McQuay WHS 155A Installation Manual

Installation, Operation and Maintenance Manual IOMM WHS

Water-Cooled Screw Compressor Chiller

WHS 155A - WHS 200A, R-22
WHS 220A, R-410A
60 Hertz

Group: Chiller
Part Number:746462
Effective: November 1998

Supersedes: IM 692-1

© 1997 McQuay International

Table of Contents

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

Receiving and Handling...............................................................................................................................3

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

Location and Mounting....................................................................................................................................4

Compressor Condensation...............................................................................................................................4

Vibration Isolators..............................................................................................................................................4

Evaporator and Condenser Water Piping.......................................................................................................7

Water Treatment.................................................................................................................................................7

Head Pressure Control, Tower System...........................................................................................................7

Head Pressure Control, Well Water System ...................................................................................................8

Relief Valve Piping.............................................................................................................................................8

Temperature and Water Flow Limitations.......................................................................................................9

Startup With Cold Condenser Water..............................................................................................................9

Evaporator Freeze Protection...........................................................................................................................9

Condenser Protection and Design Considerations......................................................................................9

Chilled Water Thermostat.................................................................................................................................9

Refrigerant Charge...........................................................................................................................................10

Detection of Loss of Flow..............................................................................................................................10

Glycol Solutions...............................................................................................................................................10

Chilled Water Quantity....................................................................................................................................11

Evaporator and Condenser Water Flow and Pressure Drop...................................12

Physical Data.............................................................................................................16

Dimensional Data......................................................................................................18

Field Wiring...............................................................................................................22

General Information.....................................................................................................................................22

Pre-Start-up...............................................................................................................26

Sequence of Operation..............................................................................................26

Initial Conditions..............................................................................................................................................26

Off Conditions..................................................................................................................................................27

Alarm..................................................................................................................................................................27

Initial Start-up...................................................................................................................................................27

Load Recycle ....................................................................................................................................................28

Maintenance..............................................................................................................28

General..........................................................................................................................................................28

Compressor Maintenance..........................................................................................................................28

Lubrication...................................................................................................................................................28

Electrical Terminals......................................................................................................................................29

Condensers ..................................................................................................................................................29

Refrigerant Sightglass................................................................................................................................29

Lead-Lag.......................................................................................................................................................29

Preventative Maintenance Schedule ............................................................................................................30

"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 WHS 155A- 220A IOMM WHS

Introduction

McQuay StarGate™ water-cooled chillers are completely assembled, factory wired, evacuated,
charged, tested and ready for installation. Each unit consists of a water-cooled condenser with
integral subcooler, dual accessible semi-hermetic single screw compressors with suction and
discharge shutoff valves, replaceable tube shell-and-tube evaporator, and complete refrigerant piping.
Liquid line components included are manual liquid line shutoff valves, charging valves, filter-dryers,
liquid line solenoid valves, sightglass/moisture indicators, and electronic expansion valves. Other
features include compressor heaters, and an advanced fully integrated microprocessor control system.

The electrical control center includes all safety and operating controls necessary for dependable
automatic operation, (the high and low pressure controls are external from the electrical control
center). Compressors are protected by solid-state overload protection and over temperature
protection.

Receiving and Handling

Inspect the unit immediately after receipt for possible damage. The unit is shipped FOB factory and all
claims for handling and shipping damage are the responsibility of the consignee. Leave the shipping
skid in place until the unit is in final position. This will aid in handling the equipment. Use extreme
care when rigging the equipment to prevent damage to the control center, or refrigerant piping. See
Dimensional Data for the center of gravity of the unit.

Lift the unit by fastening the rigging hooks to the four corners of the evaporator where the rigging
eyes are located (see Figure 1). Use spreader bars between the rigging lines to prevent damage to the
control center.

Figure 1, Rigging Eyes

Rigging Eyes

Rigging Eyes

IOMM WHS WHS 155A - 220A 3

Installation

CAUTION

Installation must be performed by qualified personnel who are familiar with local codes,
regulations, and experienced with this type of equipment.

Start-up by McQuayService is included on all units sold for installation within North America
excluding Mexico. Two weeks prior notification of start-up is required. The contractor should obtain
a copy of the Start-up Scheduled Request Form from the sales representative or from the nearest
McQuayService office.

Location and Mounting

Mount the unit on level concrete or steel base. Service and tube pull clearance (at either end of the
unit) is 14 feet (4.3 m). Evaporator and condenser tubes are rolled into the tube sheets to permit
replacement. Clearance at the sides and other end, including the top, is 3 feet (1 m).

Make certain the floor or structural support is adequate to support the full operating weight of the
complete unit. Optional rubber-in-shear pads, or spring isolators can be ordered for use under each
corner of the base members. It is not necessary to bolt the unit to the mounting slab or frame work;
although mounting holes are provided in the unit support at the four corners.

