Outdoor Units

55211G 552111 552115
552209
35211A 165000A
552120 W50140
561410 552202
W6631
Parts
165000B
265021
661400
566001 552200
552203B
552203C
552203A
554160 548490A
W4986A
W4986B
20001747 ISO 9001: 2008
LG ELECTRONICS INC.
Refer to the Installation Manual posted on www.lghvac.com.
LG Electronics Products Support

1-888-865-3026 USA
LG Electronics, U.S.A., Inc.
Follow the prompts for HVAC products.
Air Conditioning Technologies
4300 North Point Parkway
Alpharetta, Georgia 30022 SM_MultiV_S_OutdoorUnits_10_18
www.lghvac.com Supersedes: SM_MultiV_S_OutdoorUnits_07_18

Service Manual: Variable Refrigerant Flow Outdoor Units 2 To 5 Tons

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SERVICE MANUAL

Variable Refrigerant Flow Outdoor Units

Do not throw away, destroy, or lose this manual.

For more technical materials such as submittals, catalogs, engineering,

Safety Precautions ............................................................................. 4-7 Troubleshooting Main Components ............................................. 76-86

This symbol indicates an action that must not be performed.

Periodically check that the outdoor frame is not damaged.

Properly insulate all cold surfaces to prevent “sweating.”

the equipment. placed on the power wiring during operation.

The information contained in this manual is intended for use 6HFXUHDOO¿HOGZLULQJFRQQHFWLRQVZLWKDSSURSULDWHZLUH

Outdoor Units (ODU)

Heat Recovery Units (HRU)

Outdoor Unit Functions

Outdoor Unit Functions

Outdoor Unit Functions

Outdoor Unit Functions

Indoor Heat Exchanger Indoor Heat Exchanger

High Temperature High Pressure Vapor

Temperature Liquid Pipe

Sub-Co o ling EEV Out doo r Unit

Press u re Sensor Temperature Sensor Check Valve Solenoid Va lv e

Indoor Heat Exchanger Indoor Heat Exchanger

High Temperature High Pressure Vapor

Outdoor Unit Functions

Outdoor Unit Hot Vapor Vapor Pipe

High Pressure Low

Sub-Coo ling EE V Outdoor Unit

Press u re Sensor Temperature Sensor Check Valve Solenoid Valve

Indoor Heat Exchanger Indoor Heat Exchanger

High Temperature High Pressure Vapor

Temperature Liquid Pipe

High Pressure Low

Sub-Co o ling EE V Outdoor Unit

Pr ess u re Sensor Temperature Sensor Check Valve Sole noid Va lve

High Temperature High Pressure Vapor

Indoor HEX EEV Indoor HEX EEV

Indoor Unit Indoor Unit

Outdoor Unit Functions

Pressure Sensor Temperature Sensor Check Valve Solenoid Valve

High Temperature High Pressure Vapor

Indoor HEX EEV Indoor HEX EEV

Indoor Unit Indoor Unit

Pressure Sensor Temperature Sensor Check Valve Solenoid Valve

High Temperature High Pressure Vapor

Indoor HEX EEV Indoor HEX EEV

Indoor Unit Indoor Unit

Outdoor Unit Functions

Pressure Sensor Temperature Sensor Check Valve Solenoid Valve

Indoor HEX EEV High Temperature High Pressure Vapor

Indoor HEX EEV s

Indoor HEX EEV

Strainer Low Pressure

Pressure Sensor Temperature Sensor Check Valve Solenoid Valve

Indoor HEX High Temperature High Pressure Vapor

Indoor HEX EEV s

Indoor HEX EEV

Outdoor Unit Functions

Strainer Low Pressure

Pressure Sensor Temperature Sensor Check Valve Solenoid Valve

&RRO+HDW6HOHFWRU)Q Figure 9: Cool / Heat Selector.