WATER

COOLED
SCROLL
CHILLERS

WCS 50-5SP

50Hz

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MANUAL INDEX

Description Page
1.0 INTRODUCTION
1.1 Nomenclature .............................................................................................................................................................................................. 3
1.2 Physical Specifications .............................................................................................................................................................................. 4

2.0 INSTALLATION
2.1 General ......................................................................................................................................................................................................... 5
2.2 Inspection .................................................................................................................................................................................................... 5
2.3 Rigging ......................................................................................................................................................................................................... 5
2.3.1 General ........................................................................................................................................................................................... 5
2.3.2 Rigging and Moving ........................................................................................................................................................................ 5
2.4 Space Requirements and Clearance ........................................................................................................................................................ 5
2.4.1 General ........................................................................................................................................................................................... 5
2.4.2 Water Cooled Packaged Chiller ..................................................................................................................................................... 5
2.5 Foundation .................................................................................................................................................................................................. 5
2.5.1 Water Cooled Packaged Chiller ..................................................................................................................................................... 5
2.6 Vibration Isolation....................................................................................................................................................................................... 8
2.7 Piping Connection ...................................................................................................................................................................................... 9
2.7.1 Water Connections Chilled Water Piping ....................................................................................................................................... 9
2.7.2 Water Connections Multiple Packaged Chillers ............................................................................................................................. 9
2.7.2.1 Parallel Chilled Water Flow Units ................................................................................................................................... 9
2.7.2.2 Series Chilled Water Flow Units ................................................................................................................................... 10
2.7.3 Condenser Water Piping............................................................................................................................................................... 11
2.7.4 Water Quality ................................................................................................................................................................................ 11
2.8 Electrical Connections ............................................................................................................................................................................. 12
2.9 Requests for Start-Up Representative.................................................................................................................................................... 12

3.0 OPERATION
3.1 General ....................................................................................................................................................................................................... 13
3.2 Unit Piping ................................................................................................................................................................................................. 13
3.3 Water Cooled Packages Start-Up............................................................................................................................................................ 13
3.4 System Start-Up ........................................................................................................................................................................................ 13
3.5 Lubrication ................................................................................................................................................................................................ 13
3.5.1 Oil Level ........................................................................................................................................................................................ 13
3.6 System Flow Rate ..................................................................................................................................................................................... 15
3.7 System Control ......................................................................................................................................................................................... 15
3.7.1 Capacity Control ......................................................................................................................................................................... 15
3.7.2 Electrical Operating Thermostat ............................................................................................................................................... 15
3.7.2.1 General ......................................................................................................................................................................... 15

4.0 ELECTRICAL
4.1 Electrical Data ........................................................................................................................................................................................... 16
4.2 Wiring Diagram ......................................................................................................................................................................................... 17

5.0 MAINTENANCE
5.1 General ....................................................................................................................................................................................................... 18
5.2 Periodic Inspection ................................................................................................................................................................................... 18
5.3 Monthly Inspection ................................................................................................................................................................................... 18
5.4 Vessel Maintenance .................................................................................................................................................................................. 18
5.4.1 General ......................................................................................................................................................................................... 18
5.4.2 Evaporator Cleaning ..................................................................................................................................................................... 18
5.4.3 Water Cooled Condenser Cleaning .............................................................................................................................................. 18
5.4.4 Tube Replacement ....................................................................................................................................................................... 19
5.5 Electrical Malfunction ............................................................................................................................................................................... 19
5.6 Compressor Maintenance ........................................................................................................................................................................ 19
5.7 Refrigerant Charge ................................................................................................................................................................................... 19
5.7.1 General ......................................................................................................................................................................................... 19
5.8 Trouble Shooting ...................................................................................................................................................................................... 21
5.9 Sample Log Sheet ..................................................................................................................................................................................... 22
5.10 Mechanical Spare Part List ...................................................................................................................................................................... 23
5.11 Electrical Spare Part List ......................................................................................................................................................................... 24

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1.0 INTRODUCTION

This manual is designed to provide all necessary information for

installation, operation and maintenance of the latest generation of
Dunham-Bush units.

Dunham-Bush package has been manufactured under a careful

quality control system. Each packaged chiller is performance
tested at the factory at specified field operating conditions as a
final verification of reliability.

If the package is installed, operated and maintained with care and

attention according to the instructions contained herein, it will give
many years of satisfactory service.

It is assumed that the reader of this manual and those who install,
operate and maintain the equipment have a basic understanding
of the principles of air conditioning, refrigeration and electrical
controls.

1.1 NOMENCLATURE

WC S 35 - 5 S

Water Cooled DX Blank - R22

Packaged Chiller P - R407c

S - Standard
Scroll Compressor Q - Special/Custom
made

5 - 50Hz
Model Description
6 - 60Hz

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1.0 INTRODUCTION

1.2 PHYSICAL SPECIFICATIONS - U.S. CONVENTIONAL UNITS

MODEL SIZE WCS 50-5SP

COMPRESSOR

MODEL ( QTY ) ZR190KCE-TFD-425 (4)

OIL CHARGE (EACH) liters 3.25

% STEP CAPACITY 0, 25, 50, 75, 100

CRANKCASE HEATER (EACH) WATTS 90

REFRIGERANT R-407C

CONDENSER

SHELL DIAMETER INCH /MM 10 / 254

TUBE LENGTH INCH /MM (40+40) /(1016+1016)

