Goodman WDC063 Installation Manual

Installation, Operating and Maintenance Manual IOMM WSCWDC

Group: Chiller
Part Number: 736015417
Effective: October 1999

Supersedes: IOMM PEHPFH

The McQuay DISTINCTION SERIES 
Single/Dual Compressor Centrifugal Chillers

WSC/WDC 050, 063, 079, 087, 100, 126

© 1997 McQuay International

Table of Contents

Introduction.................................................................................................................3

General Description...........................................................................................................................................3

Application.........................................................................................................................................................3

Installation...................................................................................................................4

Receiving and Handling....................................................................................................................................4

Location and Mounting....................................................................................................................................5

Water Piping.......................................................................................................................................................6

Oil Cooler Piping................................................................................................................................................8

Refrigerant Vent Piping.....................................................................................................................................9

Electrical............................................................................................................................................................11

Power Wiring....................................................................................................................................................11

Control Wiring..................................................................................................................................................12

Prestart System Checklist...............................................................................................................................14

Operation...................................................................................................................15

Operator Responsibilities ...............................................................................................................................15

Nomenclature....................................................................................................................................................15

MicroTech Control Panel................................................................................................................................16

Capacity Control System................................................................................................................................16

Lubrication System..........................................................................................................................................19

Hot Gas Bypass................................................................................................................................................21

Maintenance..............................................................................................................22

Pressure/Temperature Chart...........................................................................................................................22

Routine Maintenance......................................................................................................................................22

Annual Shutdown............................................................................................................................................25

Annual Startup.................................................................................................................................................26

Repair of System..............................................................................................................................................26

Maintenance Schedule..............................................................................................29

Service Programs ......................................................................................................32

McQuay" is a registered trademark of McQuay International

"Illustrations cover the general appearance of McQuay International products at the time of publication and we reserve the right to make

changes in design and construction at anytime without notice"



1997 McQuay International

2 Centrifugal Chillers IOMM WSCWDC

Introduction

General Description

The McQuay Centrifugal Water Chillers are complete, self-contained, automatically controlled fluid
chilling units. Each unit is completely assembled and factory tested before shipment.

In the WSC series, each unit contains one compressor connected to a condenser and evaporator. The
WDC series are equipped with two compressors operating in parallel on a single evaporator and
condenser.

The chillers use refrigerant R-134a to reduce the size and weight of the package compared to negative
pressure refrigerants and since R-134a operates at a positive pressure over the entire operation range,
no purge system is required.

The controls are pre-wired, adjusted and tested. Only normal field connections such as piping,
electrical and pump interlocks, etc. are required thereby simplifying installation and increasing
reliability. All necessary safety and operating controls are factory installed in the control panel.

The basic sizes of units are the WSC/WDC 050, 063, 076, 079, 087, 100 and 126. They provide a
capacity range from 80 tons to 2500 tons. In this manual all references to the WSC models will equally
apply to other models unless specifically referenced otherwise.

Application

The operation and maintenance procedures presented in this manual apply to the standard
WSC/WDC family of chillers. Reference to the Installation Manual, OM 125 for these units should be
made for details pertaining to operation of the MicroTech control.

All McQuay centrifugal chillers are factory tested prior to shipment and must be initially started at the
job site by a factory trained McQuay service technician. Failure to follow this startup procedure may
affect the equipment warranty.

The standard warranty on this equipment covers parts which prove defective in material or
workmanship. Specific details of this warranty can be found in the warranty statement furnished with
the equipment.

Cooling towers used with McQuay centrifugal chillers are normally selected for maximum condenser
inlet water temperatures between 75°F and 90°F (24°C and 32°C). Lower entering water temperatures
are desirable from the standpoint of energy reduction but a minimum does exist. For recommendations
for optimum entering water temperature and cooling tower fan control, consult McQuay Product
Manual PM WSC/WDC, Applications Section.

IOMM WSCWDC Centrifugal Chillers 3

Installation

Condenser

Receiving and Handling

The unit should be inspected immediately after receipt for possible damage.
All McQuay centrifugal water chillers are shipped FOB factory and all claims for handling and

shipping damage are the responsibility of the consignee.
Insulation corners from the evaporator's rigging hole locations is shipped loose and should be glued

in place after the unit is finally placed. Neoprene vibration pads are also shipped loose. Check to be
sure that these items are delivered with the unit.

Leave the shipping skid in place until the unit is in its final position. This will aid in handling the
equipment.

Extreme care should be used when rigging the equipment to prevent damage to the control center, or
refrigerant piping. See certified dimension sheets for the center of gravity of the unit.

The unit can be lifted by fastening the rigging hooks to the four corners of the unit where the rigging
eyes are located (see Figure 1). Spreader bars should be used between the rigging lines to prevent
damage to the control center and motor terminal boxes on WDC dual compressor units.

Figure 1, Unit Components

Control Panel

Expansion Valve

Liquid Line
Shutoff Valve

Evaporator
Relief Valve

Evaporator

Condenser Dual
Relief Valves

4 Centrifugal Chillers IOMM WSCWDC

Figure 2, Major Component Location

Cooling Inlet

Eyes

Inlet (Note)

Pump, Heater

Oil Pressure Regulator

Shutoff Valve

(Duals Only)

Rigging

Eyes

Evaporator

Outlet

Evaporator

Condenser

Vent Line from Oil Sump

Suction

Outlet

Condenser

Inlet

Lubricant to Lub Control
Box for Unloader

Lubrication
Control Box

Lubricant Outlet
to Cooler

(2) Dual Relief
Values

Condenser

Oil Sump,

Discharge
Check Valve

Motor

Motor
Terminal Box

Rigging

Motor Cooling
Outlet Filter-Drier

Mounting Holes
(2) Each Corner

Note

The WDC126 Dual Compressor Chiller shown has the evaporator inlet in the bottom.

Consult unit certified drawings for connection locations on specific units.

Location and Mounting

The unit should be mounted on a level concrete or steel base and should be located so as to provide
service clearance at one end of the unit for possible removal of evaporator tubes and/or condenser
tubes. Clearances required are 18 feet (5.5 meters) for units with 16 foot (4.9 meters) long shells, 16
feet (4.9 meters) for units with 14-foot (4.3 meters) long shells, 14 feet (4.3 meters) for units with 12­foot (3.7 meters) long shells, and 10 feet (3 meters) for units with 8-foot (2.4 meters) long shells.
Evaporator/condenser tubes are rolled into the tube sheets to permit replacement if necessary.
Clearance at all other points, including the top, is 3 feet (1 meter).

The shipped loose neoprene vibration pads should be located under the corners of the unit (unless
the job specifications state otherwise).

IOMM WSCWDC Centrifugal Chillers 5

Units are shipped with refrigerant and oil valves closed to isolate these fluids for

shipment. Valves must remain closed until start-up by McQuay technician.

