RXM-LV1B SM2

SiBE041434E
Service
Manual
Inverter Pair
Wall Mounted Type FTXM-K Series
[Applied Models]
z Inverter Pair : Heat Pump
SiBE041434E
Inverter Pair
Wall Mounted Type
FTXM-K Series
zHeat Pump
Indoor Unit
FTXM20K3V1B
FTXM25K3V1B
FTXM35K3V1B
FTXM42K3V1B
FTXM50K3V1B
Outdoor Unit
RXM20LV1B
RXM25LV1B
RXM35LV1B
RXM42LV1B
RXM50LV1B
i Table of Contents
SiBE041434E
1. Safety Cautions.......................................................................................v
1.1 Warnings and Cautions Regarding Safety of Workers.............................v
1.2 Warnings and Cautions Regarding Safety of Users................................ xi
2. Used Icons ........................................................................................... xiv
Part 1 List of Functions ................................................................ 1

1. Functions.................................................................................................2
Part 2 Specifications .................................................................... 3

1. Specifications ..........................................................................................4
Part 3 Printed Circuit Board Connector Wiring Diagram ............. 7

1. Indoor Unit...............................................................................................8
1.1 20/25 Class ..............................................................................................8
1.2 35/42/50 Class .......................................................................................10
2. Outdoor Unit..........................................................................................12
2.1 20/25/35 Class .......................................................................................12
2.2 42/50 Class ............................................................................................14
Part 4 Function and Control........................................................ 15

1. Main Functions......................................................................................16
1.1 Temperature Control ..............................................................................16
1.2 Frequency Principle................................................................................16
1.3 Airflow Direction Control.........................................................................18
1.4 Fan Speed Control for Indoor Unit .........................................................20
1.5 Program Dry Operation ..........................................................................21
1.6 Automatic Operation...............................................................................22
1.7 Thermostat Control.................................................................................23
1.8 NIGHT SET Mode ..................................................................................24
1.9 ECONO Operation .................................................................................24
1.10 INTELLIGENT EYE Operation (20/25 Class).........................................25
1.11 2-Area INTELLIGENT EYE Operation (35/42/50 Class) ........................26
1.12 Inverter POWERFUL Operation .............................................................28
1.13 Clock Setting ..........................................................................................29
1.14 WEEKLY TIMER Operation ...................................................................30
1.15 Other Functions......................................................................................36
2. Function of Thermistor ..........................................................................37
3. Control Specification .............................................................................38
3.1 Mode Hierarchy ......................................................................................38
3.2 Frequency Control..................................................................................38
3.3 Controls at Mode Changing / Start-up....................................................40
3.4 Discharge Pipe Temperature Control.....................................................42
3.5 Input Current Control..............................................................................43
3.6 Freeze-up Protection Control .................................................................44
3.7 Heating Peak-cut Control .......................................................................44
3.8 Outdoor Fan Control...............................................................................45
3.9 Liquid Compression Protection Function................................................45
3.10 Defrost Control .......................................................................................46
3.11 Electronic Expansion Valve Control .......................................................47
Table of Contents ii
SiBE041434E
3.12 Malfunctions ...........................................................................................50
Part 5 Remote Controller ............................................................ 51

1. 20/25 Class ...........................................................................................52
2. 35/42/50 Class ......................................................................................54
Part 6 Service Diagnosis............................................................. 56

1. General Problem Symptoms and Check Items .....................................57
2. Troubleshooting with LED .....................................................................58
2.1 Indoor Unit..............................................................................................58
2.2 Outdoor Unit ...........................................................................................58
3. Service Diagnosis .................................................................................59
4. Troubleshooting ....................................................................................62
4.1 Error Codes and Description ..................................................................62
4.2 Indoor Unit PCB Abnormality .................................................................63
4.3 Freeze-up Protection Control / Heating Peak-cut Control ......................64
4.4 Fan Motor (DC Motor) or Related Abnormality.......................................65
4.5 Thermistor or Related Abnormality (Indoor Unit)....................................68
4.6 Refrigerant Shortage ..............................................................................69
4.7 Low-voltage Detection or Over-voltage Detection..................................71
4.8 Signal Transmission Error (Between Indoor Unit and Outdoor Unit)......73
4.9 Unspecified Voltage (Between Indoor Unit and Outdoor Unit) ...............75
4.10 Outdoor Unit PCB Abnormality...............................................................76
4.11 OL Activation (Compressor Overload) ...................................................78
4.12 Compressor Lock ...................................................................................80
4.13 DC Fan Lock ..........................................................................................81
4.14 Input Overcurrent Detection ...................................................................82
4.15 Four Way Valve Abnormality..................................................................83
4.17 High Pressure Control in Cooling ...........................................................86
4.18 Compressor System Sensor Abnormality ..............................................87
4.19 Position Sensor Abnormality ..................................................................88
4.20 DC Voltage / Current Sensor Abnormality (20/25/35 Class Only)..........90
4.21 Thermistor or Related Abnormality (Outdoor Unit).................................91
4.22 Electrical Box Temperature Rise............................................................93
4.23 Radiation Fin Temperature Rise ............................................................94
4.24 Output Overcurrent Detection ................................................................95
5. Check ....................................................................................................97
5.1 Thermistor Resistance Check ................................................................97
5.2 Fan Motor Connector Output Check ......................................................98
5.3 Power Supply Waveforms Check...........................................................99
5.4 Electronic Expansion Valve Check.........................................................99
5.5 Four Way Valve Performance Check ...................................................100
5.6 Inverter Unit Refrigerant System Check...............................................100
5.7 Inverter Analyzer Check .......................................................................101
5.8 Rotation Pulse Check on the Outdoor Unit PCB ..................................102
5.9 Installation Condition Check.................................................................103
5.10 Discharge Pressure Check...................................................................104
5.11 Outdoor Fan System Check .................................................................104
5.12 Main Circuit Short Check......................................................................105
iii Table of Contents

SiBE041434E
5.13 Power Module Check ...........................................................................106
Part 7 Trial Operation and Field Settings................................. 108

1. Pump Down Operation........................................................................109
2. Forced Cooling Operation ...................................................................110
3. Trial Operation ....................................................................................111
4. Field Settings ......................................................................................112
4.1 When 2 Units are installed in 1 Room ..................................................112
4.2 Model Type Setting ..............................................................................112
4.3 Facility Setting (cooling at low outdoor temperature) ...........................113
4.4 Jumper Settings ...................................................................................114
5. Silicon Grease on Power Transistor / Diode Bridge............................115
Part 8 Appendix......................................................................... 116

1. Piping Diagrams..................................................................................117
1.1 Indoor Unit............................................................................................117
1.2 Outdoor Unit .........................................................................................119
2. Wiring Diagrams..................................................................................120
2.1 Indoor Unit............................................................................................120
2.2 Outdoor Unit .........................................................................................121
Table of Contents iv
Safety Cautions SiBE041434E
1. Safety Cautions
Be sure to read the following safety cautions before conducting repair work.
After the repair work is complete, be sure to conduct a test operation to ensure that the
equipment operates normally, and explain the cautions for operating the product to the
customer.
Caution Items The caution items are classified into Warning and Caution. The Warning items are
especially important since they can lead to death or serious injury if they are not followed
closely. The Caution items can also lead to serious accidents under some conditions if they
are not followed. Therefore, be sure to observe all the safety caution items described below.
Pictograms This symbol indicates the item for which caution must be exercised.
The pictogram shows the item to which attention must be paid.
This symbol indicates the prohibited action.
The prohibited item or action is shown in the illustration or near the symbol.
This symbol indicates the action that must be taken, or the instruction.
The instruction is shown in the illustration or near the symbol.
1.1 Warnings and Cautions Regarding Safety of Workers

Warning
Do not store the equipment in a room with successive fire sources (e.g.,
naked flame, gas appliance, electric heater).
Be sure to disconnect the power cable plug from the plug socket before
disassembling the equipment for repair.
Working on the equipment that is connected to the power supply may cause an
electrical shock.
If it is necessary to supply power to the equipment to conduct the repair or
inspecting the circuits, do not touch any electrically charged sections of the
equipment.
If the refrigerant gas is discharged during the repair work, do not touch
the discharged refrigerant gas.
The refrigerant gas may cause frostbite.
When disconnecting the suction or discharge pipe of the compressor at

the welded section, evacuate the refrigerant gas completely at a well-
ventilated place first.
If there is gas remaining inside the compressor, the refrigerant gas or
refrigerating machine oil discharges when the pipe is disconnected, and it may
cause injury.
If the refrigerant gas leaks during the repair work, ventilate the area.
The refrigerant gas may generate toxic gases when it contacts flames.
Be sure to discharge the capacitor completely before conducting repair

work.
The step-up capacitor supplies high-voltage electricity to the electrical
components of the outdoor unit.
A charged capacitor may cause an electrical shock.
v
SiBE041434E Safety Cautions
Warning
Do not start or stop the air conditioner operation by plugging or
unplugging the power cable plug.
Plugging or unplugging the power cable plug to operate the equipment may
cause an electrical shock or fire.
Be sure to wear a safety helmet, gloves, and a safety belt when working
at a high place (more than 2 m).
Insufficient safety measures may cause a fall accident.
In case of R-32 / R-410A refrigerant models, be sure to use pipes, flare

nuts and tools for the exclusive use of the R-32 / R-410A refrigerant.
The use of materials for R-22 refrigerant models may cause a serious accident
such as a damage of refrigerant cycle as well as an equipment failure.
Do not mix air or gas other than the specified refrigerant (R-32 / R-410A /
R-22) in the refrigerant system.
If air enters the refrigerating system, an excessively high pressure results,
causing equipment damage and injury.
Caution
Do not repair the electrical components with wet hands.
Working on the equipment with wet hands may cause an electrical shock.
Do not clean the air conditioner by splashing water.

Washing the unit with water may cause an electrical shock.
Be sure to provide the earth / grounding when repairing the equipment in

a humid or wet place, to avoid electrical shocks.
Be sure to turn off the power switch and unplug the power cable when
cleaning the equipment.
The internal fan rotates at a high speed, and may cause injury.
Be sure to conduct repair work with appropriate tools.

The use of inappropriate tools may cause injury.
Be sure to check that the refrigerating cycle section has cooled down
enough before conducting repair work.
Working on the unit when the refrigerating cycle section is hot may cause
burns.
vi
Caution
Use the welder in a well-ventilated place.
Using the welder in an enclosed room may cause oxygen deficiency.
Checking the area

Before beginning work, conduct safety checks to minimise the risk of ignition. When repairing
the refrigerating system, take the following precautions before work.
Work procedure
Work shall be conducted under a controlled procedure so as to minimise the risk of working in
the presence of R-32 or vapour.
General working area

All maintenance staff and others working in the local area shall be instructed on the nature of
work being carried out.
Work in confined spaces shall be avoided.
The area around the workspace shall be sectioned off. Ensure that the conditions within the
area have been made safe by control of flammable materials.
Checking for presence of refrigerant

The working area shall be checked with an appropriate refrigerant detector before and during
work, to ensure the technician is aware of potentially flammable atmospheres.
Ensure that the leak detection equipment being used is suitable for use with R-32, i.e. non-
sparking, adequately sealed or intrinsically safe.
Fire extinguishing equipment

If any hot work is to be conducted on the refrigeration equipment or any associated parts,
appropriate fire extinguishing equipment shall be made available at hand. Prepare a dry powder
or CO2 fire extinguisher adjacent to the working area.
No ignition sources
During work on a refrigeration system which involves exposing any piping work that contains or
has contained R-32, any sources of ignition shall not be used in a manner that may lead to the
risk of fire or explosion. All possible ignition sources, including cigarette smoking, should be
kept at a safe distance from the site of installation, repairing, or removing space. Before starting
work, the area around the equipment shall be examined to make sure that there are no
flammable hazard or ignition risks. No Smoking signs shall be displayed.
Ventilated area
Ensure that the working area is open or that it is adequately ventilated before work.
Adequate ventilation shall be maintained during the entire period of work.
The ventilation should disperse any released refrigerant and preferably discharge it into the
external atmosphere.
vii
Checking the refrigeration equipment

Where electrical components are to be changed, the new components shall be fit for the
purpose and have the correct specifications.
The manufacturer's maintenance and service guidelines shall be followed at all times.
If there are any unclear points, consult the manufacturer's technical department for assistance.
The following checks shall be applied to any installation work involving R-32:
• The amount of charge is in accordance with the size of the room where the refrigerant
containing parts are installed;
• The ventilation machinery and outlets are operating adequately and are not obstructed;
• If an indirect refrigerating circuit is being used, the secondary circuit shall be checked for
the presence of refrigerant;
• Marking on the equipment is visible and legible. Markings and signs that are illegible shall
be corrected;
• Refrigeration pipes or components are installed in a position where they are unlikely to be
exposed to any substance which may corrode refrigerant containing components, or the
refrigerant containing components are constructed of materials which are inherently
resistant to corrosion or are suitably protected against corrosion.
Checking electrical devices

Repair and maintenance to electrical components shall include initial safety checks and
component inspection procedures. In case there is any fault that could endanger safety, no
electrical supply shall be connected to the circuit until the fault is satisfactorily dealt with.
Initial safety checks shall include:
• that capacitors are discharged: this shall be done in a safe manner to avoid possibility of
sparking;
• that no live electrical components and wiring are exposed while charging, recovering or
purging the system;
• that the equipment is earthed at all times.
Repairs to sealed components

During repairs to sealed components, all electrical supplies shall be disconnected from the
equipment being worked upon before the removal of any sealed covers, etc. If it is absolutely
necessary to have power supplied to equipment during servicing, continuously operating leak
detection shall be installed at the most dangerous point of the system in order to warn of a
potentially hazardous situation.
Particular attention shall be paid to the following: ensure that working on electrical components
does not alter the casing in such a way that affects the level of protection including damage to
cables, excessive number of connections, terminals different from the original specification,
damage to seals, incorrect fitting of glands, etc.
Ensure that the equipment is mounted securely.
Ensure that seals or sealing materials have not degraded such that they no longer serve the
purpose of preventing the ingression of flammable atmospheres. Replacement parts shall be in
accordance with the manufacturer's specifications.
The use of silicon sealant may inhibit the effectiveness of some types of leak detection
equipment. Intrinsically safe components do not have to be isolated before working on them.
Repair to intrinsically safe components

Do not apply any permanent inductive or capacitance load to the circuit without ensuring that
this will not exceed the permissible voltage and current for the equipment in use.
Only intrinsically safe components can be worked on in the presence of a flammable
atmosphere.
The test apparatus shall be of correct rating.
Replace components only with parts specified by the manufacturer. Using other parts may
result in ignition of the refrigerant leaked into the atmosphere.
Wiring
Check that wiring is not subject to wear, corrosion, excessive pressure, vibration, sharp edges
or any other adverse environmental effects. The check shall also take into account the effects of
ageing or continuous vibration from sources such as compressors or fans.
viii
Detecting of R-32
Under no circumstances shall potential sources of ignition be used in the search for or detection
of refrigerant leaks. A halide torch (or any other detector using a naked flame) shall not be used.
Leak detection methods

The following leak detection methods can be applied for systems containing R-32.
Electronic leak detectors shall be used to detect R-32, but the sensitivity may not be adequate
or may need re-calibration (detection equipment shall be calibrated in a refrigerant-free area).
Ensure that the detector is not a potential source of ignition and that it is suitable for the
refrigerant used. Leak detection equipment shall be set to the percentage of the lower
flammability limit (LFL) of the refrigerant and calibrated to fit the refrigerant employed. The
appropriate percentage of gas (maximum 25%) shall be confirmed.
Leak detection fluids are suitable for use with most refrigerants but the use of detergents
containing chlorine shall be avoided as the chlorine may react with the refrigerant and corrode
the copper piping work.
If a leak is suspected, all naked flames shall be removed or extinguished.
If a refrigerant leakage which requires brazing is found, all of the refrigerant shall be recovered
from the system, or isolated (by means of shut off valves) in a part of the system remote from
the point of the leakage. Oxygen free nitrogen (OFN) shall then be purged through the system
both before and during the brazing process.
Removal and evacuation

When breaking the refrigerant circuit to make repairs or any other purpose, conventional
procedures may be used. However, flammability must be taken into consideration. The
following procedure shall be adhered to:
• Remove refrigerant;
• Purge the circuit with inert gas;
• Evacuate the inert gas;
• Purge again with inert gas;
• Carry out cutting or brazing of the circuit.
The refrigerant shall be recovered into the correct recovery cylinders. The system shall be
cleaned with OFN to render the unit safe. (= Flushing) This process may need to be repeated
several times. Compressed air or oxygen shall not be used for this task.
Flushing shall be achieved through breaking the vacuum by filling the system with OFN until the
working pressure is achieved, then venting the OFN into the atmosphere, and finally pulling the
system down to vacuum again. This process shall be repeated until no refrigerant remains
within the system. After the last OFN charge is finished, the system shall be vented down to
atmospheric pressure to enable work. This operation is especially important if brazing
operations on the piping work are to take place.
Ensure that the outlet for the vacuum pump is not close to any ignition sources and that there is
ventilation available.
Charging procedures
In addition to conventional charging procedures, the following requirements shall be met.
Ensure that the charging equipment to be used is not contaminated by different refrigerants.
Hoses or lines shall be as short as possible to minimise the amount of refrigerant contained in
them.
• Cylinders shall be kept upright.
• Ensure that the refrigeration system is earthed before charging the system with refrigerant.
• Label the system when charging is complete (if not already).
• Extreme care shall be taken not to overfill the refrigeration system.
Before recharging, the system shall be tested for leakage with OFN. On completion of charging,
the system shall be tested before commissioning. Follow up leakage test shall be carried out
before leaving the site.
ix
Decommissioning
Before carrying out this procedure, it is essential that the technician is completely familiar with
the equipment and all its details. It is recommended to train technicians so that all of the
refrigerant is recovered safely. In case analysis is required before re-using the reclaimed
refrigerant, an oil and refrigerant sample shall be taken before proceeding with
decommissioning. It is essential that electrical power is available before work.
a) Comprehend the equipment and its operation.
b) Isolate the system electrically.
c) Before starting work, ensure that:
• mechanical handling equipment is available if required, for handling refrigerant cylinders;
• protective equipment can be used in compliance with specifications;
• the recovery process is supervised by a competent person at all times;
• recovery equipment and cylinders conform to the appropriate standards.
d) Pump down the refrigerant system, if possible.
e) If vacuum can not be ensured, apply a manifold so that refrigerant can be removed from
various parts of the system.
f) Make sure that the cylinder is situated on the scale before recovery takes place.
g) Start the refrigerant recovery device and operate it in accordance with the manufacturer's
instructions.
h) Do not overfill cylinders. (Do not exceed 80% liquid charge volume).
i) Do not exceed the maximum working pressure of the cylinder, even temporarily.
j) When the cylinders have been filled correctly and the process is completed, make sure
that the cylinders and the equipment are removed from site promptly and all valves on the
equipment are closed.
k) Recovered refrigerant shall not be charged into another refrigeration system before it has
been cleaned and checked.
Labelling
Equipment shall be labelled stating that it has been decommissioned and emptied of refrigerant.
The label shall be dated and signed. Ensure that there are labels on the equipment stating the
equipment contains R-32.
Refrigerant recovery
When removing refrigerant from a system, either for servicing or decommissioning, it is
recommended to conduct training so that all refrigerants can be removed safely.
When transferring refrigerant into cylinders, ensure that only appropriate refrigerant recovery
cylinders are used.
Ensure that the correct number of cylinders for holding the total system charge are available. All
cylinders to be used must be designated for the recovered refrigerant and labelled for that
refrigerant (i.e. special cylinders for the recovery of refrigerant). Cylinders shall be equipped
with a pressure relief valve and associated shut-off valves in good working order. If possible,
empty recovery cylinders shall be cooled in a separate place before recovery is conducted.
The recovery equipment shall be in good working order with instructions concerning the
equipment at hand, and shall be suitable for the recovery of R-32. In addition, a set of calibrated
weighing scales shall be available and in good working order. Hoses shall be equipped with
leak-free disconnect couplings and in good condition. Before using the recovery device, check
that it has undergone proper maintenance, that it is in satisfactory working order, and that any
associated electrical components are sealed to prevent ignition in the event of a refrigerant
leakage. Consult manufacturer if in doubt.
The recovered refrigerant shall be returned to the refrigerant supplier in the correct recovery
cylinder, with the relevant Waste Transfer Note attached. Do not mix refrigerants in recovery
units and especially not in cylinders.
If compressors or compressor oil are to be removed, ensure that the refrigerant melted into the
oil has been evacuated to an acceptable level to make certain that R-32 does not remain within
the oil. The evacuation process shall be carried out before returning the compressor to the
supplier. Only electric heating to the compressor body shall be employed to accelerate this
process. Oil drained from the system shall be treated safely.
x
1.2 Warnings and Cautions Regarding Safety of Users

Warning
Do not store the equipment in a room with successive fire sources (e.g.,
naked flame, gas appliance, electric heater).
Be sure to use parts listed in the service parts list of the applicable model
and appropriate tools to conduct repair work. Never attempt to modify the
equipment.
The use of inappropriate parts or tools may cause an electrical shock,
excessive heat generation or fire.
If the power cable and lead wires have scratches or deteriorated, be sure
to replace them.
Damaged cable and wires may cause an electrical shock, excessive heat
generation or fire.
Do not use a joined power cable or extension cable, or share the same
power outlet with other electrical appliances, since it may cause an
electrical shock, excessive heat generation or fire.
Be sure to use an exclusive power circuit for the equipment, and follow
the local technical standards related to the electrical equipment, the
internal wiring regulations, and the instruction manual for installation
when conducting electrical work.
Insufficient power circuit capacity and improper electrical work may cause an
electrical shock or fire.
Be sure to use the specified cable for wiring between the indoor and
outdoor units.
Make the connections securely and route the cable properly so that there is no
force pulling the cable at the connection terminals.
Improper connections may cause excessive heat generation or fire.
When wiring between the indoor and outdoor units, make sure that the
terminal cover does not lift off or dismount because of the cable.
If the cover is not mounted properly, the terminal connection section may cause
an electrical shock, excessive heat generation or fire.
Do not damage or modify the power cable.