WATER IN & OUT INCH /MM 4 / 102

EVAPORATOR

SHELL DIAMETER INCH /MM 10 / 254

TUBE LENGTH INCH /MM 84 / 2133.6

WATER IN & OUT INCH /MM 4 / 102

GENERAL

NO. OF REFRIGERANT CIRCUITS 2

SHIPPING WEIGHTS LBS /KG 3655 / 1662

OPERATING WEIGHTS LBS /KG 3965 / 1802

OPERATING CHARGE R-407C LBS /KG 116.8 / 53

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2.0 INSTALLATION

2.1 GENERAL refrigerant piping should not be used as a

ladder or as a hand hold. Do not attach a
Models WCS package chiller systems are chain hoist sling to the piping or
designed to cool water or other non-corrosive equipment. Move the unit in an upright
liquids. Water is circulated through the direct position and let it down gently from
expansion evaporator where it is cooled to the trucks or rollers.
desired temperature and then circulated to the
AHU coils for air conditioning, or to other types
of heat exchangers for process cooling. 2.3.2 RIGGING AND MOVING
Care should be taken to see that the equipment is Each unit is crated at the factory. The
properly installed and adjusted. An installer or skids on which the unit is mounted should
operator should first become familiar with the not be removed until it has reached its
information in this manual. final location. The unit can be skidded
with a forklift but care must be taken not
to damage the unit with forks. For proper
rigging see Figure 2.3
2.2 INSPECTION
When the equipment is delivered, it is important
that the following inspection be completed in the
2.4 SPACE REQUIREMENTS
presence of the carrier's representative: AND CLEARANCE
1. Check all crates and cartons received against 2.4.1 GENERAL
the Bill of Lading/Shipping Papers to be sure
they agree. The dimensional data and clearances that
follow are useful for determining space
2. Check the model number and the electrical requirements. The unit should be placed
characteristics on the nameplate to determine if to make the clearance noted available for
they are correct. servicing properly. Failure to allow these
3. Check for freight damage, shortages or other clearances will cause serious trouble and
discrepancies and note them on the delivery result in higher costs for operation,
receipt before signing. maintenance and repair.
In the event that any damage is found, a
damage claim should immediately be filed by 2.4.2 WATER COOLED PACKAGED
the purchaser against the delivering carrier as CHILLER
all shipments are made at the purchaser's risk. Space requirements and dimensional data
are shown in Figure 2.4.2. The space
requirements shown allow minimal
clearance for door opening, condenser
2.3 RIGGING cleaning and unit servicing.

2.3.1 GENERAL
Each unit has been carefully tested and 2.5 FOUNDATION
crated at the factory where every
precaution is taken to assure that the unit 2.5.1 WATER COOLED PACKAGED
reaches you in perfect condition. It is very
CHILLER
important that the riggers and movers
should use the same care and precaution A flat, level concrete foundation or floor
in moving the equipment into place. which can support the weight of the
Make sure that chains, cables, or other equipment must be provided as the unit
moving equipment are placed so as to must be level within 1/16" per ft [5.2mm
avoid damage to the unit or piping. The per meter].

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2.0 INSTALLATION

Figure 2.3 WCS50-5SP TYPICAL RIGGING

Rigging to be done in a manner so that no strain is placed on unit components other than at cable
connection points.

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2.0 INSTALLATION

FIGURE 2.4.2 WCS50-5SP DIMENSIONAL DATA

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 2.0 INSTALLATION

FIGURE 2.5.1 WCS50-5SP WEIGHT DISTRIBUTION

LOAD TOTAL
MODEL (lbs) OPERATING WGT.- (lbs)

A B C D

WCS50-5SP 871 1281 745 1068 3965

2.6 VIBRATION ISOLATION When using flexible connectors in refrigerant

piping, they must be mounted in the refrigerant
Under certain critical conditions, it may be discharge and liquid lines close to the packaged
necessary to install vibration isolators under the chiller, in a horizontal position and parallel to the
base of the Packaged Chiller. compressor crankshaft.
Rubber-in-shear or spring vibration isolators are
All piping which is external to the packaged
offered as optional items. When spring isolators
chiller must be supported by spring mounted
are used, flexible connectors must be installed in
hangers and any piping which goes through the
the water piping system and in the refrigerant
wall, ceiling or floor should be properly heathed
lines of split systems. Note: These flexible
to prevent transmission of piping vibration to the
connectors must be suitable for the fluid and
structure.
pressures involved.

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2.0 INSTALLATION

2.7 PIPING CONNECTIONS piping systems for years. Special

attention, however, must be given to the
2.7.1 WATER CONNECTIONS FOR particulars involved for each application
CHILLED WATER PIPING or serious operational problems can
After the unit has been leveled, the result. The following are guidelines
external water piping may be set up. Be which should be followed for multiple
sure water piping is connected to the unit application.
correct fittings. The water-out connection NOTE: A constant chilled water flow rate
is closest to the expansion valve (R-in) is assumed to be maintained through all
end. evaporators.
Water flow through the evaporator must
remain constant for proper chiller 2.7.2.1 Parallel Chilled Water Flow
operation. Water pressure gauges are Units
recommended to check the water pressure Method A: Both units operate
and flow rate in the system, before and simultaneously, modulating with
after the evaporator, and to determine if load variations. Each packaged
variations occur in the evaporator and chiller operating thermostat senses
system. When installing pressure taps to return water temperature using
measure the amount of pressure drop standard controls (See Figure
across the water side of the evaporator, 2.7C). The set point of each
the taps should be located in the water thermostat will be set to maintain
piping a minimum of twenty-four (24) the desired unloading. In addition
inches downstream from any connections for each chiller package, the
(flange, elbow, etc.). suction sensing hot gas by-pass
There are many piping and control valve provides modulating
systems which may be used to assure capacity reduction from 100% to
constant water flow through the approximately 30% on single
evaporator. A typical system is shown in compressor models with hot gas
Figure 2.7A. It uses a three way by-pass.
motorized valve which operates in Method B: Install units the same
response to the discharge air temperature as Method A, but add a third
of the cooling coil. thermostat in the return water, as
Another system which is sometimes used shown in Figure 2.7E. This
consists of a two way modulating control thermostat will be set to cycle off
valve, which also responds to the one of the units when the load
discharge air temperature of the cooling drops below 50%. When this
coil, used in conjunction with a spring condition is reached, leaving
loaded bypass regulating valve as shown mixed water temperature will rise,
in Figure 2.7B The bypass valve must be causing the return water
set to assure the full flow of circulating temperature to rise and the unit
chilled water when the modulating valve operating will load up. The "off"
is completely closed. unit is sequencing to start again
Other systems are noted in the ASHRAE before full system load
Handbook and may serve equally well. temperature is reached.
Whatever system is selected, water flow This system will not provide as
must be constantly maintained through stable an operation as Method A,
the chiller. but in normal air-conditioning
applications, this is not
2.7.2 WATER CONNECTIONS - Multiple detrimental. The advantage of
Packaged Chillers Method B is a better part load
Multiple unit package chillers have been efficiency and also a lead-lag
successfully applied to parallel and series control can be added.