Water Piping

Water Pumps

Make sure that the floor or structural support is adequate to support the full operating weight of the
complete unit.

Rubber Shearflex pads, or "Isomode," are supplied with the unit for use under each corner of the base
members. The unit must be level.

It will not be necessary to bolt the unit to the mounting slab or framework; but should this be
desirable, 1 1/8" (28.5 mm) mounting holes are provided in the unit support at the four corners and
under the compressor base on the side-mounted compressor units.

Note

Avoid the use of 3600/3000 rpm (two-pole motor) pump motors.

It is not uncommon to find these pumps operate with objectionable noise and vibration.
It is also possible to build up a frequency beat due to the slight difference in the operating rpm of the

pump motor and the McQuay centrifugal motor. McQuay encourages the use of 1750/1460 rpm or
four-pole pump motors whenever possible.

Evaporator and Condenser Water Piping

All WSC and WDC evaporators and condensers come equipped with groove-type nozzles for
Victaulic couplings (also suitable for welding) or optional flange connections. The installing
contractor must provide matching mechanical connections of the sizes given in the system dimension
and capacity tables.

Important Notes on Welding

1. If welding is to be performed on the mechanical or flange connections, the solid-state temperature

sensor and thermostat bulbs must be removed from the wells to prevent damage to those
components.

2. The unit must be properly grounded or severe damage to the MicroTech Controller may occur.
Small water pressure test valves or pipe plugs are provided at both the inlets and outlets of the vessel

heads. The test valves permit the water flow pressure drops to be checked. The pressure drops and
flow rates for the various evaporators and condensers are shown in McQuay Product Manual PM
WSC/WDC. Refer to the nameplate on the vessel shell for identification.

Evaporator inlet and outlet water connections have been reversed over time with design changes in
the vessel. Be sure that water inlet and outlet connections match certified drawings and stenciled
nozzle markings. The condenser is connected with the coolest water entering at the bottom to
maximize subcooling.

Note

When common piping is used in connection with a heating system, care should be

taken to insure that water flowing through the evaporator cannot exceed 110°F which

can cause the relief valve to discharge refrigerant or damage controls.

The piping should be supported to reduce the weight and strain on the fittings and connections.
Piping should also be adequately insulated. A cleanable 20-mesh water strainer should be installed

6 Centrifugal Chillers IOMM WSCWDC

at both inlets. Sufficient shutoff valves should be installed to permit draining the water from the
evaporator or condenser without draining the complete system.

Flow Switch

A water flow switch must be mounted in either the entering or leaving water line to insure that there
will be adequate water flow to the evaporator before the unit can start. This will safeguard against
slugging the compressors on start-up. It also serves to shut down the unit in the event that water
flow is interrupted to guard against evaporator freeze-up.

A flow switch is available from McQuay under Part Number 017503300. It is a "paddle" type switch
and adaptable to any pipe size from 1 inch to 8 inches.

Consult the manufacturer's data for the minimum flow rates required to close the switch. Installation
should be as shown in Figure 3.

Figure 3, Flow Switch Mounting

Flow direction marked
on switch

I in. (25mm) NPT flow
switch connection

Tee

Electrical connections in the unit control center should be made at terminals 62 and 63. The normally
open contacts of the flow switch should be wired between these two terminals. Flow switch contact
quality must be suitable for 24 VAC, low current (16ma). Flow switch wire must be in separate conduit
from any high voltage conductors (115 VAC and higher).

CAUTION

Freeze Notice: Neither the evaporator nor the condenser is self-draining;

both must be blown out.

The piping should also include thermometers at the inlet and outlet connections and air vents at the
high points.

The water heads can be interchanged (end for end) so that the water connections can be made at
either end of the unit. If this is done, new head gaskets must be used and control sensors relocated.

In cases where the water pump noise may be objectionable, rubber isolation sections are
recommended at both the inlet and outlet of the pump. In most cases, it will not be necessary to
provide vibration eliminator sections in the condenser inlet and outlet water lines; but where noise
and vibration are critical (for example, where a pipe chase goes through walls adjoining living quarters
in an apartment building), they may be required.

Where a cooling tower is used to supply condenser water, a flow balancing valve is required. Some
form of temperature control is required if tower water becomes too cold.

IOMM WSCWDC Centrifugal Chillers 7

Oil Cooler Piping

Figure 4, Oil Cooler Water Piping Across Chilled Water Pump

Figure 5, Oil Cooler with City Water or Other Supply

WSC-048/050 and WDC-048/050 units are equipped with internal self-contained refrigerant-cooled oil
coolers and require no field piping for the coolers.

WSC 063, 079, 087, 100 and 126 single compressor units have a factory mounted water-cooled oil
cooler, a solenoid valve, and a temperature controlled water regulating valve mounted inboard of the
compressor. Accessories must be installed as shown Figure 4 or 5.

WDC 063, 079, 087, and 126 dual compressor units are equipped as above but the solenoid valves and
temperature control valve are factory installed at each cooler as standard. The water piping for the
two oil coolers cooling is factory piped to a common connection at the tube sheet.

Field water piping to the inlet and outlet connections must be installed according to good piping
practices and should include stop valves to isolate the cooler for servicing. A 1" minimum cleanable
filter (40 mesh maximum), a solenoid stop valve wired in accordance with the field connection control
diagram (also available as a factory installed option,), and drain valve or plug should also be field
installed. The water supply for the oil cooler may be either from the chilled water circuit (preferred and
recommended) or from an independent source such as city water (see Figure 5).

8 Centrifugal Chillers IOMM WSCWDC

The use of condenser water for oil cooling is not recommended. When using chilled water it is

3-Way Valve

important that the water pressure drop through the oil cooler be less than the drop across the
evaporator or insufficient oil cooler flow will result. This is normally no problem except on single pass
evaporators in which case the oil cooler water should be piped across the chilled water pump to
provide the maximum possible head and flow.

The water flow through the oil cooler will be adjusted by the regulating valve so that the temperature
of oil supplied to the compressor bearings (leaving the oil cooler) is between 80°F (27°C) and 110°F
(43°C).

When supplied with city water, the oil piping should discharge through a trap into an open drain to
prevent draining the cooler by siphoning. The discharged city water may also be used for cooling
tower makeup by discharging it into the tower sump above the highest possible water level.

Refrigerant Vent Piping

As a safety precaution, each system is equipped with pressure relief valves located on the condenser,
evaporator, and oil sump vessel for the purpose of relieving excessive refrigerant pressure to the
atmosphere. Most codes require that relief valves be vented to the outside, and this is desirable
installation practice for all installations.

Note

Remove plastic shipping plugs (if installed) from the inside of the valves prior to

making pipe connections. Whenever vent piping is installed, the lines should be run

in accordance with local code requirements; where local codes do not apply,

ANSI/ASHRAE Standard 15-1994 code recommendations should be followed.