Damaged or modified power cable may cause an electrical shock or fire.
Placing heavy items on the power cable, and heating or pulling the power cable
may damage the cable.
Do not mix air or gas other than the specified refrigerant (R-32 / R-410A /
R-22) in the refrigerant system.
If air enters the refrigerating system, an excessively high pressure results,
causing equipment damage and injury.
If the refrigerant gas leaks, be sure to locate the leaking point and repair
it before charging the refrigerant. After charging refrigerant, make sure
that there is no refrigerant leak.
If the leaking point cannot be located and the repair work must be stopped, be
sure to perform pump-down and close the service valve, to prevent the
refrigerant gas from leaking into the room. The refrigerant gas itself is
harmless, but it may generate toxic gases when it contacts flames, such as fan
and other heaters, stoves and ranges.
xi
Warning
When relocating the equipment, make sure that the new installation site
has sufficient strength to withstand the weight of the equipment.
If the installation site does not have sufficient strength and if the installation
work is not conducted securely, the equipment may fall and cause injury.
Check to make sure that the power cable plug is not dirty or loose, then
insert the plug into a power outlet securely.
If the plug has dust or loose connection, it may cause an electrical shock or fire.
Be sure to install the product correctly by using the provided standard For unitary type
installation frame. only
Incorrect use of the installation frame and improper installation may cause the
equipment to fall, resulting in injury.
Be sure to install the product securely in the installation frame mounted For unitary type
on the window frame. only
If the unit is not securely mounted, it may fall and cause injury.
When replacing the coin battery in the remote controller, be sure to

dispose of the old battery to prevent children from swallowing it.
If a child swallows the coin battery, see a doctor immediately.
Caution
Installation of a leakage breaker is necessary in some cases depending
on the conditions of the installation site, to prevent electrical shocks.
Do not install the equipment in a place where there is a possibility of

combustible gas leaks.
If the combustible gas leaks and remains around the unit, it may cause a fire.
Check to see if the parts and wires are mounted and connected properly,
and if the connections at the soldered or crimped terminals are secure.
Improper installation and connections may cause excessive heat generation,
fire or an electrical shock.
If the installation platform or frame has corroded, replace it.

Corroded installation platform or frame may cause the unit to fall, resulting in
injury.
xii
Caution
Check the earth / grounding, and repair it if the equipment is not properly
earthed / grounded.
Improper earth / grounding may cause an electrical shock.
Be sure to measure the insulation resistance after the repair, and make
sure that the resistance is 1 MΩ or higher.
Faulty insulation may cause an electrical shock.
Be sure to check the drainage of the indoor unit after the repair.
Faulty drainage may cause the water to enter the room and wet the furniture
and floor.
Do not tilt the unit when removing it.

The water inside the unit may spill and wet the furniture and floor.
Be sure to install the packing and seal on the installation frame properly. For unitary type
If the packing and seal are not installed properly, water may enter the room and only
wet the furniture and floor.
xiii
SiBE041434E Used Icons
2. Used Icons
The following icons are used to attract the attention of the reader to specific information.
Icon Type of Description

Information
Warning A Warning is used when there is danger of personal injury.
Warning
Caution A Caution is used when there is danger that the reader, through
incorrect manipulation, may damage equipment, lose data, get
Caution an unexpected result or has to restart (part of) a procedure.
Note A Note provides information that is not indispensable, but may

nevertheless be valuable to the reader, such as tips and tricks.
Note:
Reference A Reference guides the reader to other places in this binder or

in this manual, where he/she will find additional information on a
specific topic.
xiv
SiBE041434E
Part 1
List of Functions
1. Functions.................................................................................................2
1 List of Functions
SiBE041434E Functions
1. Functions
FTXM35/42/50K3V1B
FTXM35/42/50K3V1B
RXM35/42/50LV1B
RXM35/42/50LV1B
FTXM20/25K3V1B
FTXM20/25K3V1B
RXM20/25LV1B
RXM20/25LV1B
Category Functions Category Functions
Basic Function Inverter (with inverter power control) z z Health & Clean Air-purifying filter — —
–10 –10 Photocatalytic deodorizing filter — —
Operation limit for cooling (°CDB)
~ 46 ~ 46
Air-purifying filter with photocatalytic — —
–15 –15 deodorizing function (option)
Operation limit for heating (°CWB) ~ 18 ~ 18
Titanium apatite photocatalytic air-
z z
PAM control z z purifying filter
Standby electricity saving z z Air filter (prefilter) z z
Compressor Oval scroll compressor — — Wipe-clean flat panel z z
Swing compressor z z Washable grille — —
Rotary compressor — — MOLD PROOF operation — —
Reluctance DC motor z z Heating dry operation — —
Comfortable Power-airflow flap z — Good-sleep cooling operation — —
Airflow
Power-airflow dual flaps — z Timer WEEKLY TIMER operation z z
Power-airflow diffuser — — 24-hour ON/OFF TIMER z z
Wide-angle louvers z z NIGHT SET mode z z
Auto-swing (up and down) z z Worry Free Auto-restart (after power failure) z z
(Reliability &
Auto-swing (right and left) — z Durability) Self-diagnosis (R/C, LED) z z
3-D airflow — z Wiring error check function — —
COMFORT AIRFLOW operation z z Anti-corrosion treatment of outdoor z z
Comfort Auto fan speed z z heat exchanger
Control
Flexibility Multi-split / split type compatible indoor
Indoor unit quiet operation z z unit — —
NIGHT QUIET mode (automatic) — — Flexible power supply correspondence — —

OUTDOOR UNIT QUIET operation High ceiling application — —
z z
(manual) Chargeless 10 m 10 m
INTELLIGENT EYE operation z — Either side drain (right or left) z z
2-area INTELLIGENT EYE operation — z Power selection — —
Quick warming function Facility setting (cooling at low outdoor
z z z z
(preheating operation) temperature)
Hot-start function z z Remote 5-room centralized controller (option) z z
Control
Automatic defrosting z z Remote control adaptor
(normal open pulse contact) (option) z z
Operation Automatic operation z z
Program dry operation z z Remote control adaptor z z
Fan only z z (normal open contact) (option)
Lifestyle New POWERFUL operation (non- — — DIII-NET compatible (adaptor) (option) z z
Convenience inverter)
Inverter POWERFUL operation z z Wireless LAN connection (option) z z
Priority-room setting — — Remote Wireless z z
Controller
COOL / HEAT mode lock — — Wired (option) z z
HOME LEAVE operation — —
ECONO operation z z
Indoor unit ON/OFF button z z
Signal receiving sign z z
R/C with back light z z
Temperature display — —
Note: z : Available
— : Not available
List of Functions 2
SiBE041434E
Part 2
Specifications
1. Specifications ..........................................................................................4
3 Specifications
SiBE041434E Specifications
1. Specifications
50 Hz, 220 - 230 - 240 V
Indoor Unit FTXM20K3V1B FTXM25K3V1B
Model RXM20LV1B RXM25LV1B
Outdoor Unit
Cooling Heating Cooling Heating
kW 2.0 (1.3 ~ 2.8) 2.5 (1.3 ~ 4.3) 2.5 (1.3 ~ 3.2) 2.8 (1.3 ~ 4.7)
Capacity Btu/h 6,800 (4,400 ~ 9,600) 8,500 (4,400 ~ 14,700) 8,500 (4,400 ~ 10,900) 9,600 (4,400 ~ 16,000)
Rated (Min. ~ Max.)
kcal/h — — — —
Moisture Removal L/h 1.1 — 1.2 —
Running Current (Rated) A 2.46 - 2.36 - 2.26 2.80 - 2.70 - 2.60 3.23 - 3.13 - 3.03 3.30 - 3.20 - 3.10
Power Consumption W 441 (320 ~ 760) 550 (310 ~ 1,120) 576 (320 ~ 1,000) 620 (310 ~ 1,410)
Rated (Min. ~ Max.)
Power Factor (Rated) % 81.4 - 81.3 - 81.4 89.3 - 88.6 - 88.1 81.0 - 79.9 - 79.2 85.4 - 84.2 - 83.3
EER (Cooling) / COP (Heating) W/W 4.53 4.55 4.34 4.52
Liquid mm φ 6.4 φ 6.4
Piping Gas mm φ 9.5 φ 9.5
Connections
Drain mm φ 18.0 φ 18.0
Heat Insulation Both Liquid and Gas Pipes Both Liquid and Gas Pipes
Max. Interunit Piping Length m 20 20
Max. Interunit Height Difference m 15 15
Chargeless m 10 10
Amount of Additional Charge of g/m 20 20
Refrigerant
Front Panel Color White White
H 8.8 (311) 9.5 (335) 9.1 (321) 10.0 (353)
M m³/min 6.7 (237) 7.8 (275) 7.0 (247) 8.0 (282)
Airflow Rate (cfm)
L 4.7 (166) 6.0 (212) 5.0 (177) 6.0 (212)
SL 3.9 (138) 4.3 (152) 3.9 (138) 4.3 (152)
Type Cross Flow Fan Cross Flow Fan
Fan Motor Output W 16 16
Speed Steps 5 Steps, Quiet, Auto 5 Steps, Quiet, Auto
Air Direction Control Right, Left, Horizontal, Downward Right, Left, Horizontal, Downward
Air Filter Removable, Washable, Mildew Proof Removable, Washable, Mildew Proof
Power Consumption (Rated) W 40 40 40 40
Temperature Control Microcomputer Control Microcomputer Control
Dimensions (H × W × D) mm 289 × 780 × 215 289 × 780 × 215
Packaged Dimensions (H × W × D) mm 274 × 850 × 346 274 × 850 × 346
Weight (Mass) kg 8 8
Gross Weight (Gross Mass) kg 12 12
Sound Pressure H / M / L / SL dB(A) 40 / 32 / 24 / 19 40 / 34 / 27 / 19 41 / 33 / 25 / 19 41 / 34 / 27 / 19
Level
Sound Power Level (H) dB 58 58 58 58
Outdoor Unit RXM20LV1B RXM25LV1B
Casing Color Ivory White Ivory White
Type Hermetically Sealed Swing Type Hermetically Sealed Swing Type
Compressor Model 1YC25FXD 1YC25FXD
Motor Output W 800 800
Type FW68DA FW68DA
Refrigerant Oil
Charge L 0.375 0.375
Type R-32 R-32
Refrigerant
Charge kg 0.72 0.72
H m³/min 33.5 (1,183) 29.0 (1,024) 33.5 (1,183) 29.0 (1,024)
Airflow Rate (cfm)
SL 29.3 (1,035) 25.6 (904) 29.3 (1,035) 25.6 (904)
Type Propeller Propeller
Fan
Power Consumption (Rated) W 401 510 536 580
Starting Current A 3.7 3.7
Sound Pressure H / SL dB(A) 46 / 43 47 / 44 46 / 43 47 / 44
Level
Drawing No. 3D092694B 3D092692A
Note: The data are based on the conditions shown in the table below. Conversion Formulae
Cooling Heating Piping Length
Indoor ; 27°CDB / 19°CWB Indoor ; 20°CDB kcal/h = kW × 860
Outdoor ; 35°CDB / 24°CWB Outdoor ; 7°CDB / 6°CWB 5m Btu/h = kW × 3412
cfm = m³/min × 35.3
Specifications 4
Specifications SiBE041434E
50 Hz, 220 - 230 - 240 V

Model RXM35LV1B RXM42LV1B
Outdoor Unit
kW 3.5 (1.4 ~ 4.0) 4.0 (1.4 ~ 5.2) 4.2 (1.7 ~ 5.0) 5.4 (1.7 ~ 6.0)
Capacity Btu/h 11,900 (4,800 ~ 13,600) 13,600 (4,800 ~ 17,700) 14,300 (5,800 ~ 17,100) 18,400 (5,800 ~ 20,500)
Rated (Min. ~ Max.)
kcal/h 3,010 (1,200 ~ 3,440) 3,440 (1,200 ~ 4,470) 3,610 (1,460 ~ 4,300) 4,640 (1,460 ~ 5,160)
Moisture Removal L/h 1.9 — 2.3 —
Power Consumption W 855 (350~ 1,190) 840 (340 ~ 1,460) 1,213 (320 ~ 2,330) 1,310 (400 ~ 1,980)
Rated (Min. ~ Max.)
EER (Cooling) / COP (Heating) W/W 4.09 4.76 3.46 4.12
Liquid mm φ 6.4 φ 6.4
Piping Gas mm φ 9.5 φ 12.7
Connections
Drain mm φ 18.0 φ 18.0
Heat Insulation Both Liquid and Gas Pipes Both Liquid and Gas Pipes
Max. Interunit Piping Length m 20 30
Max. Interunit Height Difference m 15 20
Chargeless m 10 10
Amount of Additional Charge of g/m 20 20
Refrigerant
Front Panel Color White White
H 11.2 (395) 12.1 (427) 11.2 (395) 12.4 (438)
M m³/min 8.5 (300) 9.3 (328) 9.1 (321) 10.0 (353)
Airflow Rate (cfm)
L 5.8 (205) 6.5 (230) 7.0 (247) 7.8 (275)
SL 4.1 (145) 4.2 (148) 4.1 (145) 5.2 (184)
Type Cross Flow Fan Cross Flow Fan
Fan Motor Output W 23 23
Speed Steps 5 Steps, Quiet, Auto 5 Steps, Quiet, Auto
Air Direction Control Right, Left, Horizontal, Downward Right, Left, Horizontal, Downward
Air Filter Removable, Washable, Mildew Proof Removable, Washable, Mildew Proof
Power Consumption (Rated) W 26 - 26 - 26 28 - 28 - 28 24 - 24 - 24 30 - 30 - 30
Temperature Control Microcomputer Control Microcomputer Control
Sound Pressure H / M / L / SL dB(A) 45 / 37 / 29 / 19 45 / 39 / 29 / 19 45 / 39 / 33 / 21 45 / 39 / 33 / 22
Level
Outdoor Unit RXM35LV1B RXM42LV1B
Casing Color Ivory White Ivory White
Type Hermetically Sealed Swing Type Hermetically Sealed Swing Type
Compressor Model 1YC25FXD 2YC40GXD
Motor Output W 800 1,300
Type FW68DA FW68DA
Refrigerant Oil
Charge L 0.375 0.650
Type R-32 R-32
Refrigerant
Charge kg 0.8 1.50
H m³/min 36.0 (1,271) 28.6 (1,010) 48.5 (1,713) 40.4 (1,427)
Airflow Rate (cfm)
SL 29.3 (1,035) 25.6 (904) 38.5 (1,359) 34.3 (1,211)
Type Propeller Propeller
Fan
Power Consumption (Rated) W 829 812 1,189 1,280
Starting Current A 4.4 6.6
Sound Pressure H / SL dB(A) 49 / 44 49 / 45 48 / 44 48 / 45
Level
Drawing No. 3D092691A 3D092693A
Note: The data are based on the conditions shown in the table below.
Conversion Formulae
kcal/h = kW × 860
Indoor ; 27°CDB / 19°CWB Indoor ; 20°CDB 5m Btu/h = kW × 3412
Outdoor ; 35°CDB / 24°CWB Outdoor ; 7°CDB / 6°CWB cfm = m³/min × 35.3
5 Specifications
SiBE041434E Specifications
50 Hz, 220 - 230 - 240 V

Indoor Unit FTXM50K3V1B
Model RXM50LV1B
Outdoor Unit
Cooling Heating
kW 5.02 (1.70 ~ 5.30) 5.80 (1.70 ~ 6.50)
Capacity Btu/h 17,100 (5,800 ~ 18,100) 19,800 (5,800 ~ 22,200)
Rated (Min. ~ Max.)
kcal/h 4,300 (1,460 ~ 4,560) 4,990 (1,460 ~ 5,590)
Moisture Removal L/h 2.8 —
Running Current (Rated) A 6.91 - 6.60 - 6.28 6.80 - 6.50 - 6.20
Power Consumption W 1,476 (350 ~ 1,810) 1,450 (300 ~ 2,000)
Rated (Min. ~ Max.)
Power Factor (Rated) % 97.1 - 97.3 - 97.9 96.9 - 97.0 - 97.4
EER (Cooling) / COP (Heating) W/W 3.40 4.00
Liquid mm φ 6.4
Piping Gas mm φ 12.7
Connections
Drain mm φ 18.0
Heat Insulation Both Liquid and Gas Pipes
Max. Interunit Piping Length m 30
Max. Interunit Height Difference m 20
Chargeless m 10
Amount of Additional Charge of g/m 20
Refrigerant
Indoor Unit FTXM50K3V1B
Front Panel Color White
H 11.9 (420) 13.3 (470)
M m³/min 9.6 (339) 10.8 (381)
Airflow Rate (cfm)
L 7.4 (261) 8.4 (297)
SL 4.5 (159) 5.5 (194)
Type Cross Flow Fan
Fan Motor Output W 23
Speed Steps 5 Steps, Quiet, Auto
Air Direction Control Right, Left, Horizontal, Downward
Air Filter Removable, Washable, Mildew Proof
Power Consumption (Rated) W 26 - 26 - 26 32 - 32 - 32
Temperature Control Microcomputer Control
Dimensions (H × W × D) mm 298 × 900 × 215
Packaged Dimensions (H × W × D) mm 290 × 977 × 371
Weight (Mass) kg 11
Gross Weight (Gross Mass) kg 15
Sound Pressure H / M / L / SL dB(A) 46 / 40 / 34 / 23 47 / 40 / 34 / 24
Level
Sound Power Level (H) dB 60 60
Outdoor Unit RXM50LV1B
Casing Color Ivory White
Type Hermetically Sealed Swing Type
Compressor Model 2YC40GXD
Motor Output W 1,300
Type FW68DA
Refrigerant Oil
Charge L 0.65
Type R-32
Refrigerant
Charge kg 1.50
H m³/min 50.4 (1,780) 40.4 (1,427)
Airflow Rate (cfm)
SL 38.5 (1,359) 34.3 (1,211)
Type Propeller
Fan
Motor Output W 68
Power Consumption (Rated) W 1,450 1,418
Starting Current A 6.6
Dimensions (H × W × D) mm 735 × 825 × 300
Packaged Dimensions (H × W × D) mm 792 × 960 × 390
Weight (Mass) kg 44
Gross Weight (Gross Mass) kg 48
Sound Pressure H / SL dB(A) 48 / 44 48 / 45
Level
Sound Power Level (H) dB 62 62
Drawing No. 3D092682A
Note: The data are based on the conditions shown in the table below.
Conversion Formulae
kcal/h = kW × 860
Indoor ; 27°CDB / 19°CWB Indoor ; 20°CDB 5m Btu/h = kW × 3412
Outdoor ; 35°CDB / 24°CWB Outdoor ; 7°CDB / 6°CWB cfm = m³/min × 35.3
Specifications 6
SiBE041434E
Part 3
Printed Circuit Board
Connector Wiring Diagram
1. Indoor Unit...............................................................................................8
1.1 20/25 Class ..............................................................................................8
1.2 35/42/50 Class .......................................................................................10
2. Outdoor Unit..........................................................................................12
2.1 20/25/35 Class .......................................................................................12
2.2 42/50 Class ............................................................................................14
7 Printed Circuit Board Connector Wiring Diagram

SiBE041434E Indoor Unit
1. Indoor Unit
1.1 20/25 Class
Control PCB
(PCB1) 1) S6 Connector for swing motor (horizontal blade)
2) S25 Connector for INTELLIGENT EYE sensor PCB
3) S26 Connector for display PCB
4) S32 Connector for indoor heat exchanger thermistor
5) S200 Connector for DC fan motor
6) S403 Connector for adaptor PCB (option)
7) FG1, FG2 Connector for terminal board (frame ground)
8) H1, H2, H3 Connector for terminal board (indoor - outdoor transmission)
9) V1 Varistor
10)JA Address setting jumper
∗ Refer to page 112 for detail.
11)JB Fan speed setting when compressor stops for thermostat OFF
12)JC Power failure recovery function (auto-restart)
13)LED A LED for service monitor (green)
14)FU1 (F1U) Fuse (3.15 A, 250 V)
S32
S26 S6
JA JC JB
LED A
S25
S200
S403
FU1
V1
FG1, FG2
H1 H3 H2
2P297453-2
Caution Replace the PCB if you accidentally cut the jumpers other than JA, JB, and JC.
Jumpers are necessary for electronic circuit. Improper operation may occur if you cut any of
them.
Note: The symbols in the parenthesis are the names on the appropriate wiring diagram.
Printed Circuit Board Connector Wiring Diagram 8

Indoor Unit SiBE041434E
Display PCB
(PCB2) 1) S27 Connector for control PCB
2) SW1 (S1W) Forced cooling operation ON/OFF button
3) LED1 (H1P) LED for operation (green)
4) LED2 (H2P) LED for timer (yellow)
5) LED3 (H3P) LED for INTELLIGENT EYE (green)
6) RTH1 (R1T) Room temperature thermistor
S27
SW1 LED3 LED2 LED1
(Solder side)
RTH1
3P185701-3
INTELLIGENT
EYE Sensor PCB 1) S36 Connector for control PCB
(PCB3)
S36
3P296737-1

SiBE041434E Indoor Unit
1.2 35/42/50 Class

Control PCB
(PCB1) 1) S1 Connector for DC fan motor
2) S21 Connector for centralized control (HA)
3) S25 Connector for INTELLIGENT EYE sensor PCB
4) S32 Indoor heat exchanger thermistor
5) S41 Connector for swing motors
6) S46 Connector for display PCB
7) S47 Connector for signal receiver PCB
8) H1, H2, H3, Connector for terminal board
FG
9) JA Address setting jumper
10) JB Fan speed setting when compressor stops for thermostat OFF
11) JC Power failure recovery function (auto-restart)
12) LED A LED for service monitor (green)
13) FU1 (F1U), Fuse (3.15 A, 250 V)
FU2
14) V1 Varistor
S41 S1
S32 FG
H3 H2 H1
LED A FU1
FU2
S46
S25 V1
JC JA JB
S21
S47
2P206687-8
Caution Replace the PCB if you accidentally cut the jumpers other than JA, JB, and JC.
them.