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2.0 INSTALLATION

FIGURE 2.7A

FIGURE 2.7B

FIGURE 2.7C FIGURE 2.7D

FIGURE 2.7E
2.7.2.2 Series Chilled Water Flow
Units
Units should be equally sized. The
upstream unit will carry a larger
load because it cools higher
temperature water. The
thermostats are to sense inlet
water temperatures. (See Figure
2.7D). The number 1 unit
thermostat will unload or cycle off
the packaged chiller before
unloading occurs of the Number 2
unit.

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2.0 INSTALLATION

2.7.3 CONDENSER WATER PIPING of the condenser water temperature in the

water out pipe. For this reason, the
A relatively constant condensing
temperature sensor for the valve must be
temperature (compressor head pressure)
mounted in the water out pipe as close as
should be maintained. The supply water
possible to the condenser for minimum
temperature and flow rate must, therefore,
response time at low flow conditions.
be controlled to maintain this constant
Temperature control can also be used as
condensing temperature over the wide
an alternative for pressure control on
load and operating range of the packaged
single circuit applications.
chiller. Typical arrangements are shown
in Figure 2.7.3 valve manufacturer’s If temperature regulated water control
recommendation should be followed. valves are not used on an installation with
two condensers, manual balance valves
If city water is used, then, for economic must be installed in place of the control
reasons as well as to maintain a level valves shown in Figure 2.7.3. Adjust the
head pressure, a water regulating valve flow to provide correct condenser
should be used. This will meter only as pressure drops. Then check to insure that
much water as is necessary to maintain a leaving water temperatures are the same
given condensing temperature. One valve for both condensers while running at full
must be provided for each condenser, and load.
they should be piped as shown in Figure
If a system to be operated in a cold
2.7.3. If a cooling tower is supplying the
climate (below 32 °F [0°C] ambient),
condenser water, then some means to
some provision must be made to keep the
maintain a constant water supply
cooling tower from freezing. Consult the
temperature should be employed.
tower manufacturer for recommendations.
There are a number of different methods;
On multiple condenser systems using a
e.g. cycling the tower fan off and on single cooling tower, 2-way regulating
through a thermostat sensing the cooling valves can be used for each condenser
tower sump water; temperature dampers effectively, because usually there is
controlling air flow (may be used in sufficient water flow to the tower to
conjunction with fan cycling) or maintain efficient tower operation. See
bypassing all or part of the return water Figure 2.7.3. If automatic water regulator
directly to the sump via a 3-way valve valves are used, they should be installed
actuated by a controller sensing sump as shown. Manual hand regulating valves
temperature. may be used and installed in the same
The valve manufacturer’s recommendation location. Water flow, however, should be
for piping should be followed. Figure balanced for equal head pressure.
2.7.3 illustrates suggested water control
methods for city and tower water supply. 2.7.4 WATER QUALITY
Packages with twin circuits in one Evaporators and water cooled condensers
condenser will require control based on used in these packages are made of steel,
temperature of water out of the copper and brass and are suitable for
condenser, since condenser pressure will operation with well-maintained water
vary between the circuit. The valve must systems. However, if the water used in
be set to allow sufficient flow in the
closed position to provide measurement

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2.0 INSTALLATION

FIGURE 2.7.3

MODEL CITY 2 WAY TOWER 3 WAY TOWER

WCS50-5SP
2 PORT
N/A

evaporator or condenser circuits is corrosive, high voltage imbalance between phases must not
in mineral content or entrained solids, the water exceed 2%.
can cause reduced performance and even failure
of heat exchangers. Therefore, it may be
necessary to obtain the services of a water 2.9 REQUESTS FOR START-UP
treatment consultant and to provide and maintain REPRESENTATIVE
water treatment. This is particularly important Start-up service is an option for these units and is
with glycol systems and with cooling tower loops. requested when the unit is ordered. If start-up
service is requested, then after the installation has
been completed and checked, a one week written
notice shall be given to the Dunham-Bush
2.8 ELECTRICAL
representative. Following receipt of written
CONNECTIONS notice, a representative will be sent to the
All units are wired as completely as possible at customer. The purchaser should have competent
the factory prior to delivery. The connections service and operating personnel in attendance to
which must be made by the installer are to the assist in the work involved, and also to be trained
main power source, starting equipment and in the operation and maintenance of this unit.
interlocking the satellite equipment. In connecting The representative will inspect the installation to
power wiring to the unit, the following determine whether it meets Dunham-Bush
precautions should be taken: requirements, perform the initial start-up of the
- All field wiring is to be in accordance with the installation determine whether it is in satisfactory
National Electrical Code and state and local operating condition, and instruct specified
codes. customer personnel in its operation and
maintenance for the length of time specified in the
- All wiring is to be checked for damage and all
purchase contract.
terminal connections tested for tightness. Unit
terminal blocks are to be connected with copper NOTE: Sump oil heaters should be energized a
conductors only. Sized per ampacity listed on minimum of 24 hours and the oil sump
unit data plate. temperature must be at a minimum of 100°F
[38°C] prior to arrival of start-up representative.
- The power supply should match the unit This will ensure that the oil is warm enough to
nameplate in Volts, Phase and Hertz. Voltage vaporize any dissolved refrigerant and that the oil
must be within ±10% of nameplate value and is within the normal operating temperature range.