The condenser design incorporates two relief valves (one set) with a three-way shutoff valve
separating the two valves (see Figure 6). One valve remains/in the system at all times and the second
valve acts as a standby.

If one relief valve of the two-valve set fails, the shutoff valve may be used to isolate the faulty relief
valve, while the other valve provides pressure protection.

Figure 6, Condenser Relief Valve Set

Relief Valve # 1

Stem In: # 1 Open
Stem Out: # 2 Open
Always Front or Back Seat

Relief Valve # 2

When piping the vent line to a dual valve set, it may be sized for one relief valve and piped to both
valves. On large capacity condenser designs, two separate sets of dual relief valves are used. The
vent line must be sized to the total of two valves but piped to all four.

IOMM WSCWDC Centrifugal Chillers 9

Relief Valves

0

5

.

C4820 Thru C4824 1” FPT 4

Relief valve connection sizes and quantity
are shown to the right. Relief valves must
be piped to the outside of the building in
accordance with ANSI/ASHRAE 15. Twin
relief valves mounted on a transfer valve are
used on the condenser so that one relief
valve can be shut off and removed leaving
the other in operation. Where 4 valves are

Evaporator Code Connection Number
E1608 Thru E2616 1” FPT 1
E3016 Thru E4216 1” FPT 2
E4820 Thru E4824 1” FPT 2

Condenser Code

C1608 thru C3016 1” FPT 2

C3616 Thru C4216 1” FPT 4

shown, they consist of two valves mounted
on two transfer valves. Only two relief
valves of the four are active at any time.

Vent piping is sized for only one valve of the set since only one can be in operation at a time. In no
case would a combination of evaporator and condenser sizes require more refrigerant than the
pumpdown capacity of the condenser. Condenser pumpdown capacities are based upon
ANSI/ASHRAE Standard 15 recommendations of 90% full at 90°F (32°C).

Relief Valve

Relief Valve Pipe Sizing

Relief valve pipe sizing is based on the discharge capacity for the given evaporator or condenser and
the length of piping to be run. Discharge capacity for HFC-134a vessels is calculated as follows:

C xDxL= 0 133.

Where: C=Minimum discharge capacity, lbs of air/min

D=Vessel diameter, in.
L=Vessel length, ft.

Example: E3016 Evaporator, HFC-134a Refrigerant, 75 equivalent feet of piping

C x x Lbsof air= =0133 30 16 63 8. . / min

From the table below, 75 feet of piping for 63.8 lb. of air/min. at 180 psig valve setting requires a 2"
diameter pipe.

Discharge Capacity, lbs of Air/Min

EQUIVALENT DIAMETER STANDARD WALL IRON PIPE

LENGTH OF 1” (25mm) 1.25” (32mm) 1.5” (38mm) 2” (50mm) 2.5” (64mm) 3” (76mm)

DISCHARGE RELIEF VALVE PRESSURE SETTNG

PIPING, FT. (m) 180 225 180 225 180 225 180 225 180 225 180 225

50 (15.2) 21.4 26.8 42.8 53.6 62.7 78.4 117.0 146.3 182.2 227.7 315.4 393.7

75 (22.9) 17.5 21.9 35.0 43.8 51.5 64.4 95.4 119.3 150.5 188.1 257.4 321.8
100 (30.5) 15.2 19.1 30.2 27.8 44.3 55.4 82.6 103.3 129.6 162.0 222.5 278.1
150 (45.7) 12.4 15.6 24.7 30.9 36.0 45.0 67.3 84.2 105.1 131.9 182.2 227.7
200 (61.0) 10.6 13.6 21.4 26.8 31.4 39.3 58.4 73.1 91.1 113.9 157.7 197.1
300 (91.4) 8.8 11.1 17.5 21.9 25.5 32.0 47.6 59.6 75.6 94.5 128.5 160.7

Note: Standard relief valve settings; R-134a, evaporator=180 psig, condenser=225 psig

Note: Per ASHRAE Standard 15, the pipe size may not be less than the relief device, meaning a
minimum 1" diameter pipe is required. The discharge from more than one relief valve may be run into a
common header, the area of which shall not be less than the sum of the areas of the connected pipes.
For further details, refer to ASHRAE Standard 15. The common header can be calculated by the
formula:

10 Centrifugal Chillers IOMM WSCWDC

D

Common

222 2





D D D

= +



1

. ...





n



Electrical

Wiring, fuse and wire size must be in accordance with information located in the electrical data.
Standard NEMA motor starters require modification to meet McQuay specifications. Refer to electrical
data supplied with the unit or McQuay Product Manual PM WSC/WDC.

Important: The voltage to these units should be within the limitation of +10%, and the voltage
unbalance between phases must not exceed 3%. Since a 3 1/2% voltage unbalance will cause an
approximate 25% increase in motor temperature, it is most important that the unbalance between
phases be kept at a minimum.

Power Wiring

CAUTION

Qualified and licensed electricians must perform wiring. Shock hazard exists.

Power wiring to compressors must be in proper phase sequence. Motor rotation is set up for
clockwise rotation facing lead end with phase sequence of 1-2-3. Care should be taken that proper
phase sequence is carried through the starter to compressor. With the phase sequence of 1-2-3 and
L1 connected to T1 and T6, L2 connected to T2 and T4, and L3 connected to T3 and T5, rotation is
proper. See diagram in terminal box cover.

Proper phase sequence will be determined by the McQuay start-up technician.

CAUTION

Connections to terminals must be made with copper lugs and copper wire.

Care should be taken when attaching leads to compressor terminals.

Note

Do not make final connections to motor terminals until wiring has been checked and

approved by a McQuay technician.

Under no circumstances should a compressor be brought up to speed unless proper sequence and
rotation have been established. Serious damage may result if compressor starts in wrong direction.

It is the installing contractor's responsibility to insulate the compressor motor terminals when the unit
voltage is 600 volts or greater. This is to be done after the McQuay start-up technician has checked
for proper phase sequence and motor rotation.

Following this verification by the McQuay technician, the contractor should apply the following
furnished items.

Materials required:

1. Locktite brand safety solvent (12 oz. package available as McQuay part number 350A263H72)

2. 3M Co. Scotchfil brand electrical insulation putty (available in a 60-inch roll as McQuay part

number 350A263H81)

3. 3M Co. Scotchkote brand electrical coating (available in a 15 oz. can with brush as McQuay Part

Number 350A263H16)

4. Vinyl plastic electrical tape
The above items are also available at most electrical supply outlets.

IOMM WSCWDC Centrifugal Chillers 11

Application procedure:

1. Disconnect and lock out the power source to the compressor motor.

2. Using the safety solvent, clean the motor terminals, motor barrel adjacent to the terminals, lead

lugs, and electrical cables within the terminal 4OX to remove all dirt, grime, moisture and oil.