Indoor Unit SiBE041434E
Signal Receiver
PCB (PCB2) 1) S48 Connector for control PCB
S48
3P210728-1
Display PCB
(PCB3) 1) S49 Connector for control PCB
2) SW1 (S1W) Forced cooling operation ON/OFF button
3) LED1 (H1P) LED for operation (green)
4) LED2 (H2P) LED for timer (yellow)
5) LED3 (H3P) LED for INTELLIGENT EYE (green)
6) RTH1 (R1T) Room temperature thermistor
RTH1 SW1
LED3 LED2 LED1
S49
3P210728-1
INTELLIGENT
EYE Sensor PCB 1) S26 Connector for control PCB
(PCB4)
S26
3EB86013-1

SiBE041434E Outdoor Unit
2. Outdoor Unit
2.1 20/25/35 Class
Main PCB (PCB2)
1) S10 Connector for filter PCB
2) S20 Connector for electronic expansion valve coil
3) S40 Connector for overload protector
5) S80 Connector for four way valve coil
6) S90 Connector for thermistors
(outdoor temperature, outdoor heat exchanger, discharge pipe)
7) S100 Connector for forced operation button PCB
8) HL3, HN3 Connector for filter PCB
9) HR2 Connector for reactor
10) U, V, W Connector for compressor
11) FU2 Fuse (3.15 A, 250 V)
13) V1 Varistor
14) J4 Jumper for facility setting
15) J5 Jumper for improvement of defrost performance
U V W
S10 J5 J4 S90 LED A
S70
S40
HR2
S20
S80
HL3
V1
HN3
FU2 S100
2P358715-5
Caution Replace the PCB if you accidentally cut a wrong jumper.

them.

Outdoor Unit SiBE041434E
Filter PCB (PCB1)

1) S11 Connector for main PCB
2) AC1, AC2, S Connector for terminal board
3) E1, E2 Terminal for earth wire
4) HL2, HN2 Connector for main PCB
5) HR1 Connector for reactor
6) FU1 Fuse (3.15 A, 250 V)
7) FU3 Fuse (20 A, 250 V)
8) V2, V3 Varistor
HR1 E1, E2
HN2
AC2
V2 V3 AC1
S11
FU3
HL2 FU1
3P254234-7
Forced Operation
Button PCB 1) S110 Connector for main PCB
(PCB3)
S110
3P255755-2
The switch SW1 has no function.

SiBE041434E Outdoor Unit
2.2 42/50 Class

Main PCB (PCB1)
1) S20 Connector for electronic expansion valve coil
2) S40 Connector for overload protector
4) S80 Connector for four way valve coil
5) S90 Connector for thermistors
(outdoor temperature, outdoor heat exchanger, discharge pipe)
6) HL1, HN1, S Connector for terminal board
7) E1, E2 Terminal for earth wire
8) U, V, W Connector for compressor
9) FU1, FU2 Fuse (3.15 A, 250 V)
10) FU3 Fuse (30 A, 250 V)
12) V1, V2, V3 Varistor
13) J6 Jumper for facility setting
14) J8 Jumper for improvement of defrost performance
FU3 HL1, HN1, S

E1, E2
S80 S20 S40 S90 J8 J6
V3
LED A
V2
FU1
V1
U, V, W
FU2
S70
2P356484-10

them.

SiBE041434E
Part 4
Function and Control
1. Main Functions......................................................................................16
1.1 Temperature Control ..............................................................................16
1.2 Frequency Principle................................................................................16
1.3 Airflow Direction Control.........................................................................18
1.4 Fan Speed Control for Indoor Unit .........................................................20
1.5 Program Dry Operation ..........................................................................21
1.6 Automatic Operation...............................................................................22
1.7 Thermostat Control.................................................................................23
1.8 NIGHT SET Mode ..................................................................................24
1.9 ECONO Operation .................................................................................24
1.10 INTELLIGENT EYE Operation (20/25 Class).........................................25
1.11 2-Area INTELLIGENT EYE Operation (35/42/50 Class) ........................26
1.12 Inverter POWERFUL Operation .............................................................28
1.13 Clock Setting ..........................................................................................29
1.14 WEEKLY TIMER Operation ...................................................................30
1.15 Other Functions......................................................................................36
2. Function of Thermistor ..........................................................................37
3. Control Specification .............................................................................38
3.1 Mode Hierarchy ......................................................................................38
3.2 Frequency Control..................................................................................38
3.3 Controls at Mode Changing / Start-up....................................................40
3.5 Input Current Control..............................................................................43
3.6 Freeze-up Protection Control .................................................................44
3.7 Heating Peak-cut Control .......................................................................44
3.8 Outdoor Fan Control...............................................................................45
3.9 Liquid Compression Protection Function................................................45
3.10 Defrost Control .......................................................................................46
3.11 Electronic Expansion Valve Control .......................................................47
3.12 Malfunctions ...........................................................................................50
15 Function and Control

SiBE041434E Main Functions
1. Main Functions
1.1 Temperature Control
Definitions of The definitions of temperatures are classified as following.
Temperatures
Room temperature: temperature of lower part of the room
Set temperature: temperature set by remote controller
Room thermistor temperature: temperature detected by room temperature thermistor
Target temperature: temperature determined by microcomputer
Target temperature
Room thermistor temperature
Set temperature
Room temperature
(R12321)
Temperature The temperature of the room is detected by the room temperature thermistor. However, there is
Control a difference between the temperature detected by room temperature thermistor and the
temperature of lower part of the room, depending on the type of the indoor unit or installation
condition. Practically, the temperature control is done by the target temperature appropriately
adjusted for the indoor unit and the temperature detected by room temperature thermistor.
1.2 Frequency Principle

Control The frequency of the compressor is controlled by the following 2 parameters:
Parameters The load condition of the operating indoor unit
The difference between the room thermistor temperature and the target temperature
The target frequency is adapted by additional parameters in the following cases:

Frequency restrictions
Initial settings
Forced cooling operation
Inverter Principle To regulate the capacity, a frequency control is needed. The inverter makes it possible to
control the rotation speed of the compressor. The following table explains the inverter principle:
Phase Description
1 The supplied AC power source is converted into the DC power source for the present.
2 The DC power source is reconverted into the three phase AC power source with variable
frequency.
When the frequency increases, the rotation speed of the compressor increases resulting
in an increase of refrigerant circulation. This leads to a larger amount of heat exchange
per unit.
When the frequency decreases, the rotation speed of the compressor decreases
resulting in a decrease of refrigerant circulation. This leads to a smaller amount of heat
exchange per unit.
Function and Control 16

Main Functions SiBE041434E
The following drawing shows a schematic view of the inverter principle:
Refrigerant circulation rate (high)
high speed
Amount of heat Amount of heat
exchanged air (large) high f exchanged air (large)
power
power
DC
AC
Amount of heat low f Amount of heat
exchanged air (small) exchanged air (small)
low speed
freq= 50 Hz capacity=
constant 60 Hz freq=variable variable
Refrigerant circulation rate (low) (R2812)
Inverter Features The inverter provides the following features:

The regulating capacity can be changed according to the changes in the outdoor
temperature and cooling / heating load.
Quick heating and quick cooling
The rotation speed of the compressor is increased when starting the heating (or cooling).
This enables to reach the set temperature quickly.
Even during extreme cold weather, high capacity is achieved. It is maintained even when the
outdoor temperature is 2°C.
Comfortable air conditioning
A fine adjustment is integrated to keep the room temperature constant.
Energy saving heating and cooling
Once the set temperature is reached, the energy saving operation enables to maintain the
room temperature at low power.
Frequency Limits The following functions regulate the minimum and maximum frequency:
Frequency Functions
Low Four way valve operation compensation. Refer to page 41.
High Compressor protection function. Refer to page 41.
Discharge pipe temperature control. Refer to page 42.
Input current control. Refer to page 43.
Freeze-up protection control. Refer to page 44.
Heating peak-cut control. Refer to page 44.
Defrost control. Refer to page 46.
Forced Cooling Refer to page 110 for detail.

Operation

1.3 Airflow Direction Control

Power-Airflow The large flap sends a large volume of air downward to the floor and provides an optimum
(Dual) Flap(s) control in cooling, dry, and heating operation.
<Cooling / Dry>
During cooling or dry operation, the flap retracts into the indoor unit. Then, cool air can be blown
far and distributed all over the room.
<Heating>
During heating operation, the large flap directs airflow downward to spread the warm air to the
entire room.
Wide-Angle The louvers, made of elastic synthetic resin, provide a wide range of airflow that guarantees
Louvers comfortable air distribution.
Auto-Swing The following table explains the auto-swing process for cooling, dry, heating, and fan:
Flap (up and down) Louver
Cooling / Dry Fan Heating (right and left)
20/25 5˚ 15˚ –
class
45˚ (R11256)
45˚ (R11257)
10˚ 10˚ 10˚

60˚ 60˚
35/42/50 10˚ 10˚
class 30˚ ˚
45
˚ 45
60˚ 60˚ 65˚
(R21332) (R18422) (R18423) (R11404)

3-D Airflow 35/42/50 class only

Alternative repetition of vertical and horizontal swing motions enables uniform air-conditioning of
the entire room.
When the horizontal swing and vertical swing are both set to automatic operation, the airflow
becomes 3-D airflow. The horizontal and vertical swing motions are alternated and the airflow
direction changes in the order shown in the following diagram.
(1) The louvers move from the right to the left.

(2) The flaps move downward.
(3) The louvers move from the left to the right.
(4) The flaps move upward.
(1)
(2)
(4)
(3)
(R19554)
COMFORT The flap is controlled not to blow the air directly at the people in the room.
AIRFLOW Cooling / Dry Heating
Operation
20/25 0˚
class
50˚
(R11259) (R11258)
35/42/50
class 5˚ 70˚
(R21333) (R21334)

1.4 Fan Speed Control for Indoor Unit

Outline Phase control and fan speed control contains 9 steps: LLL, LL, SL, L, ML, M, MH, H, and HH.
The airflow rate can be automatically controlled depending on the difference between the room
thermistor temperature and the target temperature.
Automatic Fan In automatic fan speed operation, the step SL is not available.
Speed Control Step Cooling Heating
LLL
LL
L
ML
M
MH
H
HH (POWERFUL) (R11681) (R6834)
= The airflow rate is automatically controlled within this range when the FAN setting
button is set to automatic.
<Cooling>
The following drawing explains the principle of fan speed control for cooling.
Room thermistor temperature – target temperature

Fan speed MH*
+3°C
+2.5°C M
+2°C
+1.5°C ML
+1°C
+0.5°C L
(R14588)
*The upper limit is M tap for 30 minutes from the operation start.
<Heating>
In heating operation, the fan speed is regulated according to the indoor heat exchanger
temperature and the difference between the room thermistor temperature and the target
temperature.
COMFORT The fan speed is controlled automatically.

AIRFLOW The latest command has the priority between POWERFUL and COMFORT AIRFLOW.
Operation

1.5 Program Dry Operation

Outline Program dry operation removes humidity while preventing the room temperature from lowering.
Since the microcomputer controls both the temperature and airflow rate, the temperature
adjustment and FAN setting buttons are inoperable.
Detail The microcomputer automatically sets the temperature and airflow rate. The difference between
the room thermistor temperature at start-up and the target temperature is divided into two
zones. Then, the unit operates in an appropriate capacity for each zone to maintain the
temperature and humidity at a comfortable level.
Room thermistor Target temperature Thermostat OFF point Thermostat ON point
temperature at start-up X Y Z
X – 0.5ºC
or
24ºC or more X – 2.5ºC Y + 0.5ºC (zone B)
Room thermistor continues for 10 min.
23.5ºC temperature at start-up X – 0.5ºC
X – 2.0ºC or
~
Y + 0.5ºC (zone B)
18ºC continues for 10 min.
X – 0.5ºC = 17.5ºC
17.5ºC or
18ºC X – 2.0ºC
Y + 0.5ºC (zone B)
~
continues for 10 min.
Zone C = Thermostat ON Z
Zone B
Zone B
Y
+0.5ºC
Zone A = Thermostat OFF
(R11581)

1.6 Automatic Operation

Outline Automatic Cooling / Heating Function
When the automatic operation is selected with the remote controller, the microcomputer
automatically determines the operation mode as cooling or heating according to the room
temperature and the set temperature at start-up.
The unit automatically switches the operation mode to maintain the room temperature at the set
temperature.
Detail Ts: set temperature (set by remote controller)

Tt: target temperature (determined by microcomputer)
Tr: room thermistor temperature (detected by room temperature thermistor)
C: correction value
1. The set temperature (Ts) determines the target temperature (Tt).

(Ts = 18 ~ 30°C).
2. The target temperature (Tt) is calculated as;
Tt = Ts + C
where C is the correction value.
C = 0°C
3. Thermostat ON/OFF point and operation mode switching point are as follows.
Tr means the room thermistor temperature.
(1) Heating → Cooling switching point:
Tr ≥ Tt + 2.5°C (20/25 class)
Tr ≥ Tt + 3.0°C (35/42/50 class)
(2) Cooling → Heating switching point:
Tr < Tt – 2.5°C
(3) Thermostat ON/OFF point is the same as the ON/OFF point of cooling or heating
operation.
4. During initial operation
Tr ≥ Ts : Cooling operation
Tr < Ts : Heating operation
20/25 class
Cooling Operation
Target temperature + 2.5˚C
Target temperature + 1.5˚C

Target temperature – 2.0˚C
= Thermostat OFF
= Thermostat OFF
Heating Operation (R11893)
Ex: When the target temperature is 25°C

Cooling → 23°C: Thermostat OFF → 22°C: Switch to heating
Heating → 26.5°C: Thermostat OFF → 27.5°C: Switch to cooling
35/42/50 class
Cooling Operation Target temperature + 3.0˚C
Target temperature – 2.0˚C Target temperature + 2.0˚C

= Thermostat OFF = Thermostat OFF
Heating Operation (R11892)
Ex: When the target temperature is 25°C

Cooling → 23°C: Thermostat OFF → 22°C: Switch to heating
Heating → 27°C: Thermostat OFF → 28°C: Switch to cooling

1.7 Thermostat Control

Outline Thermostat control is based on the difference between the room thermistor temperature and the
target temperature.
Detail Thermostat OFF Condition

The temperature difference is in the zone A.
Thermostat ON Conditions
The temperature difference returns to the zone C after being in the zone A.
The system resumes from defrost control in any zones except A.
The operation turns on in any zones except A.
The monitoring time has passed while the temperature difference is in the zone B.
(Cooling / Dry: 10 minutes, Heating: 10 seconds)
<Cooling / Dry>

ON
Cooling : –0.5˚C
Dry : –0.5˚C
C
–1.5˚C
B
Cooling : –2.0˚C
Dry : –2.5 ~ –2.0˚C
A
OFF
(R12319)
<Heating>
20/25 class
OFF
A
1.5˚C
B
1.0˚C
C
0˚C
ON (R12320)
35/42/50 class
OFF Room thermistor temperature – target temperature
A
2.0˚C
B
1.5˚C
C
0.5˚C
ON (R11894)
Refer to Temperature Control on page 16 for detail.

1.8 NIGHT SET Mode

Outline When the OFF TIMER is set, NIGHT SET Mode is automatically activated. NIGHT SET Mode
keeps the airflow rate setting.
Detail NIGHT SET Mode continues operation at the target temperature for the first one hour, then
automatically raises the target temperature slightly in the case of cooling, or lowers it slightly in
the case of heating. This prevents excessive cooling in summer and excessive heating in winter
to ensure comfortable sleeping conditions, and also conserves electricity.
<Cooling>
0.5˚C
Target temperature
Operation stops
1 hour at the set hours
TIMER operation +0.5˚C
NIGHT SET Mode ON temperature shift
(R18917)
<Heating>
Target temperature
2˚C
1 hour
TIMER operation –2˚C

NIGHT SET Mode ON temperature shift (R19386)
1.9 ECONO Operation

Outline ECONO operation reduces the maximum operating current and the power consumption.
This operation is particularly convenient for energy-saving. It is also a major bonus when
breaker capacity does not allow the use of multiple electrical devices and air conditioners.
It can be easily activated by pushing the ECONO button on the wireless remote controller.
Detail When this function is activated, the maximum capacity also decreases.
The remote controller can send the ECONO command when the unit is in cooling, heating,
dry, or automatic operation. This function can only be set when the unit is running. Pressing
the ON/OFF button on the remote controller cancels the function.
This function and POWERFUL operation cannot be used at the same time. The latest
command has the priority.
Maximum during normal operation

Power
consumption
and current Normal operation
Maximum during ECONO operation
ECONO Operation
Time
(R19427)

1.10 INTELLIGENT EYE Operation (20/25 Class)

Outline This function detects the presence of humans in the room with a motion sensor (INTELLIGENT
EYE) and reduces the capacity when there is nobody in the room in order to save electricity.
Detail 1. Detection method by INTELLIGENT EYE

If the sensor detects the outputs
10 times/sec. or more, it judges
humans are in the room.
sampling (20 msec.)
1 sec.
High
Sensor output
Low
Human motion
Human detection ON
signal OFF (R19471)
The sensor detects human motion by receiving infrared rays and displays the pulse wave
output.
The microcomputer in the indoor unit carries out a sampling every 20 msec. and if it detects
10 cycles of the wave in 1 second in total, it judges humans are in the room as the motion
signal is ON.
The sensor may detect human motion with up to 20 msec. latency.
2. The motions (in cooling)

within within
20 min. 20 min. within
20 min. 20 min.
Human detection ON
signal OFF
↑ ↑ ↑
Reset Reset Reset
Target temperature
Remote controller ON
INTELLIGENT OFF
EYE button
Operation ON
OFF
Set speed Set speed
Fan speed (+)
OFF
(R19414)
In FAN operation, the fan speed is reduced by 60 rpm.

When the microcomputer does not have a signal from the sensor in 20 minutes, it judges
that nobody is in the room and operates the unit at a temperature shifted from the target
temperature. (Cooling / Dry: 1 ~ 2°C higher, Heating: 2°C lower, Auto: according to the
operation mode at that time.)
Note: For dry operation, the temperature cannot be set with a remote controller, but the target
temperature is shifted internally.

1.11 2-Area INTELLIGENT EYE Operation (35/42/50 Class)

Outline The following functions can be performed by a motion sensor (INTELLIGENT EYE).
1. Reduction of the capacity when there is nobody in the room in order to save electricity
(energy saving operation)
2. Dividing the room into plural areas and detecting existence of humans in each area.
Moving the airflow direction to the area with no human automatically to avoid direct airflow
on humans.
Detail 1. Detection method of INTELLIGENT EYE
If the sensor detects the outputs 10 times/sec.

sampling (20 msec.) or more, it judges humans are in the room.
1 sec.
High
Sensor output
Low
Human motion
(Condition of 10 times or more output)
Detection signal ON
from the sensor OFF
3 sec. If the detection signal (ON) continues 3 sec. or more,

it judges humans are in the room.
Human detection ON
signal OFF (R21086)
The sensor detects human motion by receiving infrared rays and displays the pulse wave
output.
The microcomputer in the indoor unit carries out a sampling every 20 msec. and if it detects
10 cycles of the wave in one second in total, and when the ON signal continues 3 sec., it
judges human is in the room as the motion signal is ON.
2-area INTELLIGENT EYE sensor is divided into 2 areas and detects humans in each area.
The sensor may detect human motion with up to 20 msec. latency.
Image of 2-area INTELLIGENT EYE
Wall
Top view
Indoor unit
Area B Area A
A microcomputer judges human presence by

the sensor signal from each area A and B.
(R21087)

2. The motions (in cooling)

within within
20 min. 20 min. within
20 min. 20 min.
Human detection ON
signal OFF
↑ ↑ ↑
Reset Reset Reset
Target temperature
Remote controller ON
INTELLIGENT OFF
EYE button
Operation ON
OFF
Set speed Set speed
Fan speed (+)
OFF
(R19414)
In FAN operation, the fan speed is reduced by 60 rpm.

When the microcomputer does not have a signal from the sensor in 20 minutes, it judges
that nobody is in the room and operates the unit at a temperature shifted from the target
temperature. (cooling / dry: 1 ~ 2°C higher, heating: 2°C lower, automatic: according to the
operation mode at that time.)
3. Airflow direction in 2-area INTELLIGENT EYE operation

Detection method: The opposite area of detected area is set as the target direction.
Wall
Top view
Indoor unit
Left Right
Human
Area B Area A
(R3853)
1. Detection signal ON in both area A and B: Shift the airflow direction to area B (left side)
2. Detection signal ON in area A: Shift the airflow direction to area B (left side)
3. Detection signal ON in area B: Shift the airflow direction to area A (right side)
4. Detection signal OFF in both area A and B: No change
*When the detection signal is OFF for 20 minutes in both area A and B, the unit starts energy
saving operation.
Note: For dry operation, the temperature cannot be set with a remote controller, but the target
temperature is shifted internally.

1.12 Inverter POWERFUL Operation

Outline In order to exploit the cooling and heating capacity to full extent, the air conditioner can be
operated by increasing the indoor fan rotating speed and the compressor frequency.
Detail When the POWERFUL button is pressed, the fan speed and target temperature are converted
to the following states for 20 minutes.
Operation mode Fan speed Target temperature
COOL H tap + A rpm 18°C
DRY Dry rotating speed + A rpm Lowered by 2.5°C
HEAT H tap + A rpm 31°C
FAN H tap + A rpm —
AUTO Same as cooling / heating in The target temperature is
POWERFUL operation kept unchanged.
A = 60 ~ 80 rpm (depending on the model)
Ex: POWERFUL operation in cooling
Target temp. It should be the lower limit of

cooling temperature.
18˚C
POWERFUL It counts 20 minutes also

ON in the remote controller.
POWERFUL
OFF
Fan Ending condition:
A rpm 1. After the lapse of 20 minutes.
H tap 2. Operation OFF
20 minutes 3. POWERFUL operation is OFF.
Set tap
(R19177)
Note: POWERFUL operation cannot be used together with ECONO, COMFORT AIRFLOW, or
OUTDOOR UNIT QUIET operation.

1.13 Clock Setting

ARC466 Series The clock can be set by taking the following steps:
1. Press the Clock button.
→ is displayed and MON and blink.
2. Press the Select or button to set the clock to the current day of the week.
3. Press the Clock button.
→ blinks.
4. Press the Select or button to adjust the clock to the present time.
Holding down the Select or button increases or decreases the time display rapidly.
5. Press the Clock button to set the clock. (Point the remote controller at the indoor unit when
pressing the button.)
→ blinks and clock setting is completed.
0:00
Select
button
Clock
button
(R19926)

1.14 WEEKLY TIMER Operation

Outline Up to 4 timer settings can be saved for each day of the week (up to 28 settings in total).
The 3 items: ON/OFF, temperature, and time can be set.
Detail
Setting example of the WEEKLY TIMER

The same timer settings are used from Monday through Friday, while different timer settings are used for the weekend.
[Monday] Make timer settings for programmes 1-4.