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3.0 OPERATION

3.1 GENERAL the motor. They must be within ±10% of the

The unit should be started up only by a nameplate voltage.
refrigeration mechanic who is familiar with 2. Start compressor(s), check the gauges and
accepted operation practices for refrigeration note if the pressures are within the prescribed
systems. limits.
Use reciprocating unit start-up report, to record all 3. Check the refrigerant sight glass to be sure it
temperature, pressure, electrical readings and is free of bubbles. If not, charge as specified
control settings. A copy must be forwarded to per section 4.8 Charging.
Dunham-Bush service department, before 4. Shut the compressor down and check the
warranty will be honored. compressor sight glass for oil level. It should
be about 1/3 of the complete sight glass. If
not, see Section 3.5 Lubrication.
3.2 UNIT PIPING 5. Restart the compressor. After an hour of
Each unit has a separate refrigerant circuit for operation the expansion valve superheat
each compressor. setting should be checked, it should be
between 10°F [5.6°C] and 15°F [8.3°C] at full
See Figures 3.2 for typical piping schematics.
load design conditions. In some instances, it
will be necessary to lower the superheat
setting to ensure proper distribution. Turn the
3.3 WATER COOLED TX valve adjustment stem clockwise to
PACKAGES START-UP increase the superheat setting and
The unit is ready for start-up when the following counterclockwise to decrease the setting. Be
procedures have been completed: sure and allow ample time between each
adjustment for the system to rebalance.
1. Water piping for the evaporator and
condenser is installed and tested. 6. The temperature of the chilled water and
condenser water (on WCS units) both in and
2. Electrical connections are made and properly
out, should be checked to insure the unit is
fused.
operating within the desired temperatures.
3. Unit has been tested for leaks, fully charged
and any leakage fixed.
4. Compressor crankcase heater(s) has been 3.5 LUBRICATION
energized for a minimum of 24 hours.
5. Calibrated refrigerant gauges have been 3.5.1 OIL LEVEL
connected to the suction and discharge A properly operated unit should run with the
pressure ports. compressor crankcase warm to touch. Check oil
6. Turn on the chilled water pump, check level frequently to see that a sufficient amount of
direction of rotation and adjust the water flow oil remains in the crankcase. Compressor oil level
through the evaporator to the specified flow can be checked by the sight glass. To make sure
rate. Bleed off all entrained air. that proper oil level is observe, operate the
7. Check if the condenser water is at the proper compressor for 15 minutes, then stop the
flow rate. Source may be from cooling tower, compressor. Oil should be about 1/3 in the sight
city or well. Bleed off all entrapped air. glass with the compressor stopped (directly after
8. Ensure all refrigerant valves are open. shutdown). At stabilized conditions with the
compressor running the oil level must be between
9. Proceed to section 3.4 systems start-up.
1/2 to 3/4 of the sight glass. Top up oil when the
compressor is running. Use the Schrader
connection at the compressor and a suitable pump
3.4 SYSTEM START-UP or any other accessible connector at the suction
1. Before starting the compressor(s), check all line.
three phases of supply voltage, of all legs of

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3.0 OPERATION
FIGURE 3.2: WCS50-5SP TYPICAL PIPING SCHEMATIC

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3.0 OPERATION
3-6 SYSTEM FLOW RATE
The quantity of chilled water or condenser water being circulated can be estimated by determining the
water pressure drop through the evaporator or condenser and reading the flow rate from the appropriate
pressure drop curve.
An alternate method of determining flow rate is to measure pressure difference from pump inlet to outlet
and read the flow rate from the pump curve.
Water flow rate must not vary more than ±10% from design flow rate.

3.7 SYSTEM CONTROL

3.7.1 CAPACITY CONTROL
The standard system capacity control operates as follows:
- As the chiller load initially drops, the suction of the compressor(s) starts dropping
proportionately, thus balancing minor load variations.
- Variation of unit capacity in response to system load requirements is controlled by an operating
temperature controller, which monitors the return water temperature.
- On multiple compressor units, capacity is controlled by a combination of compressor staging.
Refer to Table 3.7 to determine the capacity control scheme for your specific unit.

TABLE 3.7 PACKAGED CAPACITY CONTROL

COMP. UNLOADING & % UNIT CAPACITY
STAGING SCHEDULE

COMP. OFF 0

COMP. 1 ON 100% 25

COMP. 2 ON 100% 50

COMP. 3 ON 100% 75

COMP. 4 ON 100% 100

3.7.2 ELECTRONIC OPERATING THERMOSTAT

3.7.2.1 General
An electronic operating thermostat, µVision, is used on WCS packaged chiller. The
opstat senses return chilled water temperature and by staging and/or unloading
compressors is able to control leaving chilled water to a narrow band of temperature.