3. Wrap the terminal with Scotchfil filling in all irregularities. The final result should be smooth and

cylindrical.

4. Doing one terminal at a time, brush the Scotchkote on the motor barrel to a distance of up to '/2"

around the terminal and, on the wrapped terminal, the rubber insulation next to the terminal and
the lug and cable for approximately 10". Wrap additional Scotchfil insulation over the
Scotchkote.

5. Tape the entire wrapped length with electrical tape to form a protective jacket.

6. Finally, brush on one more coat of Scotchkote to provide an extra moisture barrier.

Unit Mounted Starter Power Wiring

Some units are supplied with a factory wired and mounted starter equipped with ambient compensated
quick trip overloads. Wiring, fuse and wire size must be in accordance with information located in the
electrical data supplied with the unit or the electrical data pertaining to your unit.

Important: See reference above to maximum voltage unbalance limitation of 3%.
The transition timer in the starter is factory set to disconnect the star winding connection and connect

the delta winding, when the motor comes up to speed and before any speed reduction occurs.

Control Wiring

The control circuit on the McQuay WSC/WDC packaged chiller is designed for 115 volts. Power can
be supplied from a separate circuit and fused at 20 amps inductive load. If the unit is supplied with a
factory-mounted starter then the control circuit power supply is provided through a transformer
located in the starter. A free-standing starter furnished by McQuay will have a control transformer
and requires field wiring.

The disconnect switch should be tagged to prevent current interruption. Switch is to remain on at all

times in order to keep oil heaters operative and prevent refrigerant from diluting in oil.

The control center off-on switch should be turned to the "off" position at any time compressor
operation is not desired.

In the event control voltage is supplied by a transformer, the transformer should be rated at 2 KVA,
with an inrush rating of 12 KVA minimum at 80% power factor and 95% secondary voltage. For
control wire sizing, refer to N.E.C. Articles 215 and 310. In the absence of complete information to
permit calculations, the voltage drop should be physically measured. Again, the disconnect switch
should be marked to prevent control circuit from being de-energized. Water flow interlock terminals
are provided on the control center terminal strip. See field connection diagram in the Electrical Data
Section or in the cover of control center for proper connections.

The purpose of the water flow interlocks is to prevent compressor operation until such time as both
the evaporator water and condenser water pumps are running. If flow or pressure differential switches
are not furnished factory installed and wired, they must be furnished and installed by others before
the unit can be started.

WARNING

On older style units severe damage to the compressor can result if the anti-recycle

timer is turned to the "off" position and the flow switches operate intermittently.

12 Centrifugal Chillers IOMM WSCWDC

Operation of the chilled water pump may be to cycle the pump with the compressor, operate
continuously, or start automatically by a remote source. The cooling tower pump must cycle with the
machine. The holding coil of the cooling tower pump motor starter must be rated at 115 volts, 60 Hz
with a maximum volt-amperage rating of 100. If the voltage-amperage rating is exceeded, a control
relay is required.

All interlock contacts must be rated for no less than 10 inductive amps. The alarm circuit provided in
the control center utilizes 115 volts AC. The alarm used should not draw more than 10 volt amperes.

See OM 125 for MicroTech control details.

Testing Control Circuit

McQuay will test the circuits upon completion of power and control wiring during unit's initial start­up.

Surge Capacitors

All units (except those supplied with solid state starters) are supplied with surge capacitors to protect
compressor motors from electrical damage resulting from high voltage spikes. The capacitors may or
may not be wired depending upon whether or not the starter was furnished by McQuay or whether or
not it was factory mounted. Surge capacitors should be enclosed, either inside the starter (on terminal
box mounted starters) or in the compressor motor terminal box, and should be connected on the motor
terminals with leads less than 18 inches (460 mm).

IOMM WSCWDC Centrifugal Chillers 13

Prestart System Checklist

Yes No N/A

Chilled Water

Piping complete............................................................................................................................... o o o

Water system filled, vented........................................................................................................... o o o

Pumps installed, (rotation checked), strainers cleaned............................................................. o o o

Controls (3-way, face and bypass dampers, bypass valves, etc.) operable........................... o o o

Water system operated and flow balanced to meet unit design requirements ...................... o o o

Condenser Water

Cooling tower flushed, filled and vented .................................................................................... o o o

Pumps installed, (rotation checked), strainers cleaned ............................................................ o o o

Controls (3-way, bypass valves, etc.) operable ......................................................................... o o o

Water system operated and flow balanced to meet unit requirements .................................. o o o

Electrical

115 volt service completed, but not connected to control panel ............................................ o o o

Power leads connected to starter; load leads run to compressor ready for

connection when service engineer is on hand for start-up................................................... o o o

(Do not connect starter or compressor terminals)

All interlock wiring complete between control panel and complies with specifications ..... o o o

Starter complies with specifications ............................................................................................ o o o

*Oil cooler solenoid wired to control panel as shown on wiring diagram

Pump starter and interlock wired .............................................................................................. o o o

Cooling tower fans and controls wired ...................................................................................... o o o

Wiring complies with National Electrical Code and local codes ............................................. o o o

Condenser pump starting relay (CWR) installed and wired ................................................... o o o

Miscellaneous

Oil cooler water piping complete (units with water cooled oil coolers only) ........................ o o o

Relief valve piping complete ......................................................................................................... o o o

Thermometer wells, thermometers, gauges, control wells, controls, etc., installed .............. o o o

Minimum system load of 25% of machine capacity available for testing

and adjusting controls................................................................................................................. o o o

Note

This checklist must be completed and sent to the local McQuay service location

two weeks prior to start-up.

14 Centrifugal Chillers IOMM WSCWDC

Operation

Operator Responsibilities

It is important that the operator become familiar with the equipment and the system before attempting
to operate the chiller. In addition to reading this manual the operator should study operation manual
OM 125 and the control diagram furnished with the unit so that he understands the starting, operating
and shutdown sequences as well as the safety shutdown modes.

During the initial startup of the chiller the McQuay technician will be available to answer any
questions and instruct in the proper operating procedures.

It is recommended that the operator maintain an operating log for each individual chiller unit. In
addition, a separate maintenance log should be kept of the periodic maintenance and servicing
activities.

This McQuay centrifugal chiller represents a substantial investment and deserves the attention and
care normally given to keep this equipment in good working order. If the operator should encounter
abnormal or unusual operating conditions, it is recommended that a McQuay service technician be
consulted.

McQuay International conducts training for centrifugal operators at its factory Training Center
several times a year. These sessions are structured to provide basic classroom instruction and
include hands-on operating and troubleshooting exercises. For further information, contact your
McQuay representative.

Nomenclature

Each centrifugal chiller is assigned a set of identifying numbers that are used to describe the unit
features and to identify each individual unit. These number groups are stamped on each unit
nameplate.

All inquiries pertaining to operating and servicing of this unit should include all identification
numbers.