Programme 1 Programme 2 Programme 3 Programme 4
ON OFF ON OFF
25˚C 27˚C
6:00 8:30 17:30 22:00
ON OFF ON OFF
[Tuesday] Use the copy mode to make settings for Tuesday to Friday, because these settings are the same as
to those for Monday.
[Friday]
ON OFF ON OFF
25˚C 27˚C
6:00 8:30 17:30 22:00
[Saturday] No timer settings
[Sunday] Make timer settings for programmes 1-4.

ON OFF OFF ON
25˚C 27˚C 27˚C
8:00 10:00 19:00 21:00
ON OFF OFF ON
• Up to 4 reservations per day and 28 reservations per week can be set using the WEEKLY TIMER. The effective use of the
copy mode simplifies timer programming.
• The use of ON-ON-ON-ON settings, for example, makes it possible to schedule operating mode and set temperature
changes. Furthermore, by using OFF-OFF-OFF-OFF settings, only the turn off time of each day can be set. This will turn
off the air conditioner automatically if you forget to turn it off.

To use WEEKLY TIMER operation

Setting mode
• Make sure the day of the week and time are set. If not, set the day of the week and time.

ON OFF ON OFF
[Monday] 25˚C 27˚C

6:00 8:30 17:30 22:00
Setting Displays
Day and number ON/OFF Time Temperature
1. Press .
• The day of the week and the reservation number of the current day will be displayed.
• 1 to 4 settings can be made per day.
2. Press to select the desired day of the week

and reservation number.
• Pressing changes the reservation number and the day of the week.
3. Press .
• The day of the week and reservation number will be set.
•“ ” and “ ON ” blink.
4. Press to select the desired mode.

• Pressing changes the “ ON ” or “ OFF ” setting in sequence.
blank
ON TIMER OFF TIMER No Setting
• In case the reservation has already been set, selecting “blank” deletes the
reservation.
• Proceed to step 9 if “blank” is selected.
• To return to the day of the week and reservation number setting, press .
5. Press .
• The ON/OFF TIMER mode will be set.
•“ ” and the time blink.

6. Press to select the desired time.

• The time can be set between 0:00 and 23:50 in 10-minute intervals.
• To return to the ON/OFF TIMER mode setting, press .
• Proceed to step 9 when setting the OFF TIMER.
7. Press .
• The time will be set.
•“ ” and the temperature blink.
8. Press to select the desired temperature.

• The temperature can be set between 10˚C and 32˚C.
COOL or AUTO: The unit operates at 18˚C even if it is set to 10 to 17˚C.
HEAT or AUTO: The unit operates at 30˚C even if it is set to 31 to 32˚C.
• To return to the time setting, press .
• The set temperature is only displayed when the mode setting is on.
9. Press .
• The temperature will be set and go to the next reservation setting.
• The temperature is set while in ON TIMER operation, and the time is set while in OFF
TIMER operation.
• The next reservation screen will appear.
• To continue further settings, repeat the procedure from step 4.
10. Press to complete the setting.

• Be sure to direct the remote controller toward the indoor unit and check for a receiving
tone and blinking of the OPERATION lamp.
•“ ” is displayed on the LCD and WEEKLY TIMER operation is activated.
• The TIMER lamp lights orange.
Display
• A reservation made once can be easily copied and the same settings used for another
day of the week. Refer to Copy mode .
NOTE
Notes on WEEKLY TIMER operation
• Do not forget to set the clock on the remote controller first.
• The day of the week, ON/OFF TIMER mode, time and set temperature (only for ON TIMER mode) can be set with the WEEKLY TIMER.
Other settings for the ON TIMER are based on the settings just before the operation.
• WEEKLY TIMER and ON/OFF TIMER operation cannot be used at the same time. The ON/OFF TIMER operation has priority if it is set while
WEEKLY TIMER is still active. The WEEKLY TIMER will enter the standby state, and “ ” will disappear from the LCD. When the
ON/OFF TIMER is up, the WEEKLY TIMER will automatically become active.
• Only the time and set temperature with the WEEKLY TIMER are sent with the . Set the WEEKLY TIMER only after setting the operation
mode, the airflow rate and the airflow direction ahead of time.
• Turning off the circuit breaker, power failure, and other similar events will render operation of the indoor unit’s internal clock inaccurate. Reset the clock.
• can be used only for the time and temperature settings. It cannot be used to go back to the reservation number.

Copy mode
• A reservation made once can be copied to another day of the week. The whole reservation of
the selected day of the week will be copied.

ON OFF ON OFF
[Monday] 25˚C 27˚C
6:00 8:30 17:30 22:00
COPY

ON OFF ON OFF
[Tuesday]
to 25˚C 27˚C
[Friday] 6:00 8:30 17:30 22:00
Setting Displays
Confirmation Copy Paste Normal
1. Press .
2. Press to confirm the day of the week to be copied.
3. Press .
• The whole reservation of the selected day of the week will be copied.
4. Press to select the destination day of the week.
5. Press .
• The reservation will be copied to the selected day of the week. The whole reservation of
the selected day of the week will be copied.
• To continue copying the settings to other days of the week, repeat step 4 and step 5.
6. Press to complete the setting.

NOTE
Note on copy mode
• The entire reservation of the source day of the week is copied in the copy mode.
In the case of making a reservation change for any day of the week individually after copying the content of weekly reservations, press
and change the settings in the steps of Setting mode .

Confirming a reservation
• The reservation can be confirmed.
Setting Displays
Normal Confirmation
1. Press .
• The day of the week and the reservation number of the current day will be displayed.
2. Press to select the day of the week and the

reservation number to be confirmed.
• Pressing displays the reservation details.
• To change the confirmed reserved settings, select the reservation number and press
• The mode is switched to setting mode. Proceed to setting mode step 2.
3. Press to exit the confirmation mode.

• The TIMER lamp lights orange.
Display
To deactivate WEEKLY TIMER operation
Press while “ ” is displayed on

the LCD.
• The “ ” will disappear from the LCD.
• The TIMER lamp goes off.
• To reactivate the WEEKLY TIMER operation, press again.
• If a reservation deactivated with is activated once again, the last reservation
mode will be used.
NOTE
• If not all the reservation settings are reflected, deactivate the WEEKLY TIMER operation once.Then press again to
reactivate the WEEKLY TIMER operation.

To delete reservations
An individual reservation
1. Press .
• The day of the week and the reservation number will be displayed.
2. Press to select the day of the week and

the reservation number to be deleted.
3. Press .
•“ ” and “ ” or “ ” blink.
4. Press until no icon is displayed.

• Pressing changes the ON/OFF TIMER mode in sequence.
• Selecting “ blank ” will cancel any reservation you may have.

blank
ON TIMER OFF TIMER No Setting
5. Press .
• The selected reservation will be deleted.
6. Press .
• If there are still other reservations, WEEKLY TIMER operation will be activated.
Reservations for each day of the week

• This function can be used for deleting reservations for each day of the week.
• It can be used while confirming or setting reservations.
1. Press to select the day of the week to be

deleted.
2. Hold for about 5 seconds.
• The reservation of the selected day of the week will be deleted.
All reservations
Hold for about 5 seconds with the normal display.

• Be sure to direct the remote controller toward the indoor unit and check for a receiving tone.
• This operation cannot be used for the WEEKLY TIMER setting display.
• All reservations will be deleted.

1.15 Other Functions

1.15.1 Hot-Start Function
In order to prevent the cold air blast that normally occurs when heating operation is started, the
temperature of the indoor heat exchanger is detected, and the airflow is either stopped or
significantly weakened resulting in comfortable heating.
Note: The cold air blast is prevented using similar control when defrost control starts or when the
thermostat is turned ON.
1.15.2 Signal Receiving Sign

When the indoor unit receives a signal from the remote controller, the unit emits a signal
receiving sound.
1.15.3 Indoor Unit ON/OFF Button

An ON/OFF button is provided on the display of the unit.
Press the ON/OFF button once to start operation. Press once again to stop it.
The ON/OFF button is useful when the remote controller is missing or the battery has run
out.
The operation mode refers to the following table.
Operation mode Temperature setting Airflow rate
AUTO 25ºC Automatic
Ex. 35/42/50 class
ON/OFF button (R21335)
<Forced cooling operation>

Forced cooling operation can be started by pressing the ON/OFF button for 5 ~ 9 seconds while
the unit is not operating.
Refer to page 110 for detail.
Note: When the ON/OFF button is pressed for 10 seconds or more, the forced cooling operation is
stopped.
1.15.4 Auto-restart Function

If a power failure (including one for just a moment) occurs during the operation, the operation
restarts automatically when the power is restored in the same condition as before the power
failure.
Note: It takes 3 minutes to restart the operation because the 3-minute standby function is activated.

Function of Thermistor SiBE041434E
2. Function of Thermistor
Electronic
expansion valve
(1) (3)
Four way valve
(2) Compressor (R14247)
(1) Outdoor Heat 1. The outdoor heat exchanger thermistor is used for controlling the target discharge pipe
Exchanger temperature. The system sets the target discharge pipe temperature according to the
Thermistor outdoor and indoor heat exchanger temperature, and controls the electronic expansion valve
opening so that the target discharge pipe temperature can be obtained.
2. In cooling operation, the outdoor heat exchanger thermistor is used for detecting the
disconnection of the discharge pipe thermistor. When the discharge pipe temperature drops
below the outdoor heat exchanger temperature by more than a certain value, the discharge
pipe thermistor is judged as disconnected.
3. In cooling operation, the outdoor heat exchanger thermistor is used for high pressure
protection.
(2) Discharge 1. The discharge pipe thermistor is used for controlling discharge pipe temperature. If the
Pipe Thermistor discharge pipe temperature (used in place of the inner temperature of the compressor) rises
abnormally, the operating frequency becomes lower or the operation halts.
2. The discharge pipe thermistor is used for detecting disconnection of the discharge pipe
thermistor.
(3) Indoor Heat 1. The indoor heat exchanger thermistor is used for controlling the target discharge pipe
Exchanger temperature. The system sets the target discharge pipe temperature according to the
Thermistor outdoor and indoor heat exchanger temperature, and controls the electronic expansion valve
opening so that the target discharge pipe temperature can be obtained.
2. In cooling operation, the indoor heat exchanger thermistor is used for freeze-up protection
control. If the indoor heat exchanger temperature drops abnormally, the operating frequency
becomes lower or the operation halts.
3. In heating operation, the indoor heat exchanger thermistor is used for detecting the
disconnection of the discharge pipe thermistor. When the discharge pipe temperature drops
below the indoor heat exchanger temperature by more than a certain value, the discharge
pipe thermistor is judged as disconnected.

SiBE041434E Control Specification
3. Control Specification
3.1 Mode Hierarchy
Outline The air conditioner control has normal operation mode, forced operation mode, and power
transistor test mode for installation and servicing.
Detail
Air conditioner control mode

Forced operation mode
Forced cooling operation (for pump down operation)
Power transistor test mode
Normal operation mode
Fan
Cooling (includes drying)
Heating
Heating
Defrosting
Stop (indoor unit: OFF)
Preheating operation
Discharging from capacitor
Stop
(R19522)
Note: Unless specified otherwise, a dry operation command is regarded as cooling operation.
3.2 Frequency Control

Outline The compressor frequency is determined according to the difference between the room
thermistor temperature and the target temperature.
When the shift of the frequency is less than zero (∆F<0) by PI control,
the target frequency is used as the command frequency.
Dropping function
Input current control, etc.
Upper limit frequency Upper limit function

FMAX Compressor protection function
Command frequency Limit frequency Skip control Target frequency
Initial frequency Lower limit frequency Lower limit function

PI control FMIN Four way valve operation compensation, etc.
Defrost control
(R18023)

Control Specification SiBE041434E
Detail 1. Determine command frequency

Command frequency is determined in the following order of priority.
1. Limiting defrost control time
2. Forced cooling
3. Indoor frequency command
2. Determine upper limit frequency

The minimum value is set as an upper limit frequency among the frequency upper limits of
the following functions:
Compressor protection, input current, discharge pipe temperature, heating peak-cut, freeze-
up protection, defrost.
3. Determine lower limit frequency

The maximum value is set as a lower limit frequency among the frequency lower limits of the
following functions:
Four way valve operation compensation, draft prevention, pressure difference upkeep.
4. Determine prohibited frequency

There is a certain prohibited frequency such as a power supply frequency.
Initial Frequency When starting the compressor, the frequency is initialized according to the ∆D value of the
indoor unit.
<∆D signal: Indoor Frequency Command>

The difference between the room thermistor temperature and the target temperature is taken as
the ∆D signal and is used for frequency command.
Temperature ∆D Temperature ∆D Temperature ∆D Temperature ∆D
difference signal difference signal difference signal difference signal
–2.0 ∗OFF 0 4 2.0 8 4.0 C
–1.5 1 0.5 5 2.5 9 4.5 D
–1.0 2 1.0 6 3.0 A 5.0 E
–0.5 3 1.5 7 3.5 B 5.5 F
∗OFF = Thermostat OFF
PI Control 1. P control
The ∆D value is calculated in each sampling time (20 seconds), and the frequency is
adjusted according to its difference from the frequency previously calculated.
2. I control
If the operating frequency does not change for more than a certain fixed time, the frequency
is adjusted according to the ∆D value.
When the ∆D value is low, the frequency is lowered.
When the ∆D value is high, the frequency is increased.
3. Frequency control when other controls are functioning

When frequency is dropping;
Frequency control is carried out only when the frequency drops.
For controlling lower limit;
Frequency control is carried out only when the frequency rises.
4. Upper and lower limit of frequency by PI control

The frequency upper and lower limits are set according to the command of the indoor unit.
When the indoor or outdoor unit quiet operation command comes from the indoor unit, the
upper limit frequency is lower than the usual setting.

3.3 Controls at Mode Changing / Start-up

3.3.1 Preheating Control
Outline The inverter operation in open phase starts with the conditions of the preheating command from
the indoor unit, the outdoor temperature, the discharge pipe temperature, and the radiation fin
temperature.
Detail Outdoor temperature ≥ A°C → Control I

Outdoor temperature < A°C → Control II
Control I
ON condition
Discharge pipe temperature < B°C
Radiation fin temperature <85°C
OFF condition
Discharge pipe temperature > C°C
Radiation fin temperature ≥ 90°C
Control II
ON condition
Discharge pipe temperature < D°C
Radiation fin temperature <85°C
OFF condition
Discharge pipe temperature > E°C
Radiation fin temperature ≥ 90°C
A (°C) B (°C) C (°C) D (°C) E (°C)

–2.5 0 2 10 12
3.3.2 Four Way Valve Switching

Outline The four way valve coil is energized / not energized depending on the operation. (Heating: ON,
Cooling / Dry / Defrost: OFF) In order to eliminate the switching sound as the four way valve coil
switches from ON to OFF when the heating is stopped, the OFF delay switch of the four way
valve is carried out.
Detail OFF delay switch of four way valve

The four way valve coil is energized for 160 seconds after the operation is stopped.

3.3.3 Four Way Valve Operation Compensation

Outline At the beginning of operation as the four way valve is switched, the pressure difference to
activate the four way valve is acquired when the output frequency is higher than a certain fixed
frequency, for a certain fixed time.
Detail Starting Conditions

1. When the compressor starts and the four way valve switches from OFF to ON
2. When the four way valve switches from ON to OFF during operation
3. When the compressor starts after resetting
4. When the compressor starts after the fault of four way valve switching
The lower limit of frequency keeps A Hz for B seconds with any conditions 1 through 4 above.
20/25/35 class 42/50 class

A (Hz) 68 66 52
B (seconds) 45 60
3.3.4 3-minute Standby

Turning on the compressor is prohibited for 3 minutes after turning it off.
(The function is not activated when defrosting.)
3.3.5 Compressor Protection Function

When turning the compressor from OFF to ON, the upper limit of frequency is set as follows.
(The function is not activated when defrosting.)
(Hz)
Frequency
C
B
A
(sec.)
D E F Time
(R13528)
20/25/35 class 42/50 class

A (Hz) 26 62
B (Hz) 66 80
C (Hz) 72 98
D (seconds) 15 120
E (seconds) 180 600
F (seconds) 180 60

3.4 Discharge Pipe Temperature Control

Outline The discharge pipe temperature is used as the internal temperature of the compressor. If the
discharge pipe temperature rises above a certain level, the upper limit of frequency is set to
keep the discharge pipe temperature from rising further.
Detail
Stop zone
A˚C
B˚C
Dropping zone
C˚C
Keep zone
D˚C
Up zone
E˚C
Reset zone
Discharge pipe
(R14642)
temperature
20/25/35/42/50 class
A (°C) 118
B (°C) 108
C (°C) 103
D (°C) 97
E (°C) 85
Zone Control
Stop zone When the temperature reaches the stop zone, the compressor stops.
Dropping zone The upper limit of frequency decreases.
Keep zone The upper limit of frequency is kept.
Up zone The upper limit of frequency increases.
Reset zone The upper limit of frequency is canceled.

3.5 Input Current Control

Outline The microcomputer calculates the input current while the compressor is running, and sets the
frequency upper limit based on the input current.
In case of heat pump models, this control is the upper limit control of frequency and takes
priority over the lower limit control of four way valve operation compensation.
Detail
Compressor Stop
(A)
Stop Zone
A
Dropping Zone
Keep Zone
C
Input current Reset Zone
(R14643)
Frequency control in each zone

Stop zone
After 2.5 seconds in this zone, the compressor is stopped.
Dropping zone
The upper limit of the compressor frequency is defined as operation frequency – 2 Hz.
After this, the output frequency is lowered by 2 Hz every second until it reaches the keep
zone.
Keep zone
The present maximum frequency goes on.
Reset zone
Limit of the frequency is canceled.
20/25 class 35 class 42/50 class

Cooling Heating Cooling Heating Cooling Heating
A (A) 9.25 9.25 10.0
B (A) 6.25 7.5 8.25 8.5
C (A) 5.5 6.75 7.5 7.5
Limitation of current dropping and stop value according to the outdoor temperature
The current drops when outdoor temperature becomes higher than a certain level
(depending on the model).

3.6 Freeze-up Protection Control

During cooling operation, the signal sent from the indoor unit determines the frequency upper
limit and prevents freezing of the indoor heat exchanger. (The signal from the indoor unit is
divided into zones.)
The operating frequency limitation is judged with the indoor heat exchanger temperature.
Indoor heat exchanger
thermistor temperature
13˚C
Reset zone
A˚C
Up zone
B˚C
Keep zone
C˚C
Dropping zone
0˚C
Stop zone
(R14718)
A (°C) B (°C) C (°C)

20/25 class 11 9 7
35/42/50 class 9.5 7.5 5.5
3.7 Heating Peak-cut Control

During heating operation, the indoor heat exchanger temperature determines the frequency
upper limit to prevent abnormal high pressure.
The operating frequency limitation is judged with the indoor heat exchanger temperature.
Stop zone
A˚C
B˚C
Dropping zone
C˚C
Keep zone
D˚C
Up zone
E˚C
Indoor heat exchanger Reset zone
thermistor temperature
(R14645)
20/25/35 class 42/50 class

A (°C) 58 53
B (°C) 52 50
C (°C) 49 47
D (°C) 47 45
E (°C) 44.5 42.5
Zone Control
Stop zone When the temperature reaches the stop zone, the compressor stops.
Dropping zone The upper limit of frequency decreases.
Keep zone The upper limit of frequency is kept.
Up zone The upper limit of frequency increases.
Reset zone The upper limit of frequency is canceled.

3.8 Outdoor Fan Control

1. Fan ON control to cool down the electrical box
The outdoor fan is turned ON when the electrical box temperature is high while the compressor
is OFF.
2. Fan OFF control during defrosting

The outdoor fan is turned OFF during defrosting.
3. Fan OFF delay when stopped

The outdoor fan is turned OFF 60 ~ 70 seconds after the compressor stops.
4. Fan speed control for pressure difference upkeep

The rotation speed of the outdoor fan is controlled for keeping the pressure difference during
cooling operation with low outdoor temperature.
When the pressure difference is low, the rotation speed of the outdoor fan is reduced.
When the pressure difference is high, the rotation speed of the outdoor fan is controlled as
well as normal operation.
5. Fan speed control during forced cooling operation

The outdoor fan is controlled as well as normal operation during forced cooling operation.
6. Fan speed control during POWERFUL operation

The rotation speed of the outdoor fan is increased during POWERFUL operation.
7. Fan speed control during indoor / outdoor unit quiet operation

The rotation speed of the outdoor fan is reduced by the command of the indoor / outdoor unit
quiet operation.
8. Fan ON/OFF control when operation (cooling, heating, dry) starts / stops
The outdoor fan is turned ON when the operation starts. The outdoor fan is turned OFF when
the operation stops.
3.9 Liquid Compression Protection Function

Outline In order to increase the dependability of the compressor, the compressor is stopped according
to the outdoor temperature and temperature of the outdoor heat exchanger.
Detail Operation stops depending on the outdoor temperature.

Compressor turns off under the conditions that the system is in cooling operation and outdoor
temperature is below –12°C.

3.10 Defrost Control

Outline Defrosting is carried out by the cooling cycle (reverse cycle). The defrosting time or outdoor
heat exchanger temperature must be more than a certain value to finish defrosting.
Detail Conditions for Starting Defrost

The starting conditions are determined with the outdoor temperature and the outdoor heat
exchanger temperature.
The system is in heating operation.
The compressor operates for 6 minutes.
More than A minutes (depending on the duration of the previous defrost control) of
accumulated time have passed since the start of the operation, or ending the previous
defrosting.
Conditions for Canceling Defrost

The judgment is made with the outdoor heat exchanger temperature. (B°C)
D Hz
C Hz
PI control
Frequency
0 Hz 0 Hz
F sec.
E sec. G sec. H sec.
ON
Compressor
OFF
ON
Four way valve
OFF
5 ~ 8 sec. 5 ~ 8 sec.
ON
Fan
OFF
Electronic
expansion valve
opening Normal J pulse K pulse zone L pulse Starting
control zone zone control
(R21278)
20/25/35 class 42/50 class

A (minutes) 28 20 ~ 25
B (°C) 4 ~ 18 6 ~ 30
C (Hz) 56 64
D (Hz) 56 72
E (seconds) 30 40
F (seconds) 60 210
G (seconds) 480 450
H (seconds) 80 90
J (pulse) 450 400
K (pulse) 200 ~ 280 350 ~ 400
L (pulse) 200 400
: The same value continues.