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3.0 OPERATION

FIGURE 3.6: WATER PRESSURE DROP

1.) EVAPORATOR

2.) CONDENSER

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4.0 ELECTRICAL

4.1 ELECTRICAL DATA

UNIT MODEL NOM. VOLTS UNIT EACH COMPRESSOR

50 HZ FLA MCA MFS RLA LRA

WCS 50-5SP 400/3/50 100A 106A 125A 25A 174A

NOTES: MCA - MINIMUM CIRCUIT AMPACITY

MFS - MAXIMUM FUSE SIZE
RLA - RATED LOAD AMPS AT ARI COS
LRA - LOCKED ROTOR AMPS

4.2 WIRING DIAGRAM When the compressor starts, the microcomputer

A copy of that diagram is furnished attached in monitors leaving water temperature using 1TS,
the unit. and condensing pressure. These inputs are used to
control the staging of the compressor.
If the safety conditions are satisfied for the #2
compressor, at least 1 minute has elapsed since
4.3 TYPICAL OPERATION
starting #1 compressor, and leaving water
In order to start a compressor; the following temperature remains above the deadband; 2M will
conditions must be met: be activated by the microcomputer, #2
- System voltage above phase control relay compressor also has a 15 minute anti-recycle
(PCR) setting (Optional) timer built into the microcomputer. Loading of
- Chilled water pump running the #2 compressor is controlled the same as
- Chilled water flow switch made compressor #1.
- Compressor circuit breakers on To shut down the unit automatically, the customer
- Customer unit control contact closed control contacts must be opened. To shut down
- Control switch and compressor switches on the unit manually, simply shut off the compressor
- Reset pressed on microcomputer keypad switches. This will causes a no-run alarm that
- Power has been on the microcomputer for 15 must be reset to restart the compressor.
minutes
- All safety conditions satisfied
- Leaving chilled water temperature 0.8°F
[0.45°C] or more above setpoint
A compressor is started by first energizing 1M.
Anti-recycle time of 5 minutes is initiated within
the computer at start.

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4.0 ELECTRICAL
FIGURE 4.2 WCS50-5SP WIRING DIAGRAM

WIRING DIAGRAM IS AS PER ATTACHED IN THE UNIT

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5.0 MAINTENANCE

5.1 GENERAL evaporator water side surfaces at least

As with all mechanical equipment, a program of annually and more often if dirtier water is
regular inspection, cleaning and preventive used. This cleaning must be done
chemically.
maintenance by trained personnel will contribute
greatly to the long satisfactory service life of this In chemical cleaning, a caustic solution is
product. pumped through the heat exchanger,
which attacks dirt, slime, and mineral
5.2 PERIODIC INSPECTION deposits and flushes them away.
Chemicals can be recommended by water
Read essential temperatures and pressures treatment specialists, but it is important to
periodically to see that they indicate normal rinse the system thoroughly after cleaning
operation. It is a good idea to record these to remove the chemicals before they
readings on a log sheet. If any abnormal operation attack the metal surfaces. The evaporator
is observed, try to remedy it. See Trouble water side (shell side) cannot be
Shooting Guide Section. physically cleaned because of the cross-
flow baffle construction.
5.3 MONTHLY INSPECTION
Check cooling tower water treatment system. 5.4.3 WATER COOLED CONDENSER
Clean external surfaces of unit. Shut unit down, CLEANING
open main disconnect, inspect control panel, The effects of fouling can be detected by
checking for loose wires, burned contacts, signs recording full load performance data on
of overheated wires, etc. Restart unit and check the log sheet. If the difference between
performance of controls. Check sight glasses for the saturated condensing temperatures
proper refrigerant charge. and the leaving condenser water
temperature is 2°F [1.1°C] greater than
5.4 VESSEL MAINTENANCE the difference recorded at clean
conditions the tubes should be cleaned. It
5.4.1 GENERAL
is generally advisable to clean the
The efficient performance of the
condenser water side surfaces at least
evaporator and condenser heat transfer
annually and more often if dirtier water is
surfaces is essential for efficient used. This cleaning can be done
performance of your packaged water chemically or physically. In chemical
cooling machine. If these surfaces cleaning, a caustic solution is pumped
accumulate a film of dirt, scale or slime, through the heat exchanger, which attacks
their performance efficiency will degrade dirt, slime and mineral deposits and
substantially. The refrigerant side of heat flushes them away. Chemicals can be
transfer surfaces does not foul since recommended by water treatment
refrigerant is a good solvent and it is in a specialists, but it is important to rinse the
closed, filtered cycle. Water side surfaces system thoroughly after cleaning to
can foul from the water system. A program remove the chemicals before they attack
of water treatment can slow the rate of the metal surfaces. Condenser tubes may
fouling on heat transfer surfaces, but not be physically cleaned by first draining the
eliminate it. condenser water, then removing the
condenser heads and brushing each tube
5.4.2 EVAPORATOR CLEANING individually with a tube cleaning brush
The effects of fouling can be detected by until it is clean. For best results, always
recording full load performance data on remove both water headers before
the log sheet. If the difference between cleaning the tubes. Replace the headers,
the leaving water from the evaporator and being careful to properly position the
saturated suction temperature at the gaskets, and refill the system with water.
compressor is 2°F [1.1°C] greater than Header gaskets need not be renewed after
the difference recorded at clean each head disassembly operation. Gaskets
conditions, the tubes should be cleaned. It
is generally advisable to clean the