Each of the major individual components also have nameplates to provide certain necessary
information to the installer and the operator.

Compressors are designated as model CE. For example a model CE050 compressor is used on a model
WSC050 chiller unit. The compressor nameplate identifies the compressor model, style and serial
number and includes the electrical characteristics of the compressor motor. The CE050 compressor
nameplate also shows the oil pump electrical characteristics.

The condenser and evaporator vessels have nameplates stamped with the maximum working pressure
of the vessel, the National Board Number, and the vessel style number. It should be noted that the
vessel relief valve maximum settings coincides with the maximum refrigerant side vessel working
pressure.

IOMM WSCWDC Centrifugal Chillers 15

MicroTech Control Panel

The MicroTech unit controller is a microprocessor based control panel designed to initiate the step­by-step start functions of its host centrifugal compressor unit, monitor and regulate the compressors
capacity, protect it, and sequence the compressor shutdown on lack of load or in response to a preset
time. On dual compressor units, each compressor has its own controller. They are interconnected to
provide lead-lag and load-balance functions.

The full information on the features, installation, operation and problem analysis of the McQuay
microprocessor control for Centrifugal chillers, see Operators Manual OM 125. The MicroTech panel
provides a wide range of control options and data reporting and recording capability. Familiarity with
the control system is important for optimum unit operation.

Figure 7, MicroTech Control Panel

Capacity Control System

The movement of the inlet vanes, opening or closing to permit the correct quantity of refrigerant to
enter the impeller, controls the compressor capacity. The vane movement occurs in response to oil
flow from the SA or SB solenoid valves which, in turn, respond to a control module signal. This oil
flow activates a piston to rotate the vanes.

Vane Operation

The hydraulic system for the inlet guide vane capacity control operation consists of a 4-way normally
open solenoid valve located in the oil management control panel. Oil under pressure from the oil filter
is directed by the 4-way valve to either or both sides of the piston depending on whether the control
signal is to load, unload, or hold.

To open the vanes (or load the compressor) solenoid SA is de-energized and solenoid SB is
energized, allowing oil flow from port SA to one side of the piston then drain through port SB.

To close the vanes (unload compressor) valve SB is de-energized and valve SA is energized to move
the piston and vanes toward the unload position.

When both solenoid valves SA and SB are de-energized, full oil pressure is directed to both sides of
the piston through ports SA and SB, thus the vanes are held in that position. Refer to Figure 9 and
Figure 10 for solenoid action. Note that both solenoids cannot be energized simultaneously.

16 Centrifugal Chillers IOMM WSCWDC

Metering Valves

The speed at which the capacity control vanes are opened or closed can be adjusted to suit system
operating requirements. Adjustable needle valves in the oil drain lines are used to control the rate of
bleed-off and consequently the “vane speed”. These needle valves are part of the 4-way solenoid
valve assembly located in the compressor lube box (Figure 8).

The valves are normally factory set so the vanes will move from fully closed to fully opened in
approximately 3 minutes and from fully open to fully closed in 1 minute (except CE126). The speed
should be slow enough to prevent over-controlling and hunting.

Vane Speed Adjustment

The vane speed at which the capacity control vanes open or close is controlled by the rate of oil
bleed-off from the vane actuating position. This bleed-off rate is adjustable by positioning the needle
valves on SA and SB solenoid valves located in the lube box.

Screwdriver openings in the left side of the lube box permit access. The upper opening accesses the
SB needle valve for adjusting the vane OPENING speed for loading the compressor (refer to Figure 8).
Turn this screw clockwise to decrease the vane opening and counterclockwise to increase the
opening speed.

The lower opening accesses the SA needle valve for adjusting the CLOSING speed for unloading the
compressor. The same adjustment applies . . . clockwise to decrease closing, counterclockwise to
increase vane closing.

The vane speed is factory set and varies by compressor size:

Compressor Model Opening Time Closing Time

CE048 - CE050 2 - 2 1/2 min. 3/4 - 1 min.
CE063 - CE100 3 - 5 min. 1 - 2 min

CE126 5 - 8 min. 1 - 2 min.

Figure 8, Lube Box

IOMM WSCWDC Centrifugal Chillers 17

Figure 9, Vane Control Solenoid Operation

18 Centrifugal Chillers IOMM WSCWDC

Figure 10, Vane Control Solenoid Operation, Continued

Lubrication System

The lubrication system for the WSC family of units provides lubrication and heat removal for
compressor bearings and internal parts. In addition, the system provides oil under pressure to
hydraulically operate the unloading piston for positioning the inlet guide vanes for capacity control.
WDC dual compressor chillers have completely independent lubrication systems for each compressor.

Proper operation of the hydraulic system and bearing lubrication system can be assured only if
recommended oil is used, recommended oils are shown in Table 1. Each unit is factory charged with
the correct amount of the recommended oil. Under normal operation, no additional should be needed.
Oil should be visible in the oil sump sight glass at all times.

The oil pump for the CE048/050 compressor is completely self-contained within the compressor
housing. The assembly includes the pump, pump motor, oil heater and oil separator. The oil is
pumped through the oil discharge line to the oil filter in the compressor casting and then to the
internal refrigerant-cooled oil cooler.

The other compressor sizes-CE063, through CE126-utilize a separate oil pump contained in the oil
reservoir. This assembly includes pump, motor, heater and oil separator system. Oil is pumped
through the external oil cooler and then to the oil filter located inside the compressor housing.
WSC/WDC 063-126 units, single or dual compressor, utilize a water-cooled oil cooler.

The oil coolers maintain the proper oil temperature under normal operating conditions. The coolant
flow control valve should maintain 90°F-100°F (32°C-38°C). Lubrication protection for coast down in
the event of a power failure is accomplished by a spring loaded piston in models CE050 through 100.
When the oil pump is started, the piston is forced back by the oil pressure, compressing the spring

IOMM WSCWDC Centrifugal Chillers 19

and filling the piston cavity with oil. When the pump stops, the spring pressure on the piston forces
the oil out to the bearings.

In model CE126 the compressor coast down lubrication is supplied from a gravity feed oil reservoir.
A typical flow diagram is shown in Figure 11.

Table 1, Approved Polyolester Oils For R-134a Units

Compressor Models CE050 - 126
Lubricant Designation Mobil Artic EAL 46;

ICI Emkarate RL32H
McQuay Part Number
55 Gal. Drum
5 Gal. Drum
1 Gal. Can

Compressor Oil Label 070200106, Rev OB

1. Approved oil from two suppliers can be mixed.

735030432, Rev 47

735030433, Rev 47

735030435, Rev 47

(2)

20 Centrifugal Chillers IOMM WSCWDC

Figure 11, Typical Oil Flow Diagram

1. Does not apply to CE 048,050 compressors

2. Connections not necessarily in correct relative location

Hot Gas Bypass

WSC and WDC units can be equipped with an optional hot gas bypass system used to feed
discharge gas directly into the evaporator when the system load falls below 10% compressor capacity.