3.11 Electronic Expansion Valve Control

Outline The following items are included in the electronic expansion valve control.
Electronic expansion valve is fully closed
1. Electronic expansion valve is fully closed when turning on the power.
2. Pressure equalizing control
Open Control
1. Electronic expansion valve control when starting operation
2. Electronic expansion valve control when the frequency changes
3. Electronic expansion valve control for defrosting
4. Electronic expansion valve control when the discharge pipe temperature is abnormally high
5. Electronic expansion valve control when the discharge pipe thermistor is disconnected
Feedback Control
Target discharge pipe temperature control
Detail The followings are the examples of electronic expansion valve control which function in each
operation mode.
Frequency change under discharge pipe thermistor

During target discharge pipe temperature control
Frequency change under target discharge pipe

Frequency change under starting control
Discharge pipe thermistor disconnection

Status
Power on ; Compressor stop
During defrost control

disconnection control
temperature control
Control
Operation start
Starting operation control
Control when the frequency changes
Target discharge pipe temperature control
Discharge pipe thermistor disconnection control
High discharge pipe temperature control
Defrost control (heating only)
Pressure equalizing control
Opening limit control
: Available
: Not available

3.11.1 Fully Closing with Power ON

The electronic expansion valve is initialized when turning on the power. The opening position is
set and the pressure is equalized.
3.11.2 Pressure Equalizing Control

When the compressor is stopped, the pressure equalizing control is activated. The electronic
expansion valve opens and the pressure is equalized.
3.11.3 Opening Limit Control

The maximum and minimum opening of the electronic expansion valve are limited.
20/25/35 class 42/50 class
Maximum opening (pulse) 480 500
Minimum opening (pulse) 32 52
The electronic expansion valve is fully closed when cooling operation stops, and is opened at a
fixed degree during defrosting.
3.11.4 Starting Operation Control

The electronic expansion valve opening is controlled when the operation starts, thus preventing
superheating or liquid compression.
3.11.5 Control when the Frequency Changes

When the target discharge pipe temperature control is active, if the target frequency changes to
a specified value in a certain time period, the target discharge pipe temperature control is
canceled and the target opening of the electronic expansion valve is changed according to the
frequency shift.
3.11.6 High Discharge Pipe Temperature Control

When the compressor is operating, if the discharge pipe temperature exceeds a certain value,
the electronic expansion valve opens and the refrigerant runs to the low pressure side. This
procedure lowers the discharge pipe temperature.

3.11.7 Discharge Pipe Thermistor Disconnection Control

Outline The disconnection of the discharge pipe thermistor is detected by comparing the discharge pipe
temperature with the condensation temperature. If the discharge pipe thermistor is
disconnected, the electronic expansion valve opens according to the outdoor temperature and
the operation frequency, operates for a specified time, and then stops.
After 3 minutes, the operation restarts and checks if the discharge pipe thermistor is
disconnected. If the discharge pipe thermistor is disconnected, the system stops after operating
for a specified time.
If the disconnection is detected repeatedly, the system is shut down. When the compressor runs
for 60 minutes without any error, the error counter is reset.
Detail Determining thermistor disconnection

When the starting control (cooling: A seconds, heating: B seconds) finishes, the detection timer
for disconnection of the discharge pipe thermistor (C seconds) starts. When the timer is over,
the following adjustment is made.
1. When the operation mode is cooling
When the following condition is fulfilled, the discharge pipe thermistor disconnection is
ascertained.
Discharge pipe temperature + 6°C < outdoor heat exchanger temperature
2. When the operation mode is heating
When the following condition is fulfilled, the discharge pipe thermistor disconnection is
ascertained.
Discharge pipe temperature + 6°C < indoor heat exchanger temperature
20/25/35 class 42/50 class

A (seconds) 10 10
B (seconds) 120 30
C (seconds) 810 720
When the thermistor is disconnected

When the disconnection is ascertained, the compressor continues operation for 9 minutes and
then stops.
If the compressor stops repeatedly, the system is shut down.
3.11.8 Target Discharge Pipe Temperature Control

The target discharge pipe temperature is obtained from the indoor and outdoor heat exchanger
temperature, and the electronic expansion valve opening is adjusted so that the actual
discharge pipe temperature becomes close to the target discharge pipe temperature. (Indirect
SH (superheating) control using the discharge pipe temperature)
The target discharge pipe

SC temperature is set as to become
(Subcool)
the aim SH.
The inclination does not change
depending on the operating condition.
SH
(Superheat)
(R18921)
The electronic expansion valve opening and the target discharge pipe temperature are checked
every 20 seconds. The opening degree of the electronic expansion valve is adjusted by the
followings.
Target discharge pipe temperature
Actual discharge pipe temperature
Previous discharge pipe temperature

3.12 Malfunctions
3.12.1 Sensor Malfunction Detection
Sensor malfunction can be detected in the following thermistors:
1. Outdoor heat exchanger thermistor
2. Discharge pipe thermistor
3. Radiation fin thermistor
4. Outdoor temperature thermistor
3.12.2 Detection of Overcurrent and Overload

Outline An excessive output current is detected and the OL temperature is observed to protect the
compressor.
Detail If the OL (compressor head) temperature exceeds 120°C, the system shuts down the
compressor.
If the inverter current exceeds 9.25 ~ 10 A (depending on the model), the system shuts down
the compressor.
3.12.3 Refrigerant Shortage Detection

Detecting by power consumption
If the power consumption is below the specified value and the frequency is higher than the
specified frequency, it is regarded as refrigerant shortage.
The power consumption is low comparing with that in the normal operation when refrigerant is
insufficient, and refrigerant shortage is detected by checking power consumption.
Refrigerant shortage zone

Power consumption
(Input current)
50 ~ 55 Hz Frequency
(depending on
the model) (R21198)
Refer to page 69 for detail.

SiBE041434E
Part 5
Remote Controller
1. 20/25 Class ...........................................................................................52
2. 35/42/50 Class ......................................................................................54
51 Remote Controller
SiBE041434E 20/25 Class
1. 20/25 Class
Signal transmitter
Display (LCD)
Receiver • Displays the current settings.
(In this illustration, each section is
shown with all its displays on for the
purpose of explanation.)
• To use the remote controller, aim the
transmitter at the indoor unit. If there
is anything to block signals between
the unit and the remote controller,
such as a curtain, the unit will not
operate. Temperature adjustment
• The maximum distance for
communication is about 7m.
buttons
• Changes the temperature setting.
FAN setting button : AUTO 18 ~ 30 °C

• Selects the airflow rate setting. : DRY Not available
: COOL 18 ~ 32 °C
: HEAT 10 ~ 30 °C
Auto Indoor unit quiet Low
: FAN Not available
Middle low
On/Off button
• Press this button once to start
operation.
Press once again to stop it.
High Middle high Middle
• In indoor unit quiet operation,

operation sound becomes weak.
(The airflow rate also decreases.)
• In DRY operation, the airflow rate Powerful1 button
setting is not available. • Starts POWERFUL operation.
(R21337)
< ARC466A6 >
Reference Refer to the following pages for detail.

1 POWERFUL operation P.28
Note: Refer to the operation manual of applicable model for detail. You can download operation
manuals from Daikin Business Portal:
Daikin Business Portal → Product Information → Operation/Installation Manual
(URL: https://global1d.daikin.com/business_portal/login/)
Remote Controller 52
20/25 Class SiBE041434E
Open the Front Cover
Mode button
• Selects the operation mode.
AUTO DRY COOL HEAT FAN
Econo3 button
• ECONO operation.
Quiet button
• OUTDOOR UNIT QUIET Swing4 button
operation.
• Adjusts the airflow direction.
• OUTDOOR UNIT QUIET
• When you press the Swing
operation is not available in
button, the flap moves up and
FAN and DRY operation.
down. The flap stops when
you press the Swing button
operation and POWERFUL
again.
operation cannot be used at
the same time. Priority is
given to the function you Sensor button
pressed last. (INTELLIGENT EYE
operation5)
Comfort2 button • To start INTELLIGENT EYE
• The airflow direction will be operation, press the Sensor
in upward while in COOL button.
operation, in downward while " " is displayed on the LCD.
in HEAT operation. This • To cancel the INTELLIGENT
function will prevent cold or EYE operation, press the
warm air from directly Sensor button again.
blowing on your body. " " disappears from the LCD.
Weekly
: Weekly button
Off timer button
• Press this button and adjust : Program button
the day and time with the Copy
Select button. : Copy button
Press this button again to Back
complete TIMER setting. : Back button
Select button Next
: Next button
• Changes the ON/OFF
Timer cancel button TIMER and WEEKLY • WEEKLY TIMER6 operation.
• Cancels the timer setting. TIMER settings.
• It cannot be used for the
WEEKLY TIMER operation.
On Timer button
• Press this button and adjust
Clock7 button the day and time with the
Select button.
Press this button again to
complete TIMER setting.
(R21338)

2 COMFORT AIRFLOW operation P.19, 20 5 INTELLIGENT EYE operation P.25
3 ECONO operation P.24 6 WEEKLY TIMER operation P.30
4 Auto-swing setting P.18 7 Clock setting P.29
SiBE041434E 35/42/50 Class
2. 35/42/50 Class
Signal transmitter
Display (LCD)
• Displays the current settings.
Receiver (In this illustration, each section is
shown with all its displays on for the
• To use the remote controller, aim the purpose of explanation.)
transmitter at the indoor unit. If there
is anything to block signals between
the unit and the remote controller,
such as a curtain, the unit will not
operate.
• The maximum distance for Temperature adjustment
communication is about 7 m. button
• Changes the temperature setting.
Fan setting button : AUTO 18 ~ 30 °C
• Selects the airflow rate setting. : DRY Not available
: COOL 18 ~ 32 °C
Auto Indoor unit quiet Low : HEAT 10 ~ 30 °C

: FAN Not available
Middle low
On/Off button
• Press this button once to start
operation.
High Middle high Middle Press once again to stop it.
• In indoor unit quiet operation,
operation sound becomes weak.
(The airflow rate also decreases.)
• In DRY operation, the airflow rate Powerful1 button
setting is not available.
• Starts POWERFUL operation.
(R21336)
< ARC466A9 >

1 POWERFUL operation P.28
Remote Controller 54
35/42/50 Class SiBE041434E
Open the Front Cover

Mode button
• Selects the operation mode.
AUTO DRY COOL HEAT FAN
Econo4 / Quiet button

• Every time you press the
Econo/Quiet button, the
setting changes in the
following order.
Lamp brightness
setting button ECONO OUTDOOR UNIT
• Each time you press the QUIET
Brightness button, the
brightness of the indoor unit
blank
display changes to high, low,
or off. No setting Combination
operation is not available in
Comfort/Sensor button FAN and DRY operation.
(COMFORT AIRFLOW • OUTDOOR UNIT QUIET
Operation2/ INTELLIGENT operation and POWERFUL
EYE Operation3) operation cannot be used at
the same time. Priority is
• Every time you press the
given to the function you
Comfort/Sensor button, the pressed last.
setting changes in the
following order.
Swing5 buttons
• Adjusts the airflow direction.
COMFORT INTELLIGENT
• When you press the Swing
AIRFLOW EYE
button, the flap moves up and
down, or (and) the louver
moves right and left. The flap
blank (louver) stops when you press
No setting Combination the Swing button again.
Off Timer button : Weekly button

• Press this button and adjust Select button
the day and time with the • Changes the ON/OFF : Program button
Select button. TIMER and WEEKLY
Press this button again to : Copy button
TIMER settings.
: Back button
Timer cancel button Clock7 button : Next button
• Cancels the timer setting. • WEEKLY TIMER6 operation.

• It cannot be used for the On Timer button
WEEKLY TIMER operation. • Press this button and adjust
the day and time with the
Select button.
Press this button again to
(R19929)

2 COMFORT AIRFLOW operation P.19, 20 5 Auto-swing setting P.18
3 2-area INTELLIGENT EYE operation P.26 6 WEEKLY TIMER operation P.30
4 ECONO operation P.24 7 Clock setting P.29
SiBE041434E
Part 6
Service Diagnosis
1. General Problem Symptoms and Check Items .....................................57
2. Troubleshooting with LED .....................................................................58
2.1 Indoor Unit..............................................................................................58
2.2 Outdoor Unit ...........................................................................................58
3. Service Diagnosis .................................................................................59
4. Troubleshooting ....................................................................................62
4.1 Error Codes and Description ..................................................................62
4.2 Indoor Unit PCB Abnormality .................................................................63
4.3 Freeze-up Protection Control / Heating Peak-cut Control ......................64
4.4 Fan Motor (DC Motor) or Related Abnormality.......................................65
4.5 Thermistor or Related Abnormality (Indoor Unit)....................................68
4.6 Refrigerant Shortage ..............................................................................69
4.7 Low-voltage Detection or Over-voltage Detection..................................71
4.8 Signal Transmission Error (Between Indoor Unit and Outdoor Unit)......73
4.9 Unspecified Voltage (Between Indoor Unit and Outdoor Unit) ...............75
4.10 Outdoor Unit PCB Abnormality...............................................................76
4.11 OL Activation (Compressor Overload) ...................................................78
4.12 Compressor Lock ...................................................................................80
4.13 DC Fan Lock ..........................................................................................81
4.14 Input Overcurrent Detection ...................................................................82
4.15 Four Way Valve Abnormality..................................................................83
4.17 High Pressure Control in Cooling ...........................................................86
4.18 Compressor System Sensor Abnormality ..............................................87
4.19 Position Sensor Abnormality ..................................................................88
4.20 DC Voltage / Current Sensor Abnormality (20/25/35 Class Only)..........90
4.21 Thermistor or Related Abnormality (Outdoor Unit).................................91
4.22 Electrical Box Temperature Rise............................................................93
4.23 Radiation Fin Temperature Rise ............................................................94
4.24 Output Overcurrent Detection ................................................................95
5. Check ....................................................................................................97
5.1 Thermistor Resistance Check ................................................................97
5.2 Fan Motor Connector Output Check ......................................................98
5.3 Power Supply Waveforms Check...........................................................99
5.4 Electronic Expansion Valve Check.........................................................99
5.5 Four Way Valve Performance Check ...................................................100
5.6 Inverter Unit Refrigerant System Check...............................................100
5.7 Inverter Analyzer Check .......................................................................101
5.8 Rotation Pulse Check on the Outdoor Unit PCB ..................................102
5.9 Installation Condition Check.................................................................103
5.10 Discharge Pressure Check...................................................................104
5.11 Outdoor Fan System Check .................................................................104
5.12 Main Circuit Short Check......................................................................105
5.13 Power Module Check ...........................................................................106
Service Diagnosis 56
General Problem Symptoms and Check Items SiBE041434E
1. General Problem Symptoms and Check Items

Symptom Check Item Measures Reference
Page
The unit does not operate. Check the power supply. Check if the rated voltage is supplied. —
Check the type of the indoor unit. Check if the indoor unit type is compatible with —
the outdoor unit.
Check the outdoor temperature. Heating operation cannot be used when the
outdoor temperature is 24°CDB or higher, and —
cooling operation cannot be used when the
outdoor temperature is below –10°CDB.
Diagnose with remote controller — 62
indication.
Check the remote controller Check if address settings for the remote 112
addresses. controller and indoor unit are correct.
Operation sometimes Check the power supply. A power failure of 2 to 10 cycles stops air —
stops. conditioner operation. (Operation lamp OFF)
Check the outdoor temperature. Heating operation cannot be used when the
outdoor temperature is 24°CDB or higher, and —
cooling operation cannot be used when the
outdoor temperature is below –10°CDB.
indication.
The unit operates but does Check for wiring and piping errors in
not cool, or does not heat. the connection between the indoor — —
unit and outdoor unit.
Check for thermistor detection errors. Check if the thermistor is mounted securely. —
Check for faulty operation of the Set the unit to cooling operation, and check the
electronic expansion valve. temperature of the liquid pipe to see if the —
electronic expansion valve works.
indication.
Diagnose by service port pressure Check for refrigerant shortage. 69
and operating current.
Large operating noise and Check the output voltage of the — 106
vibrations power module.
Check the power module. — —
Check the installation condition. Check if the required spaces for installation
(specified in the installation manual) are —
provided.
57 Service Diagnosis
SiBE041434E Troubleshooting with LED
2. Troubleshooting with LED

2.1 Indoor Unit
Operation Lamp The operation lamp blinks when any of the following errors is detected.
1. When a protection device of the indoor or outdoor unit is activated, or when the thermistor
malfunctions.
2. When a signal transmission error occurs between the indoor and outdoor units.
In either case, conduct the diagnostic procedure described in the following pages.
Ex. 35/42/50 class
Operation
lamp
(green)
(R18419)
Service Monitor The indoor unit has one green LED (LED A) on the control PCB. When the microcomputer
works in order, the LED A blinks. (Refer to page 8, 10 for the location of LED A.)
2.2 Outdoor Unit

The outdoor unit has one green LED (LED A) on the PCB. When the microcomputer works in
order, the LED A blinks. (Refer to page 12, 14 for the location of LED A.)
Service Diagnosis SiBE041434E
3. Service Diagnosis
Method 1 1. When the timer cancel button is held down for 5 seconds, 00 is displayed on the temperature
display screen.
Timer cancel button
(R21282)
< ARC466 Series >
2. Press the timer cancel button repeatedly until a long beep sounds.
The code indication changes in the sequence shown below.
No. Code No. Code No. Code
1 00 13 C7 25 UA
2 U4 14 A3 26 UH
3 L5 15 H8 27 P4
4 E6 16 H9 28 L3
5 H6 17 C9 29 L4
6 H0 18 C4 30 H7
7 A6 19 C5 31 U2
8 E7 20 J3 32 EA
9 U0 21 J6 33 AH
10 F3 22 E5 34 FA
11 A5 23 A1 35 H1
12 F6 24 E1 36 P9
Note: 1. A short beep or two consecutive beeps indicate non-corresponding codes.

2. To return to the normal mode, hold the timer cancel button down for 5 seconds. When the
remote controller is left untouched for 60 seconds, it also returns to the normal mode.
3. Not all the error codes are displayed. When you cannot find the error code, try method 2.
(→ Refer to page 60.)
SiBE041434E Service Diagnosis
Method 2
1. Press the center of the Temp button and the Mode button at the same time.
(R11669)
5C is displayed on the LCD.
(R11821)
2. Select 5C (service check) with the Temp or Temp button.
3. Press the Mode button to enter the service check mode.
(R11672)
The left-side number blinks.
(R11670)
4. Press the Temp or Temp button and change the number until you hear the two
consecutive beeps or the long beep.
(R11671)
Service Diagnosis SiBE041434E
5. Diagnose by the sound.

beep: The left-side number does not correspond with the error code.
two consecutive beeps: The left-side number corresponds with the error code but the
right-side number does not.
long beep: Both the left-side and right-side numbers correspond with the error code.
(The numbers indicated when you hear the long beep are the error code.
→ Refer to page 62.)
6. Press the Mode button.
(R11672)
The right-side number blinks.
(R11673)
7. Press the Temp or Temp button and change the number until you hear the long beep.
(R11671)
8. Diagnose by the sound.

beep: The left-side number does not correspond with the error code.
two consecutive beeps: The left-side number corresponds with the error code but the
right-side number does not.
long beep: Both the left-side and right-side numbers correspond with the error code.
9. Determine the error code.

The numbers indicated when you hear the long beep are the error code.
Error codes and description → Refer to page 62.
10.Press the Mode button for 5 seconds to exit from the service check mode.
(When the remote controller is left untouched for 60 seconds, it returns to the normal mode
also.)
(R11672)
SiBE041434E Troubleshooting
4. Troubleshooting
4.1 Error Codes and Description
Reference
Error Codes Description Page
System 00 Normal —
U0 Refrigerant shortage 69
U2 Low-voltage detection or over-voltage detection 71
U4 Signal transmission error (between indoor unit and outdoor unit) 73
UA Unspecified voltage (between indoor unit and outdoor unit) 75
Indoor A1 Indoor unit PCB abnormality 63
Unit
A5 Freeze-up protection control / heating peak-cut control 64
A6 Fan motor (DC motor) or related abnormality 65
C4 Indoor heat exchanger thermistor or related abnormality 68
C9 Room temperature thermistor or related abnormality 68
Outdoor E1 Outdoor unit PCB abnormality 76
Unit
E5 OL activation (compressor overload) 78
E6 Compressor lock 80
E7 DC fan lock 81
E8 Input overcurrent detection 82
EA Four way valve abnormality 83
F3 Discharge pipe temperature control 85
F6 High pressure control in cooling 86
H0 Compressor system sensor abnormality 87
H6 Position sensor abnormality 88
H8 DC voltage / current sensor abnormality (20/25/35 class only) 90
H9 Outdoor temperature thermistor or related abnormality 91
J3 Discharge pipe thermistor or related abnormality 91
J6 Outdoor heat exchanger thermistor or related abnormality 91
L3 Electrical box temperature rise 93
L4 Radiation fin temperature rise 94
L5 Output overcurrent detection 95
P4 Radiation fin thermistor or related abnormality 91
: Displayed only when system-down occurs.
Troubleshooting SiBE041434E
4.2 Indoor Unit PCB Abnormality

Error Code A1
Method of Error The system checks if the circuit works properly within the microcomputer of the indoor unit.
Detection
Error Decision The system cannot set the internal settings.

Conditions
Supposed Wrong models interconnected

Causes Defective indoor unit PCB
Disconnection of connector
Reduction of power supply voltage
Troubleshooting
Be sure to turn off the power switch before connecting or disconnecting
Caution connectors, or parts may be damaged.
Check the combination of the

indoor and outdoor unit.
NO
OK? Match the compatible
models.
YES
Check the connection of ∗ To secure the connection,
connectors (See Note.). once disconnect the connector
and then reconnect it.
YES Check the power supply

OK?
voltage.
NO NO
Voltage as rated? Correct the power
supply.
YES
Start operation.
Correct the connection.
YES
Error repeats? Replace the indoor unit
PCB (control PCB).
NO
Completed.
YES Check the power supply

Error repeats? voltage.
NO NO
Voltage as rated? Correct the power
supply.
YES
Start operation.
YES
Error repeats? Replace the indoor unit
PCB (control PCB).
NO
Completed.
Completed.
(R20421)
Note: Check the following connector.