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5.0 MAINTENANCE
should and must be renewed if they are At regular intervals:
physically disfigured or otherwise  Ensure the operating conditions to be always
deteriorated. (New gaskets are available within specified limit,
from the factory). INSPECT
 Make sure safety devices are operational and
CAREFULLY. properly set,
5.4.4 TUBE REPLACEMENT  Check oil level into compressor,
If your water cooled condenser ever  Check system for leaks,
experiences a tube failure, the tube can be  Clean and check operation of system heat
replaced without removing the vessel exchangers,
from its installed location (provided tube  Compressor oil quality check may include an
removal space is available). This repair acid test, humidity check and a spectrometer
can be easily be accomplished by a analysis.
serviceman skilled in tube replacement
(such as one from a boiler repair service). 5.7 REFRIGERANT CHARGE
If the condenser requiring tube 5.7.1 GENERAL
replacement is a dual refrigerant circuit All packaged chiller units are given a
vessel, special tools are required. Please complete charge of refrigerant at the
contact Topgroup M&E Services in factory. The type and amount of
Bangi, Selangor, D. E. or the nearest refrigerant required is stated in the
authorized Dunham-Bush sales Physical Specifications. The total
representative. The tubes in evaporators refrigerant shown is for the entire system.
are not replaceable. If a evaporator tube Since these units have separate circuits,
should fail, replacement vessels are each circuit should be considered
available from Dunham-Bush Industries, separately for charging.
Selangor D. E., Malaysia.
In order to check proper refrigerant
charge, look in each liquid line sight glass
5.5 ELECTRICAL with the aid of a flashlight during system
MALFUNCTION operation. At all operating conditions, the
The unit has three devices designed to protect sight glass should be clear. If bubbles are
compressor motors and manual motor controllers visible at any operating condition, the
from electrical malfunctions: Circuit breakers. circuit is short of charge.
starter overload relays, phase control relay Be careful not to overcharge the machine.
(optional). Overcharging will result in considerable
If the phase control relay trips, it is a sign of liquid logging in the condenser, and
trouble in incoming power. If it trips again after excessive condensing pressure.
resetting, call your electric utility to investigate To add refrigerant, connect a refrigerant
the problem. If circuit breaker or motor overload vessel to the 1/4" [6.4mm] charging port
relay trip, this is a sign of possible motor trouble. of the valve. Purge the air from the tube
DO NOT reset and try to run compressor again. with refrigerant gas before connecting.
Call authorized service representative to check for With the unit running, open the
motor trouble. Resetting these safety devices and refrigerant vessel vapor connection
repeated starting could turn a minor motor slightly. If the refrigerant vessel is
problem into a costly major motor burnout. warmer than the evaporator, refrigerant
will more readily flow from the vessel
5.6 COMPRESSOR into the unit.
MAINTENANCE NOTE: Only DB 02 oil may be used in this
Scroll compressors do not necessitate particular package. Use of other oil is not
maintenance. However proper operation and approved by Dunham-Bush, and will
maintenance of the system shall prevent system result in poor performance of the
related compressor problems. The following package. It is recommended to
preventive system service maintenance is change oil annually to prolong the
therefore strongly recommended: compressor life-time.