Light load conditions are signaled by measurement of a set percentage of RLA amps by the
MicroTech control panel. When the RLA drops to the setpoint the hot gas bypass solenoid is
energized making hot gas bypass available for use. This introduction of hot gas provides a stable
refrigerant flow and keeps the chiller from short cycling under light load conditions. It also prevents
surge during heat recovery operation.

The factory setpoint for bringing on hot gas bypass is 40% of RLA.

IOMM WSCWDC Centrifugal Chillers 21

Maintenance

Pressure/Temperature Chart

HFC-134a Temperature Pressure Chart

°F PSIG °F PSIG °F PSIG °F PSIG

6 9.7 46 41.1 86 97.0 126 187.3

8 10.8 48 43.2 88 100.6 128 192.9
10 12.0 50 45.4 90 104.3 130 198.7
12 13.2 52 47.7 92 108.1 132 204.5
14 14.4 54 50.0 94 112.0 134 210.5
16 15.7 56 52.4 96 115.9 136 216.6
18 17.1 58 54.9 98 120.0 138 222.8
20 18.4 60 57.4 100 124.1 140 229.2
22 19.9 62 60.0 102 128.4 142 235.6
24 21.3 64 62.7 104 132.7 144 242.2
26 22.9 66 65.4 106 137.2 146 249.0
28 24.5 68 68.2 108 141.7 148 255.8
30 26.1 70 71.1 110 146.3 150 262.8
32 27.8 72 74.0 112 151.1 152 270.0
34 29.5 74 77.1 114 155.9 154 277.3
36 31.3 76 80.2 116 160.9 156 284.7
38 33.1 78 83.4 118 166.0 158 292.2
40 35.0 80 86.7 120 171.1 160 299.9
42 37.0 82 90.0 122 176.4 162 307.8
44 39.0 84 93.5 124 181.8 164 315.8

Routine Maintenance

Lubrication (See Caution)

After the system is once placed into operation, no other additional oil is required except in the event
that repair work becomes necessary to the oil pump or unless a large amount of oil is lost from the
system due to a leak.

If oil must be added with the system under pressure, use a hand pump with its discharge line
connected to the service valve at the bottom of the oil pump. (The CE050 compressor with its internal
oil pump is equipped with an oil service valve on the compressor.) The POE oils used with R-134a are
hygoscopic and care should be exercised to avoid exposure to moisture (air).

Changing Oil Filters (See Caution)

McQuay chillers are at positive pressure at all times and do not leak contaminated moist air into the
refrigerant circuit eliminating the need for annual oil changes. An annual laboratory oil check is
recommended to check overall compressor condition.

22 Centrifugal Chillers IOMM WSCWDC

CE050 Compressors - If the unit is equipped with a suction line service valve (dual compressor units
are so equipped as standard), close this valve and close the valve on the motor cooling liquid line to
isolate the compressor. Remove the refrigerant from the compressor using approved procedures.
Remove the filter cover and the old filter and install the new filter, open end first. Replace the cover
using a new gasket. Reopen the suction and liquid line valves.

If the unit is not equipped with a suction line service valve, the unit will have to be pumped down in
order to remove the pressure in the compressor before removing the cover and changing the filter.
Refer to later section for pumpdown procedure.

CE063 and Larger Compressors - The oil filter in each of these machines can be changed by simply
isolating the filter cavities. Close the oil discharge line service valve at the oil pump (at the filter on
CE126). Remove the filter cover; some foaming may occur but the check valve should limit leakage
from other compressor cavities. Remove the filter , replace with new element and replace filter cover
using new gasket. Reopen the valve in pump discharge line and purge air from the oil filter cavity.

When machine is operated again, the oil level should be checked to determine if oil needs to be added
to maintain the proper operating level.

CAUTION

Improper servicing of the lubrication system,

including the addition of excessive or incorrect oil, substitute quality oil filter,

or mishandling of the equipment under pressure is hazardous.

Only authorized and trained service personnel should attempt this service.

For qualified assistance, contact your local McQuay service location.

Refrigerant Cycle

Maintenance of the refrigerant cycle consists of maintaining a log of the operating conditions, and
assuring the unit has the proper oil and refrigerant charge. (See the maintenance schedule and the
appropriate operating log at the end of this bulletin).

At every inspection, the oil, suction and discharge pressures should be noted and recorded, as well
as condenser and chiller water temperatures.

The suction line temperature at the compressor should be taken at least once a month. Subtracting
from this, the saturated temperature equivalent of the suction pressure will give the superheat.
Extreme changes in subcooling and/or superheat over a period of time will indicate losses of
refrigerant or possible deterioration of the expansion valves. Proper superheat setting is 0 to 1 degree
F (0.5 degree C) at full load. Such a small temperature difference can be hard to measure accurately.
Another method is to measure the compressor discharge superheat, the difference between the actual
discharge temperature and the saturated discharge temperature. The discharge superheat should be
between 14 and 16 degrees F (8 to 9 degrees C) at full load with R-134a refrigerant. The liquid injection
should be deactivated (remove relay #10) when taking the discharge temperature. The superheat will
increase linearly to 55 degrees F (30 degrees C) at 10% load. The Series 200 MicroTech Control can
display all superheat and subcooling temperatures.

IOMM WSCWDC Centrifugal Chillers 23

Figure 8. Typical Refrigerant Flow Diagram

1. Connection not necessarily in correct relative location.

2. Filter on dual compressor units only.

3. Liquid injection does not apply to CE 048, 050, compressors.

4. The evaporator chilled water connections are correct for WDC 126 dual compressor units only. All other models have the
chilled water inlet in the top connection.

Electrical System

Maintenance of the electrical system involves the general requirement of keeping contacts clean and
connections tight and checking on specific items as follows:

1. The compressor current draw should be checked and compared to nameplate RLA value.

Normally the actual current will be lower since the nameplate rating represents full load operation.
Also check all pump and fan motor amperages and compare with nameplate ratings.

2. Inspection should verify that the oil heaters are operative. The heaters are insert cartridge type

and can be checked by ammeter reading. They should be energized whenever power is available
to the control circuit and when the compressor is inoperative). When the compressor starts the
heaters are de-energized.

3. At least once a quarter, all safety controls except compressor overloads should be made to

operate and their operating points checked. Any control may shift its operating point as it ages,
and this must be detected so the controls can be adjusted or replaced. Pump interlocks and flow
switches should be checked to be sure they interrupt the control circuit when tripped.

4. The contactors in the motor starter should be inspected and cleaned quarterly. Tighten all

terminal connections.

5. The compressor motor resistance to ground should be checked and logged semi-annually. This

log will track insulation deterioration. A reading of 50 megohms or less indicates a possible
insulation defect or moisture and should be further checked.