Model Type Connector
Wall mounted type Terminal board ~ Control PCB (H1, H2, H3)
4.3 Freeze-up Protection Control / Heating Peak-cut Control

Error Code A5
Method of Error Freeze-up protection control
Detection During cooling operation, the freeze-up protection control (operation halt) is activated
according to the temperature detected by the indoor heat exchanger thermistor.
Heating peak-cut control
During heating operation, the temperature detected by the indoor heat exchanger thermistor
is used for the heating peak-cut control (operation halt, outdoor fan stop, etc.).
Error Decision Freeze-up protection control

Conditions During cooling operation, the indoor heat exchanger temperature is below 0°C.
Heating peak-cut control
During heating operation, the indoor heat exchanger temperature is above 53 ~ 58°C
(depending on the model).
Supposed Short-circuited air

Causes Clogged air filter of the indoor unit
Dust accumulation on the indoor heat exchanger
Defective indoor heat exchanger thermistor
Defective indoor unit PCB
Troubleshooting
Check No.01
Check the air passage.
Refer to P.97
YES
Is there any short circuit? Provide sufficient air passage.
NO
Check the air filter.
YES
Dirty? Clean the air filter.
NO
Check the dust accumulation on
the indoor heat exchanger.
YES
Dirty? Clean the indoor heat
exchanger.
NO
Check No. 01
Check the indoor heat exchanger
thermistor.
As
described in the NO
thermistor characteristic Replace the indoor heat
chart? exchanger thermistor.
YES
Replace the indoor unit PCB
(control PCB).
(R20789)
4.4 Fan Motor (DC Motor) or Related Abnormality

Error Code A6
Method of Error The rotation speed detected by the Hall IC during fan motor operation is used to determine
Detection abnormal fan motor operation.
Error Decision The detected rotation speed does not reach the demanded rotation speed of the target tap, and
Conditions is less than 50% of the maximum fan motor rotation speed.
Supposed Remarkable decrease in power supply voltage

Causes Layer short inside the fan motor winding
Breaking of wire inside the fan motor
Breaking of the fan motor lead wires
Defective capacitor of the fan motor
Troubleshooting 20/25 class

Check No.03 Note: The motor may break when the
Turn off the power supply. motor connector is disconnected
Refer to P.98 (Unplug the power cable or turn with the power supply on.
the breaker off.) (Turn off the power supply before
connecting the connector also.)
Check the connector for ∗ To secure the connection,

connection. once disconnect the connector
and then reconnect it.
NO
OK? Correct the connection.
YES
YES
Foreign matters in or Remove the foreign matters.
around the fan?
NO
Rotate the fan by hand.
NO Abnormal NO
Fan rotates smoothly? sound occurs?
YES YES
Check No. 03
Check the fan motor for
breakdown or short circuit.
Rubber
cushion
Bearing
rubber
cushion
Is the rubber cushion YES

Replace the bearing rubber
properly fitted? cushion.
NO
Correct the position of
rubber cushion or replace
the rubber cushion.
NO
Resistance OK? Replace the indoor fan motor.
YES
Turn the power on again.
Check No. 03
Check the motor control voltage.
Is the motor control NO

voltage 15 VDC Replace the indoor unit PCB
generated? (control PCB).
YES
Check No. 03
Check the indoor unit PCB for
rotation pulse.
Is the rotation pulse NO

Replace the indoor fan motor.
generated?
YES
(control PCB). (R20976)
Troubleshooting 35/42/50 class

Check No.02
Refer to P.98 Check the power supply
voltage.
Is the
voltage
fluctuation NO
within ±10% from Correct the power
the rated supply.
value?
YES
Turn off the power and
rotate the fan by hand.
Does the fan NO

rotate smoothly? Replace the indoor
fan motor.
YES
Turn on the power and
start operation.
Turn off the power and Note: The motor may break when the
NO disconnect the fan motor motor connector is disconnected
Does the fan while the power is turned on.
rotate? connector, then turn the
power on. (Be sure to turn off the power
before reconnecting the
YES connector.)
Check No.02
Check the output of the
fan motor connector.
Motor
power supply NO
voltage 310 ~ 340 Replace the indoor
VDC? unit PCB (control
PCB).
YES
Motor
control voltage 15 NO
VDC generated? Replace the indoor
unit PCB (control
PCB).
YES
Rotation NO
Stop the fan motor. command voltage Replace the indoor
1 ~ 6.5 VDC? unit PCB (control
PCB).
Check No.02 YES
Check the output of the
fan motor connector. Rotation pulse NO Replace the indoor
generated? fan motor.
YES
Replace the indoor
unit PCB (control
NO PCB).
Rotation pulse
generated? Replace the indoor
fan motor.
YES
Replace the indoor
unit PCB (control
PCB). (R20411)
4.5 Thermistor or Related Abnormality (Indoor Unit)

Error Code C4, C9
Method of Error The temperatures detected by the thermistors determine thermistor errors.
Detection
Error Decision The voltage between the both ends of the thermistor is 4.96 V and more or 0.04 V and less
Conditions during compressor operation.
Supposed Disconnection of connector

Causes Thermistor corresponding to the error code is defective.
Troubleshooting
Check No.01
Refer to P.97 Check the connection of
connectors.
NO
Normal? Correct the connection.
YES
Check No. 01
Check the thermistor resistance
value.
NO
Normal? Replace the thermistor.
YES
(control PCB).
(R20412)
C4 : Indoor heat exchanger thermistor

C9 : Room temperature thermistor
4.6 Refrigerant Shortage

Error Code U0
Method of Error Refrigerant shortage is detected by checking the input current value and the compressor
Detection running frequency. If the refrigerant is short, the input current is lower than the normal value.
Error Decision The following conditions continue for 7 minutes.

Conditions
Input current × input voltage ≤ A × output frequency + B
Output frequency > C
A (constant) B (W) C (Hz)

20/25/35 class 640/256 0 55
42/50 class 2813/256 50 50
If the error repeats, the system is shut down.

Reset condition: Continuous run for about 60 minutes without any other error
Supposed Disconnection of the discharge pipe thermistor, indoor or outdoor heat exchanger thermistor,
Causes room or outdoor temperature thermistor
Closed stop valve
Refrigerant shortage (refrigerant leakage)
Poor compression performance of compressor
Defective electronic expansion valve
Troubleshooting
Check No.01
Refer to P.97
Any thermistor YES
disconnected? Replace the thermistor(s) in
position.
∗ Discharge pipe thermistor
∗ Indoor or outdoor heat exchanger thermistor
Check No.12 NO
∗ Room temperature thermistor
Refer to P.99 ∗ Outdoor temperature thermistor
YES
Stop valve closed? Open the stop valve.
NO
Check for refrigerant shortage.
Oil oozing at relay YES

pipe connections? Repair the pipe flare or
replace the union.
NO
Oil oozing at internal YES

piping?
NO NO Check the pipes for

Compressor vibrating
too much? improper contact and
correct them as required.
Replace the cracked pipe.
YES
Check the power transistor
harness for loosening.
Correct it as required. Also
replace the cracked pipe.
Check No. 12 NO
Electronic expansion valve Replace the electronic
functioning? expansion valve.
YES
Change for a specified amount of
fresh refrigerant.
NO
Refrigerant shortage error Completed.
again?
YES
Check No. 01 NG
Check the thermistors. Replace the defective
thermistor(s).
OK
Replace the outdoor unit PCB
(main PCB).
NO
Error again? Completed.
YES
Replace the compressor.
(R20401)
4.7 Low-voltage Detection or Over-voltage Detection

Error Code U2
Method of Error Indoor Unit
Detection
The zero-cross detection of the power supply is evaluated by the indoor unit PCB.
Outdoor Unit
Low-voltage detection:
An abnormal voltage drop is detected by the DC voltage detection circuit.
Over-voltage detection:
An abnormal voltage rise is detected by the over-voltage detection circuit.
Error Decision Indoor Unit

Conditions
There is no zero-cross detection in approximately 10 seconds.
Outdoor Unit
Low-voltage detection:
The voltage detected by the DC voltage detection circuit is below 150 ~ 180 V (depending on
the model).
The compressor stops if the error occurs, and restarts automatically after 3-minute standby.
Over-voltage detection:
An over-voltage signal is fed from the over-voltage detection circuit to the microcomputer.
The compressor stops if the error occurs, and restarts automatically after 3-minute standby.
Supposed Power supply voltage is not as specified.

Causes Defective DC voltage detection circuit
Defective over-voltage detection circuit
Defective PAM control part
Disconnection of compressor harness
Short circuit inside the fan motor winding
Noise
Momentary drop of voltage
Momentary power failure
Defective outdoor unit PCB
Troubleshooting
Check the power supply voltage.
Is the
voltage fluctuation NO
within ±10% from the Correct the power supply.
rated value?
YES
Check the connection of the
compressor harness.
Loose or YES
disconnected? Reconnect the harness.
NO
Does the
NO
outdoor fan rotate Replace the outdoor fan motor
smoothly? and the outdoor unit PCB
(main PCB).
YES
(Precaution before turning on the power again)

Make sure the power has been off for at
least 30 seconds.
Turn on
the power. System YES Disturbance factors
restarted? (Repeat a few ∗ Noise Check for such factors for a
times.) ∗ Power supply distortion long term.
NO
Error
again within 3 minutes NO
after turning on the Replace the outdoor
power? unit PCB (main PCB).
YES
Replace the indoor
unit PCB (control PCB).
(R20413)
4.8 Signal Transmission Error (Between Indoor Unit and

Outdoor Unit)
Error Code U4
Method of Error The data received from the outdoor unit in signal transmission is checked whether it is normal.
Detection
Error Decision The data sent from the outdoor unit cannot be received normally, or the content of the data is
Conditions abnormal.
Supposed Reduction of power supply voltage

Causes Wiring error
Breaking of the connecting wires between the indoor and outdoor units (wire No. 3)
Short circuit inside the fan motor winding
Disturbed power supply waveform
Troubleshooting
Check No.11 Check the power supply voltage.

Refer to P.99
Is the
voltage fluctuation NO
within ±10% from the Correct the power supply.
rated value?
YES
Check the indoor unit - outdoor
unit connection wires.
YES
Is there any wiring error? Correct the indoor unit -
outdoor unit connection wires.
NO
Check the voltage of the

connection wires on the indoor
terminal board between No. 1
and No. 3, and between No. 2
and No. 3.
NO
Properly insulated? Replace the connection wires
between the indoor unit and
outdoor unit.
YES
∗ Before you check the LED A, cancel

Check the LED A on the outdoor the standby electricity saving
unit PCB. function by starting fan operation
with the remote controller.
∗ Wait at least for 7 sec. after turning
on the power.
Continuously ON or OFF
Is LED A blinking? Diagnose the outdoor unit
PCB (main PCB).
Blink
Rotate the
outdoor fan by hand. NO
Does the outdoor fan rotate Replace the outdoor fan motor
smoothly? and the outdoor unit PCB
(main PCB).
YES
Check No.11
Check the power supply
waveform.
NO
Is there any disturbance? Replace the indoor unit PCB
(control PCB).
YES
Locate the cause of the
disturbance of the power
supply waveform, and correct
it.
(R21199)
4.9 Unspecified Voltage (Between Indoor Unit and Outdoor

Unit)
Error Code UA
Method of Error The supply power is detected for its requirements (pair type is different from multi type) by the
Detection indoor / outdoor transmission signal.
Error Decision The pair type and multi type are interconnected.
Conditions
Supposed Wrong models interconnected

Causes Wrong wiring of connecting wires
Wrong indoor unit PCB or outdoor unit PCB mounted
Troubleshooting
Check the combination of the
indoor and outdoor unit.
NO
OK? Match the compatible models.
YES
Are the NO
connecting wires connected Correct the connection.
properly?
YES
Check the code numbers
(2P012345, for example) of the
indoor and outdoor unit PCB
with the Parts List.
If not matched, change for the
correct PCB.
(R20435)
4.10 Outdoor Unit PCB Abnormality

Error Code E1
Method of Error The system checks if the microprocessor is working in order.
Detection The system checks if the zero-cross signal comes in properly.
Error Decision The microprocessor program runs out of control.

Conditions The zero-cross signal is not detected.
Supposed Defective outdoor unit PCB

Causes Broken harness between PCBs
Noise
Momentary drop of voltage
Momentary power failure
Troubleshooting 20/25/35 class

∗ Before you check the LED A,
Turn on the power again. cancel the standby electricity
saving function by starting fan
operation with the remote
controller.
∗ Wait at least for 7 sec. after
turning on the power.
Is LED A blinking? Replace the outdoor unit
PCB (main PCB).
Blink
Check if the outdoor unit is
grounded.
NO
Grounded? Ground the system.
YES
Is the harness NO
Zero-cross signal
broken? abnormality.
Replace the outdoor unit
YES PCB (filter PCB).
Replace the harness.
(R21200)
Troubleshooting 42/50 class

∗ Before you check the LED A,
Turn on the power again. cancel the standby electricity
saving function by starting fan
operation with the remote
controller.
∗ Wait at least for 7 sec. after
turning on the power.
Is LED A blinking? Replace the outdoor unit
PCB (main PCB).
Blink
Check if the outdoor unit is
grounded.
NO
Grounded? Ground the system.
YES
Zero-cross signal
abnormality.
PCB (main PCB).
(R21201)
4.11 OL Activation (Compressor Overload)

Error Code E5
Method of Error A compressor overload is detected through compressor OL.
Detection
Error Decision If the error repeats, the system is shut down.

Conditions Reset condition: Continuous run for about 60 minutes without any other error
Supposed Disconnection of discharge pipe thermistor

Causes Defective discharge pipe thermistor
Disconnection of connector S40
Disconnection of 2 terminals of OL (Q1L)
Defective OL (Q1L)
Broken OL harness
Defective electronic expansion valve or coil
Defective four way valve or coil
Refrigerant shortage
Water mixed in refrigerant
Defective stop valve
Troubleshooting
Check No.01
Refer to P.97
Discharge YES
pipe thermistor Insert the thermistor in
disconnected? position.
Check No.12
NO
Refer to P.99
Check No. 01 NG
Check the thermistors. Replace the discharge pipe
∗ Discharge pipe thermistor thermistor.
Check No.13
Refer to P.100 OK
Connectors are NO
properly connected? Connect the connectors
Check No.14 ∗ Connector S40 properly.
∗ 2 terminals of OL (Q1L)
Refer to P.100 YES
Disconnect the connector S40
from the PCB.
Check Resistance
the resistance ∞
between the 2 terminals on Disconnect the 2 terminals of
connector S40. the OL (Q1L).
Nearly 0 Ω Check the Resistance

resistance between the ∞
2 terminals of the OL Replace the OL (Q1L).
(Q1L).
Nearly 0 Ω
Replace the OL harness.
Check No. 12 NG
Check the electronic Replace the electronic
expansion valve. expansion valve or the coil.
OK
Check No. 13 NG
Check the four way Replace the four way valve
valve. or the coil.
OK PCB (main PCB).
Check No. 14 NG
Check the refrigerant ∗ Refrigerant shortage Refer to the refrigerant line
line. ∗ Water mixed check procedure.
∗ Stop valve
OK
PCB (main PCB).
(R20415)
Note: OL (Q1L) activating temperature: 120°C

OL (Q1L) recovery temperature: 95°C
4.12 Compressor Lock

Error Code E6
Method of Error A compressor lock is detected by checking the compressor running condition through the
Detection position detection circuit.
Error Decision Operation stops due to overcurrent.

Conditions If the error repeats, the system is shut down.
Supposed Compressor locked

Causes Compressor harness disconnected
Troubleshooting
(Precaution before turning on the power again)
Check No.12 Make sure the power has been off for at least 30 seconds.
Refer to P.99
Turn off the power. Disconnect the
harnesses U, V, and W.
Check No.15
Refer to P.101 Check No.15 ∗ Inverter analyzer:
Check with the inverter analyzer. RSUK0917C
NO
Any LED off? Correct the power supply or
replace the outdoor unit
PCB (main PCB).
YES
Turn off the power and reconnect
the harnesses. Turn on the power
again and restart the system.
Emergency YES
stop without compressor Replace the compressor.
running?
NO
System shut NO
down after errors repeated Check the electronic
several times? expansion valve coil.
Replace it as required.
Go to Check No. 12.
YES
(R21163)
4.13 DC Fan Lock

Error Code E7
Method of Error An error is determined with the high-voltage fan motor rotation speed detected by the Hall IC.
Detection
Error Decision The fan does not start in about 15 ~ 30 seconds even when the fan motor is running.
Conditions If the error repeats, the system is shut down.
Supposed Disconnection of the fan motor

Causes Foreign matter stuck in the fan
Defective fan motor
Troubleshooting
Check No.16
Fan motor connector YES
Refer to P.102 Turn off the power and
disconnected?
reconnect the connector.
NO
Foreign matters in or YES

around the fan? Remove the foreign
matters.
NO
Turn on the power.
Rotate the fan.
Fan rotates NO
smoothly? Replace the outdoor fan
motor.
YES
Check No. 16
Check the rotation pulse input on
the outdoor unit PCB (main PCB).
NO
Pulse signal generated? Replace the outdoor fan
motor.
YES
PCB (main PCB).
(R20416)
4.14 Input Overcurrent Detection

Error Code E8
Method of Error An input overcurrent is detected by checking the input current value with the compressor
Detection running.
Error Decision The current exceeds about 9.25 ~ 10 A (depending on the model) for 2.5 seconds with the
Conditions compressor running.
(The upper limit of the current decreases when the outdoor temperature exceeds a certain
level.)
Supposed Outdoor temperature is out of operation range.

Causes Defective compressor
Defective power module
Short circuit
Troubleshooting
Check No.15 ∗ An input overcurrent may result from wrong internal wiring. If the system is interrupted by an input
Refer to P.101 overcurrent after the wires have been disconnected and reconnected for part replacement, check the
wiring again.
Check No. 17
Check No.17 Check the installation condition.
Refer to P.103
Start operation and measure the
input current.
Check No.18
Refer to P.104
Input current flowing NO NO
above its stop level? Is the fuse (+) blown? Replace the outdoor unit
PCB (main PCB and filter
PCB).
YES YES
Replace the fuse.
Turn off the power and disconnect
the harnesses U, V, and W.
Check No.15 ∗ Inverter analyzer:

YES
Any LED off? Correct the power supply or
PCB (main PCB).
NO
Turn off the power, and reconnect
again and start operation.
Check No. 18
Check the discharge pressure.
(R20437)
FU3
4.15 Four Way Valve Abnormality

Error Code EA
Method of Error The room temperature thermistor and the indoor heat exchanger thermistor are checked if they
Detection function within their normal ranges in each operation mode.
Error Decision A following condition continues over 10 minutes after operating for 5 minutes.
Conditions
< Cooling / Dry >
A – B < –5°C
< Heating >

B – A < –5°C
A: Room thermistor temperature

B: Indoor heat exchanger temperature

Supposed Disconnection of four way valve coil

Causes Defective four way valve, coil, or harness
Defective thermistor
Troubleshooting
Check No.01 YES

Four way valve coil
Refer to P.97 disconnected (loose)? Correct the four way valve
coil.
NO
Check No.13
YES
Refer to P.100 Harness disconnected? Reconnect the harness.
NO
Check No.14 Check the continuity of the four way
Refer to P.100 valve coil and harness.
Disconnect the harness from the

connector.
Resistance NO
between harnesses about Replace the four way
1000 ~ 2000 Ω? valve coil.
YES
Check No. 13 NG
Check the four way valve Replace the outdoor
switching output. unit PCB (main PCB).
OK
Any thermistor YES

disconnected? Reconnect the
thermistor(s).
NO
Check No. 01 NG
thermistor(s).
OK
Check No. 14 NG
Check the refrigerant Refer to the refrigerant line
line. ∗ Refrigerant shortage check procedure.
∗ Water mixed
OK ∗ Stop valve
Replace the four way valve

(defective or dust-clogged).
(R21202)
4.16 Discharge Pipe Temperature Control

Error Code F3
Method of Error An error is determined with the temperature detected by the discharge pipe thermistor.
Detection
Error Decision If the temperature detected by the discharge pipe thermistor rises above A°C, the
Conditions compressor stops.
The error is cleared when the discharge pipe temperature has dropped below B°C.
<20/25/35 class>
A (°C) B (°C)
(1) above 50 Hz (rising), above 45 Hz (dropping) 118 85
(2) 39 ~ 50 Hz (rising), 34 ~ 45 Hz (dropping) 113 80
(3) below 39 Hz (rising), below 34 Hz (dropping) 103 70
<42/50 class>
A (°C) B (°C)
(1) above 50 Hz (rising), above 45 Hz (dropping) 118 85
(2) 21 ~ 50 Hz (rising), 16 ~ 45 Hz (dropping) 106 73
(3) below 21 Hz (rising), below 16 Hz (dropping) 98 65

Supposed Defective discharge pipe thermistor

Causes (Defective outdoor heat exchanger thermistor or outdoor temperature thermistor)
Defective four way valve
Troubleshooting
Check No.01
Refer to P.97 Check No. 01 NG
∗ Discharge pipe thermistor thermistor(s).
∗ Outdoor heat exchanger thermistor
OK ∗ Outdoor temperature thermistor
Check No.12
Refer to P.99 Check No. 12 NG
Check the electronic Replace the electronic
Check No.14 OK
Refer to P.100
Check No. 14 NG
Check the refrigerant Refer to the refrigerant line
line. ∗ Refrigerant shortage check procedure.
∗ Four way valve
OK ∗ Water mixed
∗ Stop valve
PCB (main PCB).
(R20417)
4.17 High Pressure Control in Cooling

Error Code F6
Method of Error High-pressure control (operation halt, frequency drop, etc.) is activated in cooling operation if
Detection the temperature sensed by the outdoor heat exchanger thermistor exceeds the limit.
Error Decision The temperature sensed by the outdoor heat exchanger thermistor rises above 53 ~ 57°C
Conditions (depending on the model).
The error is cleared when the temperature drops below 48 ~ 50°C (depending on the
model).
Supposed The installation space is not large enough.