Compressor Condensation

Condensation occurs on the compressor surface when the temperature of the compressor surface is
lower than the ambient dew point temperature. Drain pans with drain connections are provided
underneath each compressor to collect the condensate. The compressor motor housing extends past
the drain pans. Install a floor drain close to the unit to collect condensate from motor housing and
condensate pans.

Vibration Isolators

Waffle type vibration isolator pads are shipped with the unit for field installation. These pads provide
minimal isolation. Vibration isolators are recommended on all upper level installations where vibration
transmission is a consideration. When vibration isolators are used, install springs under the main unit
supports. Adjust spring so the upper housing clears lower housing by at least 1/4” (6mm) and not
more than 1/2” (13mm). If hold-down bolts are not used, install a rubber anti-skid under isolators.
Install vibration eliminators in water piping to reduce piping strain, vibration, and noise. Table 1 lists
spring and rubber-in-shear isolators for all WHS unit sizes.

4 WHS 155A- 220A IOMM WHS

Table 1, Vibration Isolators (WHS 155A - 200A)

Isolator Isolator Per Location

1 2 3 4

Rubber-in-Shear RP-4 RP-4 RP-4 RP-4

Spring CP-4-28 CP-4-28 CP-4-28 CP-4-28

Figure 2, Isolator location

Table 2, Isolators (WHS 220A)

Color Recom.

Isolator Type Of McQuay Max Ld

Stripe Part No. Lb. (Kg)

Rubber-In-Shear RP-4 Green 0021639803 3300 (1497)

Spring CP-4-28 Green 0058051328 3600 (1633)

Note: The spring is fully compressed at about 5400 lb (2449 Kg).

Figure 3 and Figure 4 give dimensions required to secure each McQuay isolator section to the
mounting surface. The maximum loads for each unit are shown in Table 3.

Figure 3 , Rubber-in-Shear Isolator

IOMM WHS WHS 155A - 220A 5

Figure 4, Spring Flex Isolator

Table 3, Corner Weights for Standard Shell Units lb (kg)

WHS Unit U X V W

155-200 2105 (953) 2475 (1121) 2477 (1122) 2913 (1320)

220 2564 (1161) 3060 (1386) 2935 (1330) 3501 (1586)

Figure 5, Corner Weight Locations

6 WHS 155A- 220A IOMM WHS

Evaporator and Condenser Water Piping

WHS evaporators and condensers are equipped with either victaulic or flange connections. The
installing contractor must provide matching connections.

CAUTION

Remove the solid-state temperature sensor and thermostat bulbs from the wells to prevent
damage to those components when welding on the victaulic or flange connections.

Connect the condenser with the inlet water entering at the bottom to maximize subcooling. The
condenser water will discharge from the top connection.

Support piping to reduce weight and strain on the fittings and connections. Be sure piping is
adequately insulated. Install a cleanable 20-mesh water strainer in evaporator and condenser water
piping. Install enough shutoff valves to permit draining water from the evaporator or condenser
without draining the complete system.

CAUTION

Freeze Notice: The evaporator and condenser are not self-draining. Both must be blown out.

Include thermometers at the inlet and outlet connections and air vents at the high points of piping.
The water heads can be interchanged (end for end) allowing water connections to be made at either
end of the unit. Use new head gaskets when interchanging water heads. When water pump noise is
objectionable, use rubber isolation sections at both the inlet and outlet of the pump. Vibration
eliminator sections in the condenser inlet and outlet water lines are not normally required. Where
noise and vibration are critical, and unit is mounted on spring isolators, flexible piping connections are
necessary.

Water Treatment

If unit is operating with a cooling tower, clean and flush cooling tower. Make sure tower "blowdown"
or bleedoff is operating. Atmospheric air contains many contaminants which increases the need for
water treatment. The use of untreated water may result in corrosion, erosion, sliming, scaling, or algae
formation. A water treatment service is recommended. McQuay International is not responsible for
damage or faulty operation from untreated or improperly treated water.

Head Pressure Control, Tower System

The minimum entering water temperature to the condenser must not be lower than 75°F (23.9°C) at full
tower water flow. If lower temperature water is used, the flow must be reduced proportionally. Use a
three-way bypass valve around the tower to modulate the condenser water flow. Figure 6 shows a
three-way pressure actuator water regulating valve used for cooling applications. This regulating
valve will assure an adequate condensing pressure if the inlet condenser water temperature falls below
75°F (23.9°C). An optional AOX-4 board located in the MicroTech panel will control a cooling tower
bypass valve or a variable speed condenser pump.