24 Centrifugal Chillers IOMM WSCWDC

WARNING

Never Megger a motor while in a vacuum. Severe damage can result.

6. The centrifugal compressor must rotate in the direction indicated by the arrow on the casting near

the rotation sightglass. If the operator has any reason to suspect that the power system
connections may have been altered, (phases reversed) the compressor should be jogged to check
rotation. For assistance, call the McQuay service location.

Cleaning and Preserving

A common cause of service calls and equipment malfunction is dirt. This can be prevented with
normal maintenance. The system components most subject to dirt are:

1. Permanent or cleanable filters in the air handling equipment must be washed in accordance with

the manufacturer’s instructions; throwaway filters should be replaced. The frequency of this
service will vary with each installation.

2. Remove and clean strainers in chilled water system, oil cooler line and condenser water system at

every inspection.

Seasonal Servicing

Prior to shutdown periods and before starting up again, the following service procedures should be
completed.

Annual Shutdown

1. Where the chiller may be subject to freezing temperatures, the condenser and chiller water piping

should be disconnected and drained of all water. Dry air blown through the condenser will aid in
forcing all water out. Removal of condenser heads is also recommended. The condenser and
evaporator are not self-draining. Water permitted to remain in the piping and vessels will rupture
these parts if subjected to freezing temperature.

Forced circulation of antifreeze through the water circuits is a sure method of avoiding freeze
up.

2. Take measures to prevent the shutoff valve in the water supply line from being accidentally

turned on.

3. If a cooling tower is used and if the water pump will be exposed to freezing temperatures, be sure

to remove the pump drain plug and leave it out so any water that may accumulate will drain away.

4. Open the compressor disconnect switch, and remove the Fusetrons. If the transformer is used

for control voltage, the disconnect must remain on to provide power to the oil heater. Set the
manual stop/auto switch (SWI) to the stop position. To insure against the possibility of an
accidental start, remove the fault relay from the left side of the MicroTech panel.

5. Check for corrosion and clean and paint rusted surfaces.

6. Clean and flush water tower for all units operating on a water tower. Make sure tower

“blowdown” or bleed-off is operating. Set up and use a good maintenance program to prevent
“liming up” of both tower and condenser. It should be recognized that atmospheric air contains
many contaminants that increase the need for proper water treatment. The use of untreated water
may result in corrosion, erosion, sliming, scaling or algae formation. It is recommended that the
service of a reliable water treatment company be used. McQuay International assumes no
responsibility for the results of untreated or improperly treated water.

7. Remove condenser heads at least once a year to inspect the condenser tubes and clean if

required.

IOMM WSCWDC Centrifugal Chillers 25

Annual Startup

A dangerous condition can exist if power is applied to a faulty compressor motor starter that has been
burned out. This condition can exist without the knowledge of the person starting the equipment.

This is a good time to check all the motor winding resistance to ground. Semi-annual checking and
recording of this resistance will provide a record of any deterioration of the winding insulation. All
new units have well over 100 megohms resistance between any motor terminal and ground.

Whenever great discrepancies in readings occur or uniform readings of less than 50 megohms are
obtained, the motor cover should be removed for inspection of the winding prior to starting the unit.
Uniform readings of less than 5 megohms indicate motor failure is imminent and motor should be
replaced or repaired. Repair before failure occurs can save a great deal of time and labor expended in
the cleanup of a system after motor burnout.

1. The control circuit should be energized at all times. If the control circuit has been off and oil is

cool, energize oil heaters and allow 24 hours for heater to remove refrigerant from the oil before
starting.

2. Check and tighten all electrical connections.

3. Replace the drain plug in cooling tower pump if it was removed at shutdown time the previous

season.

4. Install Fusetrons in main disconnect switch (if removed).

5. Reconnect water lines and turn on supply water. Flush out condenser and check for leaks.

6. Refer to Manual OM 125 before energizing the compressor circuit.

Repair of System

Pressure Relief Valve Replacement

Current condenser designs use two relief valves (1 set) separated by a three way shutoff valve. This
valve allows either relief valve to be shut off, but at no time can both be shut off. In the event one of
the relief valves are leaking in the two valve set, these procedures should be followed:

• If the valve closest to the valve stem is leaking, back seat the three-way valve all the way, closing

the port to the leaking pressure relief valve. Remove and replace the faulty relief valve. The
three-way shutoff valve should remain either fully back seated or fully forward to normal
operation. If the relief valve farthest from the valve stem is leaking, front seat the three-way valve
and replace the relief valve as stated above.

• The refrigerant in the evaporator must be pumped down to the condenser to replace its relief

valve.

Pumping Down

If it becomes necessary to pump the system down, extreme care should be used to avoid damage to
the evaporator from freezing. Always make sure that full water flow is maintained through the chiller
and condenser while pumping down. To pump the system down, close all liquid line valves. With all
liquid line valves closed and water flowing, start the compressor. Set the MicroTech panel to the
manual load. The vanes must be open while pumping down to avoid a surge or other damaging
condition. Pump the unit down until the MicroTech cuts out at approximately 20 psig. It is possible
that the unit might experience a mild surge condition prior to cutout. If this should occur, immediately
shut off the compressor. Use a portable condensing unit to complete the pump down, condense the
refrigerant, and pump it into the condenser or pumpout vessel using approved procedures.

26 Centrifugal Chillers IOMM WSCWDC

A pressure regulating valve should always be used on the drum being used to build the system
pressure. Also, do not exceed the test pressure given above. When the test pressure is reached
disconnect the gas cylinder.

Pressure Testing

No pressure testing is necessary unless some damage was incurred during shipment. Damage may be
determined upon a visual inspection of the exterior piping assuring no breakage occurred or fittings
loosened. Service gauges should show a positive pressure. If no pressure is evident on the gauges,
a leak may have occurred discharging the entire refrigerant charge. In this case, the unit should be
leak tested to determine the location of the leak.

Leak Testing

In the case of loss of the entire refrigerant charge, the unit should be checked for leaks prior to
charging the complete system. This can be done by charging enough refrigerant into the system to
build the pressure up to approximately 10 psig (69 kPa) and adding sufficient dry nitrogen to bring the
pressure up to a maximum of 125 psig (860 kPa) and then leak test with an electronic leak detector.
Halide leak detectors do not function with R-134a. Water flow through the vessels should be
maintained anytime refrigerant is added or removed from the system.

CAUTION

Do not use oxygen or a mixture of R-22 and air to build up pressure as a serious

explosion can result.

A pressure regulating valve should always be used on the drum used to build up the system pressure.
Also, do not exceed the test pressure given above. When the test pressure is reached, disconnect the
gas cylinder.

If any leaks are found in welded or brazed joints or it is necessary to replace a gasket, relieve the test
pressure in the system before proceeding. For copper joints, brazing is required.