Causes Dirty outdoor heat exchanger
Defective outdoor fan motor
Defective outdoor heat exchanger thermistor
Troubleshooting
Check No.01
Check the installation space.
Refer to P.97
Check No.12 Check No. 17 NG

Check the installation Change the installation
Refer to P.99 condition. location or direction.
Clean the outdoor heat
OK exchanger.
Check No.17
Check No. 19 NG
Refer to P.103 Check the outdoor fan. Replace the outdoor fan
motor.
Reconnect the connector or
OK fan motor lead wires.
Check No.18
Check No. 18 NG
Refer to P.104 Check the discharge Replace the stop valve.
pressure.
OK
Check No.19
Check No. 12
Refer to P.104 Check the electronic
NG
Replace the electronic
OK PCB (main PCB).
Check No. 01
Check the outdoor heat NG
Replace the outdoor heat
exchanger thermistor. exchanger thermistor.
OK

PCB (main PCB).
(R20418)
4.18 Compressor System Sensor Abnormality

Error Code H0
Method of Error The system checks the DC current before the compressor starts.
Detection
Error Decision The DC current before compressor start-up is out of the range 0.5 ~ 4.5 V (sensor output
Conditions converted to voltage value).
The DC voltage before compressor start-up is below 50 V.
Supposed Broken or disconnected harness

Causes Defective outdoor unit PCB
Troubleshooting
Check the relay harness for the

compressor.
YES
Is the harness broken? Replace the harness.
NO
Turn off the power. Then, turn on

the power to restart the system.
Restart operation NO
and error displayed No problem.
again? Keep on running.
YES
PCB (main PCB).
(R21434)
4.19 Position Sensor Abnormality

Error Code H6
Method of Error A compressor start-up failure is detected by checking the compressor running condition through
Detection the position detection circuit.

Supposed Disconnection of the compressor relay cable

Causes Defective compressor
Start-up failure caused by the closed stop valve
Input voltage is outside the specified range.
Troubleshooting
Check No.15
Refer to P.101 Turn off the power.
Check No.18 Check the power supply voltage.

Refer to P.104
NO
Voltage as rated? Correct the power supply.
Check No.20
Refer to P.105
YES
Check No. 18
Check the discharge pressure.
NO
OK? Replace the stop valve.
YES
Check No. 20
Check the short circuit of the diode
bridge.
NO
Normal? Replace the outdoor unit
PCB (main PCB).
YES
Check the connection.
Electrical
components or NO
compressor harnesses Reconnect the electrical
connected as components or compressor
specified? harnesses as specified.
YES
Turn on the power. Check the
electrolytic capacitor voltage.
NO
320 ± 50 VDC? Replace the outdoor unit
PCB (main PCB).
YES
Turn off the power. Disconnect the
harnesses U, V, and W.

NO
Any LED OFF? Replace the compressor.
YES
Correct the power supply or
PCB (main PCB).
(R20422)
4.20 DC Voltage / Current Sensor Abnormality (20/25/35 Class

Only)
Error Code H8
Method of Error DC voltage or DC current sensor abnormality is identified based on the compressor running
Detection frequency and the input current.

Supposed Defective outdoor unit PCB

Causes
Troubleshooting
Replace the outdoor unit PCB (main PCB).
4.21 Thermistor or Related Abnormality (Outdoor Unit)

Error Code H9, J3, J6, P4
Method of Error This fault is identified based on the thermistor input voltage to the microcomputer.
Detection A thermistor fault is identified based on the temperature sensed by each thermistor.
Error Decision The voltage between the both ends of the thermistor is 4.96 V and more or 0.04 V and less
Conditions during compressor operation.
J3 error is judged if the discharge pipe temperature is lower than the heat exchanger
temperature.
Supposed Disconnection of the connector for the thermistor

Causes Thermistor corresponding to the error code is defective.
Defective heat exchanger thermistor in the case of J3 error (outdoor heat exchanger
thermistor in cooling operation, or indoor heat exchanger thermistor in heating operation)
Troubleshooting In case of P4
Replace the outdoor unit PCB (main PCB).
P4 : Radiation fin thermistor
Troubleshooting In case of H9, J3, J6

Check No.01
Refer to P.97 Turn on the power again.
Error displayed NO
again on remote Reconnect the connectors
controller? or thermistors.
YES
Check No. 01
Check the thermistor resistance
value.
NO
Normal? Replace the defective
thermistor(s) of the following
J3 error: the discharge thermistors.
pipe temperature is YES ∗ Outdoor temperature
lower than the heat thermistor
exchanger temperature. ∗ Discharge pipe thermistor
Cooling: Outdoor heat ∗ Outdoor heat exchanger
exchanger thermistor
temperature
Heating: Indoor heat
exchanger
temperature
Check No. 01
Check the indoor heat exchanger
thermistor resistance value in the
heating operation.
Indoor heat NO
exchanger thermistor Replace the indoor heat
functioning? exchanger thermistor.
YES
PCB (main PCB).
(R20406)
H9 : Outdoor temperature thermistor

J3 : Discharge pipe thermistor
J6 : Outdoor heat exchanger thermistor
4.22 Electrical Box Temperature Rise

Error Code L3
Method of Error An electrical box temperature rise is detected by checking the radiation fin thermistor with the
Detection compressor off.
Error Decision With the compressor off, the radiation fin temperature is above A°C.
Conditions The error is cleared when the radiation fin temperature drops below B°C.
To cool the electrical components, the outdoor fan starts when the radiation fin temperature
rises above C°C. The outdoor fan stops when the radiation fin temperature drops below
B°C.
A (°C) B (°C) C (°C)
20/25/35 class 98 75 83
42/50 class 90 64 81
Supposed Defective outdoor fan motor

Causes Short circuit
Defective radiation fin thermistor
Troubleshooting
Check No.17 WARNING
Refer to P.103 the power to restart the system. To cool the electrical components, the
outdoor fan starts when the radiation
fin temperature rises above C ˚C. The
outdoor fan stops when the radiation
Check No.19 fin temperature drops below B ˚C.
Refer to P.104 YES
Error again or outdoor
fan activated?
NO
Check the radiation fin
temperature.
NO
Above A˚C? Replace the outdoor unit
PCB (main PCB).
YES
Check No. 19 NG
Check the outdoor fan. Replace the outdoor fan
motor.
Correct the connectors
OK and fan motor lead wire.
PCB (main PCB).
NO
Radiation fin dirty? Check the installation
condition.
Go to Check No. 17.
YES
Clean up the radiation fin.
(R21436)
4.23 Radiation Fin Temperature Rise

Error Code L4
Method of Error A radiation fin temperature rise is detected by checking the radiation fin thermistor with the
Detection compressor on.
Error Decision If the radiation fin temperature with the compressor on is above A°C.
Conditions The error is cleared when the radiation fin temperature drops below B°C.
A (°C) B (°C)
20/25/35 class 98 78
42/50 class 100 57
Supposed Defective outdoor fan motor

Causes Short circuit
Defective radiation fin thermistor
Silicon grease is not applied properly on the radiation fin after replacing the outdoor unit
PCB.
Troubleshooting
Check No.17
Refer to P.103 the power to restart the system.
Check No.19 YES Has the PCB been YES

Error displayed again? Check if silicon grease is
Refer to P.104 replaced? applied properly on the
radiation fin. If not, apply
NO NO the silicon grease.
Check the radiation fin
temperature.
NO
Above A ˚C? Replace the outdoor unit
PCB (main PCB).
YES
Check No. 19 NG
Check the outdoor fan. Replace the outdoor fan
motor.
Correct the connectors and
OK fan motor leads.
PCB (main PCB).
NO
Radiation fin dirty? Check the installation
condition.
Go to Check No. 17.
YES
Clean up the radiation fin.
(R21437)
Note: Refer to Silicon Grease on Power Transistor / Diode Bridge on page 115 for detail.
4.24 Output Overcurrent Detection

Error Code L5
Method of Error An output overcurrent is detected by checking the current that flows in the inverter DC section.
Detection
Error Decision A position signal error occurs while the compressor is running.
Conditions A rotation speed error occurs while the compressor is running.
An output overcurrent signal is fed from the output overcurrent detection circuit to the
microcomputer.
Supposed Poor installation condition

Causes Closed stop valve
Defective power module
Wrong internal wiring
Abnormal power supply voltage
Defective compressor
Troubleshooting
Check No.15 ∗ An output overcurrent may result from wrong internal wiring. If the system is interrupted by an output
Refer to P.101 overcurrent after the wires have been disconnected and reconnected for part replacement, check the
wiring again.
Check No. 17
Check No.17 Check the installation condition.
Refer to P.103
NO
Stop valve fully open? Fully open the stop valve.
Check No.18
Refer to P.104 YES
Check No.22 See if the same error occurs.
Refer to P.106
NO Monitor the power supply voltage,
Error again? discharge and suction pressures,
and other factors for a long term.
YES Possible causes
∗ Momentary drop of power supply Not a malfunction.
Turn off the power and disconnect voltage
the harnesses U, V, and W. Keep observing.
∗ Compressor overload
∗ Short circuit Check the connectors and
other components.

YES
Any LED off? Correct the power supply
or replace the outdoor unit
PCB (main PCB).
NO
Check No. 22
Check the power module.
NO
Normal? Replace the outdoor unit
PCB (main PCB).
YES
Turn off the power, and reconnect
again and start operation.
Check the power supply voltage.
NO
Voltage as rated? Correct the power supply.
YES
Short circuit or NO
wire breakage between Check the discharge
compressor's coil pressure.
phases? Go to Check No. 18.
YES
(R21438)
Check SiBE041434E
5. Check
5.1 Thermistor Resistance Check
Check No.01 Disconnect the connectors of the thermistors from the PCB, and measure the resistance of
each thermistor using a multimeter.
The data is for reference purpose only.

Resistance (kΩ)
Thermistor temperature (°C) Room temperature thermistor Other thermistors
of 20/25 class models
–20 73.4 197.8
–15 57.0 148.2
–10 44.7 112.1
–5 35.3 85.60
0 28.2 65.93
5 22.6 51.14
10 18.3 39.99
15 14.8 31.52
20 12.1 25.02
25 10.0 20.00
30 8.2 16.10
35 6.9 13.04
40 5.8 10.62
45 4.9 8.707
50 4.1 7.176
(R25°C = 10 kΩ, B = 3435 K) (R25°C = 20 kΩ, B = 3950 K)
Room temperature thermistor Other thermistors

(kΩ) of 20/25 class models (kΩ)
50 150
100
25
50
0
–15 0 15 30 45 (˚C) –15 0 15 30 45 (˚C) (R11952)
Room temperature
thermistor
Multimeter
Resistance range
Multimeter
(R21542) (R20505)
When the room temperature thermistor is soldered on a PCB, remove the PCB from the
control PCB to measure the resistance.
When the connector of indoor heat exchanger thermistor is soldered on a PCB, remove the
thermistor and measure the resistance.
SiBE041434E Check
5.2 Fan Motor Connector Output Check

Check No.02 35/42/50 class
1. Check the connection of connector.
2. Check the motor power supply voltage output (pins 4 - 7).
3. Check the motor control voltage (pins 4 - 3).
4. Check the rotation command voltage (pins 4 - 2).
5. Check the rotation pulse (pins 4 - 1).
S1
7 Motor power supply voltage (310 ~ 340 VDC)
6 Unused
5 Unused
4 GND
3 Motor control voltage (15 VDC)
2 Rotation command voltage (1~ 6.5 VDC)
1 Rotation pulse input
(R19654)
Check No.03 20/25 class

Fan motor wire breakdown / short circuit check
1. Check the connector for connection.
2. Turn the power off.
3. Check if each resistance at the phases U - V and V - W is 90 Ω ~ 100 Ω (between the pins
12 - 9, and between 9 - 6).
Motor control voltage check

2. Check the motor control voltage is generated (between the pins 2 - 3).
Rotation pulse check

2. Turn the power on and stop the operation.
3. Check if the Hall IC generates the rotation pulse 4 times when the fan motor is manually
rotated once (between the pins 1 - 3).
S200
12 Phase U
11 Free pin
10 Free pin
9 Phase V
8 Free pin
7 Free pin
6 Phase W
5 Free pin
4 Free pin
3 GND
2 Motor control voltage (15 VDC)
1 Rotation pulse (5 VDC)

(R11979)
Check SiBE041434E
5.3 Power Supply Waveforms Check

Check No.11 Measure the power supply waveform between No. 1 and No. 2 on the terminal board, and check
the waveform disturbance.
Check if the power supply waveform is a sine wave (Fig.1).
Check if there is waveform disturbance near the zero-cross (sections circled in Fig.2).
Fig.1 Fig.2
(R1444)
(R1736)
5.4 Electronic Expansion Valve Check

Check No.12 Conduct the followings to check the electronic expansion valve (EV).
1. Check if the EV connector is correctly connected to the PCB.
2. Turn the power off and on again, and check if the EV generates a latching sound.
3. If the EV does not generate a latching sound in the above step 2, disconnect the connector
and check the continuity using a multimeter.
4. Check the continuity between the pins 1 - 6, 2 - 6, 3 - 6, 4 - 6. If there is no continuity
between the pins, the EV coil is faulty.
5. If the continuity is confirmed in step 3, the outdoor unit PCB is faulty.
Harness 5P
1-6
(5)
2-6
S20 6P Connector Check
3-6
4-6
1 2 3 4 5 6
(R16386)
SiBE041434E Check
5.5 Four Way Valve Performance Check

Check No.13

∗ Four way valve coil

Start heating operation. Cooling / Dry: Not energized
Heating: Energized
S80
voltage at 220 - 240 NO
VAC with compressor Replace the outdoor unit
on? (Fig. 1) PCB (main PCB).
YES
Disconnect the four way valve coil
from the connector and check the
continuity.
Four way NO
valve coil resistance at Replace the four way valve
1000 ~ 2000 Ω? coil.
YES
Replace the four way valve.
(R21439)
(Fig. 1)
Voltage at S80
220 - 240 VAC
Time
Compressor
ON
(R11904)
5.6 Inverter Unit Refrigerant System Check

Check No.14
Refrigerant system check
Is the
discharge pipe YES
thermistor disconnected Reconnect the thermistor.
from the holder?
NO
Check for refrigerant leakage.
See the service diagnosis on
refrigerant shortage (U0).
Replace the refrigerant.
(R15833)

Check SiBE041434E
5.7 Inverter Analyzer Check

Check No.15 Characteristics
Inverter analyzer: RSUK0917C
If an abnormal stop occurs due to compressor startup failure or overcurrent output when using
an inverter unit, it is difficult to judge whether the stop is caused by the compressor failure or
some other failure (main PCB, power module, etc.). The inverter analyzer makes it possible to
judge the cause of trouble easily and securely. (Connect an inverter analyzer as a quasi-
compressor instead of compressor and check the output of the inverter.)
Operation Method
Step 1
Be sure to turn the power off.
Step 2
Install an inverter analyzer instead of a compressor.
Note:
Make sure the charged voltage of the built-in smoothing electrolytic capacitor drops to 10
VDC or below before carrying out the service work.
(2) Connect the terminals to the
(1) Remove the terminals from terminals of the inverter
the compressor. analyzer.
Compressor
Inverter analyzer
Be careful not to let the terminals (U,V,W)

touch each other. Otherwise, high voltage
is applied.
(R18322)
Reference:
If the terminals of the compressor are not FASTON terminals (difficult to remove the wire on
the terminals), it is possible to connect wires available on site to the outdoor unit from output
side of PCB. (Do not connect them to the compressor at the same time, otherwise it may
result in incorrect detection.)
Step 3
Activate power transistor test operation from the indoor unit.
(1) Turn the power on.
(2) Select FAN operation with the Mode button on the remote controller.
(3) Press the center of the Temp button and the Mode button at the same time.
(4) Select T with the Temp or Temp button.
(5) Press the Mode button to start the power transistor test operation.

SiBE041434E Check
Diagnose method (Diagnose according to 6 LEDs lighting status.)

(1) If all the LEDs are lit uniformly, the compressor is defective.
→ Replace the compressor.
(2) If the LEDs are not lit uniformly, check the power module.
→ Refer to Check No.22.
(3) If NG in Check No.22, replace the power module.
(Replace the main PCB. The power module is united with the main PCB.)
If OK in Check No.22, check if there is any solder cracking on the PCB.
(4) If any solder cracking is found, replace the PCB or repair the soldered section.
If there is no solder cracking, replace the PCB.
Caution
(1) When the output frequency is low, the LEDs blink slowly. As the output frequency increases,
the LEDs blink quicker. (The LEDs look like they are lit.)
(2) On completion of the inverter analyzer diagnosis, be sure to re-crimp the FASTON terminals.
Otherwise, the terminals may be burned due to loosening.
Direction of crimp
This size is shortened

by the crimp.
FASTON terminal
(R19646)
5.8 Rotation Pulse Check on the Outdoor Unit PCB

Check No.16 20/25/35 class
1. Check that the control voltage between the pins 10 - 11 is 15 VDC.
2. Check if the Hall IC generates the rotation pulse (0 ~ 15 VDC) 4 times between the pins 10 -
12, 10 - 13, when the fan motor is manually rotated once.
S70
13 HV (Hall IC)
12 HU (Hall IC)
11 Control voltage 15 VDC
10
9 Free pin
8 Free pin
7 Phase W
6 Free pin
5 Free pin
4 Phase V
3 Free pin
2 Free pin
1 Phase U
(R19957)

Check SiBE041434E
42/50 class
Make sure that the voltage of 320 ± 30 V is applied.
1. Set operation off and power off. Disconnect the connector S70.
2. Check that the voltage between the pins 4 - 7 is 320 VDC.
3. Check that the control voltage between the pins 3 - 4 is 15 VDC.
4. Check that the rotation command voltage between the pins 2 - 4 is 0 ~ 6.5 VDC.
5. Keep operation off and power off. Connect the connector S70.
6. Check whether 4 rotation pulses (0 ~ 15 VDC) are input at the pins 1 - 4 when the fan motor
is rotated 1 turn by hand.
When the fuse is melted, check the outdoor fan motor for proper function.
If NG in step 2 → Defective PCB → Replace the outdoor unit PCB (main PCB).
If NG in step 4 → Defective Hall IC → Replace the outdoor fan motor.
If OK in both steps 2 and 4 → Replace the outdoor unit PCB (main PCB).
PCB
S70
1 Actual rotation pulse input (0 ~ 15 VDC)
2 Rotation command voltage (0 ~ 6.5 VDC)
3 Control voltage 15 VDC
4
5
6
7 320 VDC
(R19655)
5.9 Installation Condition Check

Check No.17
Installation condition check
Check the allowable NG

dimensions of the air Change the installation
suction and location or direction.
discharge area.
OK
Is the discharged air YES

Change the installation
short-circuited? location or direction.
NO
Is the outdoor heat YES

exchanger very dirty? Clean the outdoor heat
exchanger.
NO
Is the airflow blocked by NO

obstacles or winds Check the outdoor
blowing in the opposite temperature. (The outdoor
direction? temperature should be
within the operation range.)
YES
Change the installation location
or direction.
(R19401)

SiBE041434E Check
5.10 Discharge Pressure Check

Check No.18
Discharge pressure check
NO
High? Replace the compressor.
YES
NO
Is the stop valve open? Open the stop valve.
YES
Is the connection pipe YES

Replace the pipe installed at
deformed? the site.
NO
Is the air
filter or indoor / outdoor NO
heat exchanger Replace the compressor.
dirty?
YES
Clean the dirty air filter or
indoor / outdoor heat
exchanger.
(R19385)
5.11 Outdoor Fan System Check

Check No.19 DC motor
Check the outdoor fan system.
Is the NO Fan motor NO

outdoor fan running? lead wire connector Go to Check No. 16.
disconnected?
YES YES
Outdoor fan system is functioning. Reconnect the connector.

(R21195)

Check SiBE041434E
5.12 Main Circuit Short Check

Check No.20 Check to make sure that the voltage between (+) and (–) of the diode bridge (DB1) is
approximately 0 V before checking.
Measure the resistance between the pins of the DB1 referring to the table below.
If the resistance is ∞ or less than 1 kΩ, short circuit occurs on the main circuit.
Positive terminal (+) of
digital multimeter ~ (2, 3) + (4) ~ (2, 3) – (1)
Negative terminal (–) of
digital multimeter + (4) ~ (2, 3) – (1) ~ (2, 3)
Resistance is OK. several kΩ ~ several MΩ
Resistance is NG. 0 Ω or ∞
20/25/35 class
– ~ ~ +
1
– +
Multimeter
2
(R19933)
42/50 class
– ~ ~ +
2
– +
Multimeter
1
(R21203)

SiBE041434E Check
5.13 Power Module Check

Check No.22 Check to make sure that the voltage between (+) and (–) of the power module is
approximately 0 V before checking.
Disconnect the compressor harness connector from the outdoor unit PCB. To disengage the
connector, press the protrusion on the connector.
Follow the procedure below to measure resistance between the (+) or (–) terminal of the
power module and the U, V, or W terminal of the compressor with a multimeter. Evaluate the
measurement results referring to the following table.
Positive terminal (+) of Power module UVW Power module UVW

digital multimeter (+) (–)
Negative terminal (–) of UVW Power module UVW Power module
digital multimeter (+) (–)
Resistance is OK. several kΩ ~ several MΩ
Resistance is NG. 0 Ω or ∞
20/25/35 class
V U
DC +
Power module (+)
W
DC –
Power module (–)
(R20794)

Check SiBE041434E
42/50 class
W
V
U
DC_P1
Power module (+)
DC_N1
Power module (–) (R21204)

SiBE041434E
Part 7
Trial Operation and
Field Settings
1. Pump Down Operation........................................................................109
2. Forced Cooling Operation ...................................................................110
3. Trial Operation ....................................................................................111
4. Field Settings ......................................................................................112
4.1 When 2 Units are installed in 1 Room ..................................................112
4.2 Model Type Setting ..............................................................................112
4.3 Facility Setting (cooling at low outdoor temperature) ...........................113
4.4 Jumper Settings ...................................................................................114
5. Silicon Grease on Power Transistor / Diode Bridge............................115
Trial Operation and Field Settings 108

Pump Down Operation SiBE041434E
1. Pump Down Operation

Outline In order to protect the environment, be sure to conduct pump down operation when relocating or
disposing of the unit.
Detail 1) Remove the valve caps from the liquid stop valve and the gas stop valve.
2) Carry out forced cooling operation.
3) After 5 to 10 minutes, close the liquid stop valve with a hexagonal wrench.
4) After 2 to 3 minutes, close the gas stop valve and stop the forced cooling operation.
Hexagonal
wrench
Close
Liquid stop valve
Gas stop valve Valve cap

Service port (R13628)
Refer to forced cooling operation on Page 110.
109 Trial Operation and Field Settings

SiBE041434E Forced Cooling Operation
2. Forced Cooling Operation

Item Forced Cooling
Conditions The forced cooling operation is allowed when both of the following conditions are
met.
1) The outdoor unit is not abnormal and not in the 3-minute standby mode.
2) The outdoor unit is not operating.
Start Press the forced cooling operation ON/OFF button (S1W) on the indoor unit for 5
seconds.
Command 20/25/35 class: 58 Hz
frequency 42/50 class: 30 Hz
End The forced cooling operation ends when any of the following conditions are fulfilled.
1) The operation ends automatically after 15 minutes.