IOMM WHS WHS 155A - 220A 7

Head Pressure Control, Well Water System

When using city or well water for condensing refrigerant, install a normally closed direct acting water
regulating valve in the outlet piping of the condenser. This regulating valve will assure an adequate
condensing pressure if the inlet condenser water temperature falls below 75°F (23.9°C). The
condenser service valve provides a pressure tap for the regulating valve. The valve can modulate in
response to head pressure. On shutdown, the valve closes, preventing water from siphoning out of
the condenser. Siphoning causes condenser waterside drying and accelerates fouling. If a valve is
not used, Figure 7 illustrates the recommendation of a loop at the outlet. Size the loop height (H) to
offset the negative pressure caused by the siphoning effect. A vacuum breaker may be required.

Figure 6, Bypass valve

Figure 7, Well Water System

Relief Valve Piping

Follow the requirements of ANSI/ASHRAE Standard 15-1994 for relief valve piping. The condenser
relief valve assembly consists of a tree valve and two relief valves. The tree valve must be fully front
or back seated to ensure only one relief valve is available for discharge.

8 WHS 155A- 220A IOMM WHS

Temperature and Water Flow Limitations

WHS units are designed to operate in conditions from 20°F (-6.7°C) to 50°F (10°C) leaving water
temperature on the evaporator side and 75°F (23.9°C) to 95°F (35°C) entering water temperature on the
condenser side.

Glycol in the evaporator is required on all applications below 40°F (4.4°C) leaving evaporator fluid
temperature. The maximum allowable water temperature to the cooler in a non-operating cycle is 105°F
(40.6°C). The non-operating leaving condenser water temperature maximum is 115°F (46.1°C). Flow
rates below the minimum values shown in the evaporator and condenser pressure drop curves may
cause freeze-up problems, scaling and poor control. Flow rates above the maximum values shown in
the evaporator and condenser pressure drop curves will result in unacceptable pressure drops,
excessive nozzle and tube erosion and possibly cause tube failure.

Startup With Cold Condenser Water

WHS screw compressor chillers are designed to permit startup with elevated chilled water
temperatures and cold condenser water. Following a weekend shutdown, for example, in relatively
cool, low wet bulb ambient, the building chilled water temperature could be 70°F to 80°F (21°C to 27°C)
with a condenser water temperature of 55°F (13°C). Start up under these conditions is expected. If the
cooling load is excessive, or condenser water temperatures substantially less, modification of alarm
timer settings by the McQuayService Technician may be required.

Evaporator Freeze Protection

When freeze protection is a concern, do the following:

1. If the unit will not be operated during the winter, drain and flush the evaporator and chilled water

piping with glycol. Drain and vent connections are provided on the evaporator.

2. When using a cooling tower, add glycol solution to the chilled water system. Freeze point should

be approximately 10°F (5.6°C) below minimum design ambient temperature.

Note: Freeze damage is not considered a warranty failure and is not the responsibility of
McQuay International.

3. Insulate field water piping, especially on the chilled water side.

Condenser Protection and Design Considerations

If pond or river water is used as a condensing medium and the water valves leak, the condenser and
liquid line refrigerant temperature could drop below the equipment room temperature on the "off"
cycle. This problem occurs when cold water continues to circulate through the condenser and the
unit remains off due to satisfied cooling load. If this occurs:

1. Cycle the condenser pump off with the unit.

2. Verify the liquid line solenoid valves are operating properly.

Chilled Water Thermostat

The WHS water-cooled chiller is equipped with the MicroTech leaving water controller. Be careful
when working around the unit to avoid damaging lead wires and sensor cables. Check lead wires
before running the unit. Avoid rubbing the lead wires on the frame or other components. Verify the
lead wires are firmly anchored. If the sensor is removed from the well for servicing, do not wipe off the
heat conducting compound supplied in the well.

IOMM WHS WHS 155A - 220A 9

Refrigerant Charge

All units are designed for use with R-22 or R-410A and are shipped with a full operating charge. The
operating charge for each unit is shown in the Physical Data Table.

Detection of Loss of Flow

NOTE: Water pressure differential switches are not recommended for outdoor applications.

The preferred means for detecting loss of flow is the use of factory-mounted pressure differential
switches for the evaporator and condenser.

A flow switch is available from McQuay (part number 00175033-00). It is a “paddle” type switch and
adaptable to any pipe size from 3” (76mm) to 8” (203mm) nominal. Two flow switches are required.
Mount the flow switch in either the entering or leaving water line of the evaporator and condenser.
Certain minimum flow rates are required to close the switch and are listed in Table 4. Installation
should be as shown in Figure 8.