After making any necessary repair, the system should be evacuated as described in the section
following.

Evacuation

After it has been determined that there are no refrigerant leaks the system should be evacuated using
a vacuum pump with a capacity that will reduce the vacuum to at least 1000 microns of mercury.

A mercury manometer, electronic or other type of micron gauge should be connected at the farthest
point from the vacuum pump. For readings below 1000 microns, an electronic or other micron gauge
should be used.

The triple evacuation method is recommended and is particularly helpful if the vacuum pump is unable
to obtain the desired 1 millimeter of vacuum. The system is first evacuated to approximately 29 inches
of mercury. Dry nitrogen is then added to the system to bring the pressure up to zero pounds.

Then the system is once again evacuated to approximately 29 inches of mercury. This is repeated
three times. The first pulldown will remove about 90% of the noncondensables, the second about
90% of that remaining from the first pulldown and, after the third, only 1/10-1% noncondensables will
remain.

IOMM WSCWDC Centrifugal Chillers 27

Charging the System

WSC and WDC water chillers are leak tested at the factory and shipped with the correct charge of
refrigerant as indicated on the unit nameplate. In the event the refrigerant charge was lost due to
shipping damage, the system should be charged as follows after first repairing the leaks and
evacuating the system.

a. Connect the refrigerant drum to the gauge port on the liquid line shutoff valve and purge the

charging line between the refrigerant cylinder and the valve. Then open the valve to the mid­position.

b. Turn on both the cooling tower water pump and chilled water pump and allow water to circulate

through the condenser and the chiller. (It will be necessary to manually close the condenser
pump starter.)

c. If the system is under a vacuum, stand the refrigerant drum with the connection up and open the

drum and break the vacuum with refrigerant gas to a saturated pressure above freezing.

d. With a system gas pressure higher than the equivalent of a freezing temperature, invert the

charging cylinder and elevate the drum above the condenser. With the drum in this position,
valves open, water pumps operating, liquid refrigerant will flow into the condenser.
Approximately 75% of the total requirement estimated for the unit can be charged in this manner.

e. After 75% of the required charge has entered the condenser, reconnect the refrigerant drum and

charging line to the service valve on the bottom of the evaporator. Again purge the connecting
line, stand the drum with the connection up, and place the service valve in the open position.

IMPORTANT: At this point the charging position should be interrupted and prestart checks made
before attempting to complete refrigerant charge. The compressor must not be started at this time.
(Preliminary check must first be completed.)

Operation and maintenance manuals pertaining to the individual WSC or WDC unit are available from
your local McQuay representative.

Caution

It is of utmost importance that all local, national, and international regulations

concerning the handling and emission of refrigerants are observed.

28 Centrifugal Chillers IOMM WSCWDC

Maintenance Schedule

I. Compressor

A. Performance Evaluation (Log & Analysis) * O
B. Motor

• Meg. Windings X

• Ampere Balance (within 10%) X

• Terminal Check (tight conn., porcelain clean) X

• Motor Cooling (check temperature) X
C. Lubrication System

• Oil Lines Temperatures O

• Water (Refrigerant) Coolant Temperature O

• Oil Cooler Strainer (water) X

• Oil Cooler Solenoid Operation X

• Oil Analysis X

• Oil Appearance (clear color, quantity) O

• Oil Filter Change X

• Oil change if indicated by oil analysis X

D. Vane Operation

• Compressor Loads:
Operate Manual Switch X
Record Motor Amps X

• Compressor Unloads:
Operate manual Switch X
Record Motor Amps X

• Vanes Will Hold (place manual switch in "hold")
Observe Water Temp and Record Amps X
E. Internal Compressor Check X

II. Controls

A. Operating Controls

• Check Settings and Operation X

• Check Vane Control Setting and Operation X

• Verify Motor Load Limit Control X

• Verify Load Balance Operation X

• Check Oil Pump Contactor X
B. Protective Controls

• Test Operation of:
Alarm Relay X
Pump Interlocks X
Hot and Cold Oil Temperature Cutouts X
Guardistor and Surgeguard Relays X
High and Low Pressure Cutouts X
High Suction Temperature Cutout X
High Discharge Temperature Cutout X
Low Pressure Override Switch X
Oil Pump Pressure Differential Cutout X
Oil Pump Safety Timer X
Oil Pump Time Delay X
Vane Closed Switch X

IOMM WSCWDC Centrifugal Chillers 29

Key: O = Performed by in-house personnel X = Performed by McQuay Service personnel

30 Centrifugal Chillers IOMM WSCWDC

Maintenance Schedule, Cont.

III. Condenser

A. Performance Evaluation O
B. Test Water Quality X
C. Clean Condenser Tubes X
D. Eddycurrent Test - Tube Wall Thickness X
E. Seasonal Protection X

IV. Evaporator

A. Performance Evaluation (Log Conditions And Analysis O
B. Test Water Quality X
C. Clean Evaporator Tubes (as required) X
D. Eddycurrent Test - Tube Wall thickness (as required) X
E. Seasonal Protection X

V. Expansion Valves

A. Performance Evaluation (Superheat Control) X

VI. Compressor - Chiller Unit

A. Performance Evaluation O
B. Leak Test:

• Compressor Fittings and Terminal X

• Piping Fittings X

• Oil Pump Joints and Fittings X

• Vessel Relief Valves X
C. Vibration Isolation Test X
D. General Appearance:

• Paint X

• Insulation X

VII. Starter(s)

A. Examine Contactors (hardware and operation) X
B. Verify Overload Setting and Trip X
C. Test Electrical Connections X

VIII. Optional Controls

A. Hot Gas Bypass (verify operation) X
B. Liquid Injections Controls (verify operation) X

Key: O = Performed by in-house personnel X = Performed by McQuay Service personnel

Note

Some compressors use power factory correction capacitors and all have a surge

capacitor (excepting units with solid state starters). The surge capacitor may be installed

out of sight in the compressor motor terminal box. In all cases, capacitors must be

disconnected from the circuit to obtain a useful Megger reading. Failure to do so will

produce a low reading. In handling electrical components, only fully qualified

technicians should attempt service.

IOMM WSCWDC Centrifugal Chillers 31

Service Programs

It is important that an air conditioning system receive adequate maintenance if the full equipment life
and full system benefits are to be realized.

Maintenance should be an ongoing program from the time the system is initially started. A full
inspection should be made after 3 to 4 weeks of normal operation on a new installation and on a
regular basis thereafter.

McQuay offers a variety of maintenance services through the local McQuay service office, its
worldwide service organization, and can tailor these services to suit the needs of the building owner.
Most popular among these services is the McQuay Comprehensive Maintenance Contract.

For further information concerning the many services available, contact your local McQuay service
office.

32 Centrifugal Chillers IOMM WSCWDC

Post Office Box 2510, Staunton, Virginia 24402-2510 [phone] www.mcquay.com