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5.0 MAINTENANCE

TABLE 5.4.2 R22 PRESSURE/TEMPERATURE PROPERTIES

Pressure Temperature Pressure Temperature Pressure Temperature

psig kPa oF oC psig kPa oF oC psig kPa oF oC

0 101.4 -41.4 -40.8 104 818.6 61.3 16.3 208 1535.9 104.1 40.1
2 115.2 -36.4 -38.0 106 832.4 62.4 16.9 210 1549.7 104.8 40.4
4 129.0 -31.8 -35.4 108 846.2 63.4 17.4 212 1563.5 105.4 40.8
6 142.8 -27.7 -33.2 110 860.0 64.4 18.0 214 1577.3 106.1 41.2
8 156.6 -23.8 -31.0 112 873.8 65.4 18.6 216 1591.0 106.7 41.5
10 170.3 -20.2 -29.0 114 887.6 66.4 19.1 218 1604.8 107.4 41.9
12 184.1 -16.9 -27.2 116 901.4 67.4 19.7 220 1618.6 108.0 42.2
14 197.9 -13.7 -25.4 118 915.2 68.3 20.2 222 1632.4 108.6 42.6
16 211.7 -10.7 -23.7 120 929.0 69.3 20.7 224 1646.2 109.3 42.9
18 225.5 -7.8 -22.1 122 942.8 70.2 21.2 226 1660.0 109.9 43.3
20 239.3 -5.1 -20.6 124 956.6 71.2 21.8 228 1673.8 110.5 43.6
22 253.1 -2.5 -19.2 126 970.4 72.1 22.3 230 1687.6 111.2 44.0
24 266.9 0.0 -17.8 128 984.1 73.0 22.8 232 1701.4 111.8 44.3
26 280.7 2.4 -16.4 130 997.9 74.0 23.3 234 1715.2 112.4 44.7
28 294.5 4.8 -15.1 132 1011.7 74.9 23.8 236 1729.0 113.0 45.0
30 308.3 7.0 -13.9 134 1025.5 75.8 24.3 238 1742.8 113.6 45.3
32 322.1 9.2 -12.7 136 1039.3 76.6 24.8 240 1756.6 114.2 45.7
34 335.9 11.3 -11.5 138 1053.1 77.5 25.3 242 1770.4 114.8 46.0
36 349.7 13.3 -10.4 140 1066.9 78.4 25.8 244 1784.2 115.4 46.3
38 363.5 15.3 -9.3 142 1080.7 79.3 26.3 246 1797.9 116.0 46.7
40 377.2 17.2 -8.2 144 1094.5 80.1 26.7 248 1811.7 116.6 47.0
42 391.0 19.1 -7.2 146 1108.3 81.0 27.2 250 1825.5 117.2 47.3
44 404.8 20.9 -6.2 148 1122.1 81.8 27.7 254 1853.1 118.3 47.9
46 418.6 22.6 -5.2 150 1135.9 82.6 28.1 258 1880.7 119.5 48.6
48 432.4 24.4 -4.2 152 1149.7 83.4 28.6 262 1908.3 120.6 49.2
50 446.2 26.1 -3.3 154 1163.5 84.3 29.1 266 1935.9 121.8 49.9
52 460.0 27.7 -2.4 156 1177.2 85.1 29.5 270 1963.5 122.9 50.5
54 473.8 29.3 -1.5 158 1191.0 85.9 29.9 274 1991.0 124.0 51.1
56 487.6 30.9 -0.6 160 1204.8 86.7 30.4 278 2018.6 125.1 51.7
58 501.4 32.4 0.2 162 1218.6 87.5 30.8 282 2046.2 126.1 52.3
60 515.2 33.9 1.1 164 1232.4 88.3 31.3 286 2073.8 127.2 52.9
62 529.0 35.4 1.9 166 1246.2 89.0 31.7 290 2101.4 128.3 53.5
64 542.8 36.9 2.7 168 1260.0 89.8 32.1 294 2129.0 129.3 54.1
66 556.6 38.3 3.5 170 1273.8 90.6 32.6 298 2156.6 130.3 54.6
68 570.3 39.7 4.3 172 1287.6 91.3 32.9 302 2184.2 131.4 55.2
70 584.1 41.0 5.0 174 1301.4 92.1 33.4 306 2211.7 132.4 55.8
72 597.9 42.4 5.8 176 1315.2 92.8 33.8 310 2239.3 133.4 56.3
74 611.7 43.7 6.5 178 1329.0 93.6 34.2 314 2266.9 134.4 56.9
76 625.5 45.0 7.2 180 1342.8 94.3 34.6 318 2294.5 135.4 57.4
78 639.3 46.3 7.9 182 1356.6 95.0 35.0 322 2322.1 136.4 58.0
80 653.1 47.5 8.6 184 1370.4 95.8 35.4 326 2349.7 137.3 58.5
82 666.9 48.7 9.3 186 1384.1 96.5 35.8 330 2377.3 138.3 59.1
84 680.7 50.0 10.0 188 1397.9 97.2 36.2 334 2404.8 139.2 59.6
86 694.5 51.2 10.7 190 1411.7 97.9 36.6 338 2432.4 140.2 60.1
88 708.3 52.3 11.3 192 1425.5 98.6 37.0 342 2460.0 141.1 60.6
90 722.1 53.5 11.9 194 1439.3 99.3 37.4 346 2487.6 142.1 61.2
92 735.9 54.6 12.6 196 1453.1 100.0 37.8 350 2515.2 143.0 61.7
94 749.7 55.8 13.2 198 1466.9 100.7 38.2 354 2542.8 143.9 62.2
96 763.5 56.9 13.8 200 1480.7 101.4 38.6 358 2570.4 144.8 62.7
98 777.2 58.0 14.4 202 1494.5 102.1 38.9 362 2597.9 145.7 63.2
100 791.0 59.1 15.1 204 1508.3 102.8 39.3 366 2625.5 146.6 63.7
102 804.8 60.3 15.7 206 1522.1 103.4 39.7 370 2653.1 147.5 64.2

NOTE : PRESSURE AND TEMPERATURE ARE STATED IN PSIA (KPA) AND °F(°C) RESPECTIVELY.

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5.0 MAINTENANCE

5.8 TROUBLE SHOOTING

SYMPTOM POSSIBLE CAUSE REMEDY

1. Unit will not 1. Power off 1. Check main disconnect switch.

start 2. Main line open 2. Check main fuses.
3. Incorrect wiring 3. Check with wiring diagrams.
4. Loose terminals 4. Tighten terminals
5. Control circuit open 5. Check pump fuses, starter heater elements,
pressure and temperature controls.

2. Compressor 1. Low voltage 1. Check at main entrance and at unit. Consult power
hums but company if voltage is low and increase wire size to
does not the unit if voltage is normal at main and low at unit.
start Voltage must be within 10% of motor nameplate
rating.
2. No power on one 2. Check fuses and wiring.
phase of 3 phase unit
3. Faulty starter or 3. Check the contacts
contactor

3. Compressor 1. Refrigerant shortage 1. Check for leaks and add refrigerant.

cycles on 2. No load on chiller 2. Check pump operation and water flow.
low pressure 3. Restriction in liquid line 3.(a.) Plugged drier. If temperature drop exists
control across the drier remove and replace cores.
(b.) Liquid line or suction valve partially closed.
Open valves fully and close in one full turn.
(c.) Expansion valve clogged or inoperative. Check
superheat setting. Check charge and thermos
bulb.
4. Head pressure too low 4. Restrict water flow to condenser by adjusting the
water regulating valve or cycle cooling tower fan.

4. Compressor 1. Compressor discharge 1. Open valve fully and close with one turn.
cycles on valve partially closed.
high 2. Air in water system 2. Flush water valve. If pressure in system exceeds
pressure the pressure corresponding to the water
control temperature purge air from compressor gauge
connection.
3. Overcharge of 3. Purge system while in operation until bubbles
refrigerant show in sight glass. Close valve and add small
amount of refrigerant until sight glass just clears.
4. High pressure control 4. Adjust the control.
improperly set
5. Dirty condenser 5. Clean condenser surfaces with brush and/or
vacuum.
6. Main water valve 6. Open the water valve.
closed
7. Water regulating valve 7. Reset or replace valve.
set high or defective
8. Water temperature too 8. Check water supply against requirement. If
high or insufficient cooling tower used, check the spray nozzles.
water