2) Press the forced cooling operation ON/OFF button (S1W) on the indoor unit again.
3) Press the On/Off button on the remote controller.
Others Protection functions have priority over all other functions during forced cooling
operation.
Indoor Unit: 20/25 class
ON/OFF button (SW1)

(R21339)
Indoor Unit: 35/42/50 class
ON/OFF button (SW1)
(R21340)

Trial Operation SiBE041434E
3. Trial Operation
Outline Carry out the trial operation in accordance with the operation manual to ensure that all functions
and parts, such as flap movement, are working properly.
Trial operation should be carried out in either cooling or heating operation.
Detail 1. Measure the power supply voltage and make sure that it falls within the specified range.
2. In cooling operation, select the lowest programmable temperature (18°C); in heating
operation, select the highest programmable temperature (30°C).
Trial operation may be disabled in either operation mode depending on the room
temperature.
After trial operation is complete, set the temperature to a normal level (26°C ~ 28°C in
cooling, 20°C ~ 24°C in heating operation).
For protection, the system does not start for 3 minutes after it is turned off.
ARC466 Series
(1) Press the On/Off button to turn on the system.
(2) Press the center of the Temp button and the Mode button at the same time.
(3) Select T (trial operation) with the Temp or Temp button.
(4) Press the Mode button to start the trial operation.
(5) Press the Mode button and select operation mode.
(6) Trial operation terminates in approximately 30 minutes and switches into normal mode. To
quit trial operation, press the On/Off button.
(3)
(2) (3)
(2) (4) (5) (1) (6) (R19935)

SiBE041434E Field Settings
4. Field Settings
4.1 When 2 Units are installed in 1 Room
Outline When 2 indoor units are installed in 1 room, 1 of the 2 indoor units and the corresponding
wireless remote controller can be set for different addresses.
Both the indoor unit PCB and the wireless remote controller need alteration.
Indoor Unit PCB Cut the address setting jumper JA on the control PCB.
20/25 class 35/42/50 class
JC
JA
ADDRESS
JB
JA
JA ADDRESS
JA ADDRESS EXIST 1
EXIST 1 CUT 2
CUT 2
(R18258) (R18414)

them.
Wireless Remote Cut the address setting jumper.

Controller
ADDRESS Jumper
EXIST 1
CUT 2
∗ Do not cut the left jumper.

(R18416)
Caution Replace the remote controller if you cut the jumper on the left side.
The heating operation will not be available when the jumper on the left side is cut.
4.2 Model Type Setting

This remote controller is common to the heat pump model and cooling only model.
Never cut this jumper.
(R18451)
Caution Replace the remote controller if you cut the jumper on the left side.
The heating operation will not be available when the jumper on the left side is cut.

Field Settings SiBE041434E
4.3 Facility Setting (cooling at low outdoor temperature)

Outline This function is limited only for facilities (the target of air conditioning is equipment (such as
computer)). Never use it in a residence or office (the space where there is a human).
Detail You can expand the operation range to –15°C by cutting the jumper on the outdoor unit PCB.
Note that the operation may stop if the outdoor temperature drops below –15°C. If the outdoor
temperature rises, the operation starts again.
20/25/35 class
Main PCB
J3
J4
J5
S40
S70
Cut the jumper J4.
S90 S2
(R18253)
42/50 class
Cut the jumper J6.
(R21209)

them.
Caution 1. If the outdoor unit is installed where the outdoor heat exchanger of the unit is exposed to
direct wind, provide a windbreak wall.
2. Intermittent noises may be produced by the indoor unit due to the outdoor fan turning on and
off when using facility settings.
3. Do not place humidifiers or other items which might raise the humidity in rooms where facility
settings are being used.
A humidifier might cause dew condensation from the indoor unit outlet vent.
4. Cutting the jumper sets the indoor fan tap to the highest position.

SiBE041434E Field Settings
4.4 Jumper Settings

Indoor Unit
Function Jumper When connected When cut
(factory setting)
Fan speed setting when JB Fan speed setting ; The fan stops.
compressor stops for Remote controller setting
thermostat OFF. (effective
only in cooling operation)
Power failure recovery JC Auto-restart The unit does not resume
function operation after recovering
from a power failure. Timer
settings are cleared.
For the location of the jumper, refer to page 8, 10.
Outdoor Unit
Function Jumper When connected When cut
(factory setting)
Improvement of 20/25/35 class → J5 Standard control Reinforced control (Ex: The
defrost performance 42/50 class → J8 frequency increases, the
duration time of defrost
lengthens.)
For the location of the jumper, refer to page 12, 14.

them.

Silicon Grease on Power Transistor / Diode Bridge SiBE041434E
5. Silicon Grease on Power Transistor / Diode

Bridge
Outline Apply the specified silicon grease to the heat radiation part of a power transistor / diode bridge
when you replace an outdoor unit PCB. The silicon grease encourages the heat radiation of a
power transistor / diode bridge.
Detail 1. Wipe off the old silicon grease completely.

2. Apply the silicon grease evenly. See the illustrations below for examples of application.
3. Tighten the screws of the power transistor / diode bridge.
4. Make sure that the heat radiation parts are firmly contacted to the radiation fin.
Note: Smoke emission may be caused by bad heat radiation when the silicon grease is not
appropriately applied.
OK: Evenly applied
Power transistor
(or diode bridge)
PCB
Radiation
fin
Silicon grease (R18015)
NG: Not evenly applied
(R18016)
NG: Foreign matter is stuck.
Foreign matter (R18017)

SiBE041434E
Part 8
Appendix
1. Piping Diagrams..................................................................................117
1.1 Indoor Unit............................................................................................117
1.2 Outdoor Unit .........................................................................................119
2. Wiring Diagrams..................................................................................120
2.1 Indoor Unit............................................................................................120
2.2 Outdoor Unit .........................................................................................121
Appendix 116
Piping Diagrams SiBE041434E
1. Piping Diagrams
1.1 Indoor Unit
FTXM20/25K3V1B
Indoor unit
Heat exchanger
7.0 CuT
4.8 CuT
7.0 CuT
7.0 CuT
7.0 CuT
Thermistor (heat exchanger)
Crossflow fan
Field piping
M
(6.4 CuT) Fan motor
Field piping 9.5 CuT
(9.5 CuT)
Refrigerant flow
Cooling
Heating
4D092170
FTXM35K3V1B
Indoor unit
6.4 CuT
Heat exchanger

Crossflow fan
Field piping
M
(6.4 CuT) Fan motor
Field piping
(9.5 CuT) 9.5 CuT
Refrigerant flow
Cooling
Heating
4D092169
117 Appendix
SiBE041434E Piping Diagrams
FTXM42/50K3V1B
Indoor unit
6.4 CuT
Heat exchanger

Crossflow fan
Field piping
M
(6.4 CuT) Fan motor
Field piping
(12.7 CuT) 9.5 CuT
Refrigerant flow
Cooling
Heating
4D092168
Appendix 118
Piping Diagrams SiBE041434E
1.2 Outdoor Unit

RXM20/25/35LV1B
Outdoor unit
Heat exchanger
9.5 CuT 7.0 CuT Outdoor air temperature thermistor
7.0 CuT
Heat exchanger thermistor

Muffler with filter Electronic expansion valve
4.8 CuT 6.4 CuT 6.4 CuT EV
φ.4.0×ID.2.0 CuT
4.8 CuT Muffler with filter
M
Propeller fan
9.5 CuT
9.5 CuT
Muffler with filter
6.4 CuT
4-way valve
7.9 CuT
ON: heating Field piping

9.5 CuT
Liquid stop valve (6.4 CuT)

Muffler
Discharge pipe thermistor

Muffler
7.9 CuT
9.5 CuT 9.5 CuT Field piping

Compressor
Accumulator Muffler Gas stop valve with (9.5 CuT)
service port
Refrigerant flow
Cooling
Heating
3D092005
RXM42/50LV1B
Outdoor unit
Heat exchanger
7.9 CuT Outdoor air temperature thermistor
7.9 CuT
7.9 CuT
7.9 CuT
12.7 CuT
7.9 CuT 1-4Capillary tube

7.9 CuT 7.9 CuT 4.0 CuT 1
7.9 CuT
7.9 CuT 7.9 CuT 4.0 CuT 2
Heat exchanger thermistor 4.0 CuT 3

6.4 CuT
M 4.0 CuT 4
Muffler with filter
6.4 CuT
12.7 CuT
Propeller fan
EV 6.4 CuT
12.7 CuT Electronic expansion valve
Filter
6.4 CuT
Receiver gas
4-way valve
7.9 CuT 9.5 CuT
ON: heating 6.4 CuT Field piping

12.7 CuT
Muffler Liquid stop valve (6.4 CuT)
Muffler
Discharge pipe thermistor Muffler
9.5 CuT 9.5 CuT 9.5 CuT 12.7 CuT Field piping
7.9 CuT
Muffler Gas stop valve with (12.7 CuT)

Compressor Accumulator
service port
Refrigerant flow
Cooling
Heating
3D092010
119 Appendix
SiBE041434E Wiring Diagrams
2. Wiring Diagrams
2.1 Indoor Unit
FTXM20/25K3V1B
PCB2 S27 S26 PCB1 GRN/YLW

1 BLK 1 FG2
BLK Z1C GRN 3
Transmission circuit FG1 GRN
BLK H3 2
LED1 H1P BLK
N=3
RED 3
C101 C103 H2 1 Outdoor
LED2 BLK MR10 WHT 2
H2P BLK C102 C104 V1 H1
BLK A BLK 1
LED3 H3P BLK F1U X1M Colours
BLK 3.15A
10 BLK 10
S1W BLK : Black
t˚ WHT : White
IPM200 Indoor BRN : Brown
R1T RED : Red
GRN : Green
SR 1 3 1 2 1 5 1 6 9 12 S403 1 7 10 YLW : Yellow
S25 S32 S6 S200
ORG : Orange
WHT
BLK
ORG
YLW
BLK
BLK
BLK
BLK
BLK
BLK
BLK
BLK
BLK
BLK
RED
BLK
BLK
BLK
BLK
BLK
BLK
BLK
BLU
BLK
BLU : Blue
WRC Z2C
N=2
S36 M M
1 3 t˚ S602 S601
M1S M1F 6 1 4 1
IES
R2T
PCB3 S21 PCB4
OPTION
Field wiring
: Rectifier X1M : Terminal strip
: Protective earth MR10 : Magnetic relay
WRC : Wireless remote control V1 : Varistor
PCB1-PCB4 : Printed circuit board R1T, R2T : Thermistor
IPM200 : Intelligent power module C101-C104 : Capacitor
S6-S602 : Connector SR : Signal receiver
S1W : Operation switch IES : Intelligent Eye sensor
FG1, FG2 : Frame ground Z1C, Z2C : Ferrite core
F1U : Fuse
H1-H3 : Harness Notes : The connection of ·PCB4 ·is optional.
H1P-H3P : Pilot lamp
M1F : Fan motor
M1S : Swing motor
Caution
When the main power is turned off and then back on again, operation will resume automatically. 3D093446
FTXM35/42/50K3V1B
PCB3 S49 S46 PCB1 GRN/YLW

1 BLK 1
LED1 H1P BLK Transmission circuit FG 3
t˚ BLK GRN 2
LED2 H2P BLK H3 RED 3
RTH1 C101 H2 1 Outdoor
BLK MR10 WHT 2
LED3 H3P R1T BLK C102 V1 H1
BLK BLK 1
S1W BLK F1U X1M
9 BLK 9 A Colours
BZ 3.15A
BLK : Black
WHT : White
S21 Indoor BRN : Brown
RED : Red
GRN : Green
1 3 1 4 12 16 8 10 12 14 2 5 3 4 6 1513 11 9 7 1 1 4 7 YLW : Yellow
S47 S25 S32 S41 S1
ORG : Orange
ORG
WHT
ORG
ORG
RED
BLK
YLW
ORG
BRN
BLK
BLK
BLK
PNK
BLK
BLK
BLK
BLK
RED
BLK
RED
YLW
PNK
BLU
RED
YLW
BLU
PNK
BLU : Blue
BLU
BLU
PNK : Pink
S48 S26 MS
1 3 1 4 MSW MSW MSW 3~
t˚
SR PCB2 IES M1S M2S M3S M1F
PCB4 R2T
WRC Field wiring
: Rectifier X1M : Terminal strip

: Protective earth MR10 : Magnetic relay
WRC : Wireless remote control V1 : Varistor
PCB1-PCB4 : Printed circuit board R1T, R2T : Thermistor
BZ : Buzzer C101, C102 : Capacitor
S1-S49 : Connector SR : Signal receiver
S1W : Operation switch IES : Intelligent Eye sensor
FG : Frame ground
F1U : Fuse
H1-H3 : Harness
H1P-H3P : Pilot lamp
M1F : Fan motor
M1S-M3S : Swing motor
Caution
When the main power is turned off and then back on again, operation will resume automatically. 3D093481
Appendix 120
Wiring Diagrams SiBE041434E
2.2 Outdoor Unit

RXM20/25/35LV1B
Field wiring
Indoor
N=2 DB1 IPM1

FU3 MRM20 WHT HR2
X1M Z3C L1R +
AC1 20A L1 HR1 ~ +
1 L 1 BLK BRN
2 AC2 MRM10 +
N2 WHT V2 C5
3 S HN3 HA1 HA2 DB2 –
3 RED HN2
BLU
HL3
GRY ~ – ~ + +
V3 HL2 C119
L ORG –
MR30 FU1 V1
N +
3.15A 1 WHT 1 C6
~ – Q1
GRN/YLW
SA1 BLK –
E1 BLK –
BLK FU2
S10
GRN
S11 BLK 3.15A

BLK ~ + W V U
E2 PCB1 BLK PCB2 IPM2
BLK + –
GRN
9 BLK 9 ~ –
Z2C
RED
YLW
BLU
N=2 MRCW DB3
Outdoor
S100 S20 S80 S90 S40 S70
Q1 : Insulated Gate Bipolar Transistor(IGBT) 1 2 1 6 3 1 1 6 2 1 1 4 7 10 11 12 13 X11A
Y1E : Electronic expansion valve coil
Y1S : Reversing solenoid valve coil
BLU
RED
YLW
ORG
GRY
RED
YLW
BLU
BLU
GRY
BLK
BLK
BLK
BLK
BLK
BLK
BLK
BLK
ORG
WHT
WHT
WHT
RED
BRN
YLW
BLK
BLU
SA1 : Surge arrestor
IPM1,IPM2 : Intelligent power module X12A Z1C
X13A
Q1L : Overload protector N=4
M1C : Compressor motor Q1L
ORG
R1T R2T R3T V

RED
YLW
BLU
BLU
GRY
PCB1,PCB2,PCB3 : Printed circuit board S110 BLK Outdoor Discharge
MS W U
PCB3 3~ MS
M1F : Fan motor Condenser 3~
X1M : Terminal strip Y1S M1F
M M1C
Z1C,Z2C,Z3C : Ferrite core
L : Live Y1E
FU1,FU2,FU3 : Fuse
X11A,X12A,X13A,HA1,HL2,HR2
DB1,DB2,DB3 : Diode bridge BLK : Black
E1,E2,AC1,AC2,S,HR1,HN2 : Connection
L1 : Coil WHT : White
MRCW,MR30,MRM10,MRM20 : Magnetic relay
L1R : Reactor BRN : Brown
S10,S11,S20,S40,S70,S80,S90 RED : Red
C5,C6,C119 : Capacitor
S100,S110,HL3,HN3 : Connector GRN : Green
R1T,R2T,R3T : Thermistor
V1,V2,V3 : Varistor YLW : Yellow
N : Neutral ORG : Orange
: Protective earth
BLU : Blue
GRY : Grey 3D090516
RXM42/50LV1B
Field wiring
Indoor
Z3C FU3 IPM1
X1M N=5 30A MRM10 DB1
HL1
1
2
L 1 BLK HN1 ~+ +
+
N 2 WHT V2 ZF PAM C7
3 3 RED
S MRM20
~
V3 V1
L
N MR30 FU1
SA1
GRN/YLW
E1 3.15A FU2
PS 3.15A
GRN
Z2C
N=4 E2 W V U
PCB1
GRN
Outdoor Z1C
MRCW N=4
RED
YLW
BLU
S20 S40 S80 S90 S70

1 6 1 2 1 3 1 6 1 4 7
PS : Switching power supply
Y1E : Electronic expansion valve coil X11A
BLK
BLK
BLK
BLK
BLK
BLK
BLK
BLK
WHT
ORG
BLU
BLU
RED
YLW
WHT
ORG
BLU
Y1S : Reversing solenoid valve coil

BRN
RED
BLU
SA1 : Surge arrestor t˚ t˚ t˚

RED
YLW
BLU
IPM1 : Intelligent power module Y1S

Q1L : Overload protector M
M1C : Compressor motor Q1L R1T R2T R3T MS
V
Outdoor Discharge ~
3 W U
PCB1 : Printed circuit board Y1E MS
M1F : Fan motor
Condenser ~
3
M1F
X1M : Terminal strip M1C
Z1C, Z2C, Z3C : Ferrite core
L : Live X11A, HL1, HN1, E1, E2, S : Connection BLK : Black
FU1, FU2, FU3 : Fuse MRCW, MR30, MRM10, MRM20 : Magnetic relay WHT : White
DB1 : Diode bridge S20, S40, S70, S80, S90 : Connector BRN : Brown
N : Neutral V1, V2, V3 : Varistor RED : Red
C7 : Capacitor ZF : Noise filter GRN : Green
R1T, R2T, R3T : Thermistor : Protective earth YLW : Yellow
PAM : Pulse-amplitude modulation ORG : Orange
BLU : Blue
3D090522
121 Appendix
Revision History
Month / Year Version Revised contents
02 / 2015 SiBE041434E First edition

Warning z Daikin products are manufactured for export to numerous countries throughout the world. Prior to
purchase, please confirm with your local authorised importer, distributor and/or retailer whether this
product conforms to the applicable standards, and is suitable for use, in the region where the product
will be used. This statement does not purport to exclude, restrict or modify the application of any local
legislation.
z Ask a qualified installer or contractor to install this product. Do not try to install the product yourself.
Improper installation can result in water or refrigerant leakage, electrical shock, fire or explosion.
z Use only those parts and accessories supplied or specified by Daikin. Ask a qualified installer or
contractor to install those parts and accessories. Use of unauthorised parts and accessories or
improper installation of parts and accessories can result in water or refrigerant leakage, electrical
shock, fire or explosion.
z Read the user's manual carefully before using this product. The user's manual provides important
safety instructions and warnings. Be sure to follow these instructions and warnings.
If you have any enquiries, please contact your local importer, distributor and/or retailer.
Cautions on product corrosion

1. Air conditioners should not be installed in areas where corrosive gases, such as acid gas or alkaline gas, are produced.
2. If the outdoor unit is to be installed close to the sea shore, direct exposure to the sea breeze should be avoided. If you need to install
the outdoor unit close to the sea shore, contact your local distributor.
Dealer
Head Office:
Umeda Center Bldg., 2-4-12, Nakazaki-Nishi,
Kita-ku, Osaka, 530-8323 Japan
Tokyo Office:
JR Shinagawa East Bldg., 2-18-1, Konan,
Minato-ku, Tokyo, 108-0075 Japan
http://www.daikin.com/products/ac/
c All rights reserved
zSpecifications, designs and other content appearing in this brochure are current as of February 2015 but subject to change without notice.
SiBE041434E
02/2015 AK.B

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SiBE041434E

Part 1 List of Functions ................................................................ 1

Part 2 Specifications .................................................................... 3

Part 3 Printed Circuit Board Connector Wiring Diagram ............. 7

Part 4 Function and Control........................................................ 15

3.12 Malfunctions ...........................................................................................50

Part 5 Remote Controller ............................................................ 51

Part 6 Service Diagnosis............................................................. 56

iii Table of Contents

5.13 Power Module Check ...........................................................................106

Part 7 Trial Operation and Field Settings................................. 108

Part 8 Appendix......................................................................... 116

1.1 Warnings and Cautions Regarding Safety of Workers

When disconnecting the suction or discharge pipe of the compressor at

Be sure to discharge the capacitor completely before conducting repair

In case of R-32 / R-410A refrigerant models, be sure to use pipes, flare

Do not clean the air conditioner by splashing water.

Be sure to provide the earth / grounding when repairing the equipment in

Be sure to conduct repair work with appropriate tools.

 Checking the area

 General working area

 Checking for presence of refrigerant

 Fire extinguishing equipment

 Checking the refrigeration equipment

 Checking electrical devices

 Repairs to sealed components

 Repair to intrinsically safe components

 Leak detection methods

 Removal and evacuation

1.2 Warnings and Cautions Regarding Safety of Users

Do not damage or modify the power cable.

When replacing the coin battery in the remote controller, be sure to

Do not install the equipment in a place where there is a possibility of

If the installation platform or frame has corroded, replace it.

Do not tilt the unit when removing it.

Icon Type of Description

Note A Note provides information that is not indispensable, but may

Reference A Reference guides the reader to other places in this binder or

NIGHT QUIET mode (automatic) — — Flexible power supply correspondence — —

50 Hz, 220 - 230 - 240 V

50 Hz, 220 - 230 - 240 V

7 Printed Circuit Board Connector Wiring Diagram

Printed Circuit Board Connector Wiring Diagram 8

SW1 LED3 LED2 LED1

9 Printed Circuit Board Connector Wiring Diagram

1.2 35/42/50 Class

Printed Circuit Board Connector Wiring Diagram 10

LED3 LED2 LED1

11 Printed Circuit Board Connector Wiring Diagram

S10 J5 J4 S90 LED A

Caution Replace the PCB if you accidentally cut a wrong jumper.

Printed Circuit Board Connector Wiring Diagram 12

Filter PCB (PCB1)

 The switch SW1 has no function.

13 Printed Circuit Board Connector Wiring Diagram

2.2 42/50 Class

FU3 HL1, HN1, S

S80 S20 S40 S90 J8 J6

Caution Replace the PCB if you accidentally cut a wrong jumper.

Checking the area

General working area

Checking for presence of refrigerant

Fire extinguishing equipment

Checking the refrigeration equipment

Checking electrical devices

Repairs to sealed components

Repair to intrinsically safe components

Leak detection methods

Removal and evacuation

The switch SW1 has no function.

COMFORT The fan speed is controlled automatically.

Image of 2-area INTELLIGENT EYE