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5.0 MAINTENANCE

5.9 SAMPLE LOG SHEET SHEET NO. ................................

DUNHAM-BUSH WATER COOLED CHILLER

NAMEPLATE DATA:
UNIT MODEL NO. ....................................................... UNIT NO. ................................... VOLTS: ............................Hz ..................
UNIT SERIAL NO. ....................................................... COMPRESSOR MODEL NOS. ...................................................................
START UP : DATE ......................................... TIME ..................................................
DATE
TIME
ELAPSED TIME METERS
COMP NO.
1.
SUCTION 2.
PRESSURE 3.
4.
1.
DISCHARGE 2.
PRESSURE 3.
4.
1.
SUCTION 2.
TEMPERATURE 3.
4.
1.
DISCHARGE 2.
TEMPERATURE 3.
4.
1.
SUCTION SUPERHEAT 2.
(SUCT. TEMP.-SAT. SUCT.)* 3.
4.
1.
DISCHARGE SUPERHEAT 2.
(DISC. TEMP.-SAT. DISCH.)* 3.
4.
EVAPORATOR WATER TEMPERATURE-IN
EVAPORATOR WATER TEMPERATURE-OUT
EVAPORATOR WATER PRESSURE DROP
EVAPORATOR WATER FLOW RATE
CONDENSER WATER TEMPERATURE-IN
CONDENSER WATER TEMPERATURE-OUT
CONDENSER WATER PRESSURE DROP
CONDENSER WATER FLOW RATE
1.
COMPRESSOR AMPS 2.
3.
4.
VOLTAGES
*USE TABLE 5.7 FOR OBTAINING SATURATED TEMPERATURE
THIS LOG SHEET IS PROVIDED AS A RECOMMENDATION OF THE READINGS THAT SHOULD BE TAKEN ON A PERIODIC BASIS. THE
ACTUAL READINGS TAKEN AND THE FREQUENCY WILL DEPEND UPON THE UNITS APPLICATION, HOURS OF USE, ETC. THIS TYPE OF
INFORMATION CAN PROVE VERY USEFUL IN PREVENTING AND/ OR SOLVING PROBLEMS THAT MIGHT OCCUR DURING THE LIFE OF
THE UNIT.

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5.0 MAINTENANCE

5.10 MECHANICAL SPARE PART LIST

No Part No Description
M01a 1004015290 COM,SCRL,ZR190KCE-TFD-425
M01b 1090006147 HTR CCS 120V, 93W, 163/147
M02a 1004015290 COM,SCRL,ZR190KCE-TFD-425
M02b 1090006147 HTR CCS 120V, 93W, 163/147
M03 3003450015 PRV,SFA22,450PSI,3/4"MNPT*FNPT
M04 3012120013 VAL,ANG 0.500FL*0.38MPT(CHINA)
M05 3012140010 VAL,ANG 7/8"*7/8"ODS
M06 3012140010 VAL,ANG 7/8"*7/8"ODS
M07 3204107043 DRI-SHL 487,7/8,1-BLK
M08 3204107043 DRI-SHL 487,7/8,1-BLK
M09 3204904015 DRI-CRE 4-DM (POE OIL)
M10 3012140010 VAL,ANG 7/8"*7/8"ODS
M11 3012140010 VAL,ANG 7/8"*7/8"ODS
M12 3005020002 VAL-SOL 7/8 ODF HV20M7T 110V
M13 3005020002 VAL-SOL 7/8 ODF HV20M7T 110V
M14 3201114041 SIGHT GLASS 7/8" ODF SGP 22sN
M15 3201114041 SIGHT GLASS 7/8" ODF SGP 22sN
M16 3001270252 TXV TGEZ 27, 7/8' X 1 3/8"
M17 3001270252 TXV TGEZ 27, 7/8' X 1 3/8"
M18 3201114041 SIGHT GLASS 7/8" ODF SGP 22sN
M19 3201114041 SIGHT GLASS 7/8" ODF SGP 22sN
Oil 7101002015 OIL, DHB-015
Ref 7102407004 RFG-R407C

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5.0 MAINTENANCE

5.11 ELECTRICAL SPARE PART LIST

Part Number Description Qty UM

4005006001 FUS-HRC, 6A 3 EA
4005010004 FUS-HRC, 10A 1 EA
4011042016 FUS HLD UMS 32A 4 EA
4008416031 TSF 380/400/415V-115V 0.5KVA 1 EA
4017332358 MCB 3P 32A 10kA S203M-K ABB 4 EA
4001140334 CTR-3TS-40A (110V) 1NO 1NC 4 EA
4009036213 OL (25A - 36A) 4 EA
4010460052 460L-DB 3-PH V MNT (UL/CE) 1 EA
4001114005 AUX CONT (1NO) 4 EA
4003101039 IDR LT-RED/110V, AD22B-22D6RS 5 EA
4003104040 IDR LT-GRN/110V, AD22B-22D6GS 4 EA
4003105041 IDR LT-WHT/110V, AD22B-22D6WS 1 EA
4030001682 FUSE 5A ABC-5 1 EA
4005010048 FUS-ABC-10-R, 10A 1 EA
4006108002 RLY 110VAC 8 PINS C/W BASE 2 EA
4007101024 ROCKER SWT-15A 5 EA
4007402037 ISO-1P/CA10-A210-E24 (R/O/L) 1 EA
4008214180 TSF-115-24VAC, 100VA 1 EA
4030003016 CONTROLLER DBµ MEDIUM 1 EA
4030004379 CONNECTOR DBµ MEDIUM 1 EA
4030003017 DBGE DISP PNL MOUNTED 1 EA
4030005050 P.TRM 0/200PSI,4-20mA(DBM) 2 EA
4030005051 P.TRM 0/500PSI,4-20mA(DBM) 2 EA
4030007700 TMP SEN 6M NTC060WF-50-105C UL 1 EA
4030008001 RES 51 OHM, 5W, 5% 4 EA
4030008068 RES-10K 2W[H003008A1] 1 EA
4011011018 FUS HLD 10A 1P 1 EA

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- 27 -