Figure 8, Flow Switch

Connect the normally open contacts of the flow switch in the unit control center at terminals 62 and

63. Flow switch contact must be suitable for 24 VAC, low current (16ma).

Table 4, Flow Switch Minimum Flow Rates

Nominal Pipe Size Min. Required Flow to

(inches) Activate Switch - GPM (L/s)

5 58.7 (3.7)
6 79.2 (5)

Glycol Solutions

A glycol anti-freeze solution is required for operation below 40°F leaving chilled fluid temperature.
The introduction of a glycol solution reduces the capacity of the chiller and any air handling
equipment. Contact the local McQuay sales office for determination of the affect of glycol on the
chiller capacity, power input and pressure drop.

CAUTION

Use industrial grade glycols only. Do not use an automotive grade antifreeze. Automotive
antifreeze contains inhibitors that will cause plating on the copper tubes within the chiller
evaporator. The type and handling of glycol used must be consistent with local codes.

10 WHS 155A- 220A IOMM WHS

Chilled Water Quantity

All chillers need adequate time to recognize a load change, respond to the load change and stabilize
without short-cycling the compressor. There is a distinct relationship between the minimum capacity
of the chiller plant, the system minimum expected capacity, system water volume, the desired interval
between starts, and the dead band of the chiller controller-the number of degrees between shut off
and turn on. McQuay centrifugal chillers unload to 10% (5% for dual compressor units), have as little
as 20 minutes between starts (adjustable from 60 to 20 minutes), and a factory default value of 6
degrees F of chilled water temperature between shut off and restart (adjustable 2 to 20°F). There must
be sufficient time/volume when the compressor is running with more capacity than system load, plus
sufficient time/volume for the compressor to be off during the required anti-cycle time. These
relationships are expressed in the following formula:

V

=

720






Where: V = Total system U.S. gallons TS = Time between starts (min)

TD = Dead band range of controller (°F)
H2 = Minimum system capacity (btu/hr) H1 = Chiller minimum capacity (btu/hr)

TS

TD



+



H H



−

1 2 2

TD













H

IOMM WHS WHS 155A - 220A 11

Evaporator and Condenser Water Flow and Pressure Drop

Important Note

Flow rates must fall between the minimum and maximum values shown on the appropriate evaporator
and condenser curves. Flow rates below the minimum values shown will result in laminar flow that will
reduce efficiency, cause erratic operation of the electronic expansion valve and could cause low
temperature cutouts. Flow rates exceeding the maximum values shown can cause erosion on the
evaporator water connections and tubes.

Measure the chilled water pressure drop through the evaporator at field installed pressure taps. It is
important not to include the effect of valves or strainers in these readings.

Do not vary the water flow through the evaporator while the compressor(s) are operating. MicroTech
control setpoints are based on constant flow.

Figure 9, Evaporator 2-Pass

12 WHS 155A- 220A IOMM WHS

Figure 10, Evaporator, 3-Pass

IOMM WHS WHS 155A - 220A 13

Figure 11, Condenser 2-Pass

14 WHS 155A- 220A IOMM WHS

Figure 12, Condenser, 3-Pass

IOMM WHS WHS 155A - 220A 15

Physical Data

Table 5, Physical Data, WHS 155A - WHS 180A

BASIC DATA

Unit Capacity @ ARI Conditions,

tons (kW)
Refrigerant HCFC-22 HCFC-22 HCFC-22
Unit Operating Charge, lb. (kg) 661 (300) 653 (296) 653 (296)
Min Pumpdown Capacity, lb. (kg) 882 (400) 822 (373) 822 (373)
Cabinet Dimensions 162.7 x 42 x 76.9 162.7 x 42 x 76.9 162.7 x 42 x 76.9
L x W x H, in. (mm) 4134 x 1067 x 1953 4134 x 1067 x 1953 4134 x 1067 x 1953
Operating Weight (with

starters),lb.(kg)
Shipping Weight, (with
starters),lb.(kg)

COMPRESSORS, SCREW, SEMI-HERMETIC

Nominal Tons, (kW) 70 (250) 70 (250) 70 (250) 85 (300) 85 (300) 85 (300)

FLOODED EVAPORATOR

Quantity, (Number of Water
Passes)
Shell Diameter – Tube Length 18 - 12 18 - 12 18 - 12
in. - ft. (mm - mm) (457 - 3658) (457 - 3658) (457 - 3658)
Water Volume, gallons (L) 42 (160) 42 (160) 42 (160)
Max. Water Pressure, psi (kPa) 150 (1035) 150 (1035) 150 (1035)
Max. Refrigerant Pressure, psi
(kPa)
Water Connections (Victaulic), in
(mm)

CONDENSER

Quantity, (Number of Water
Passes)
Shell Diameter -- Tube Length 18 - 12 18 - 12 18 - 12
in. - ft. (mm - mm) (457 - 3658) (457 - 3658) (457 - 3658)
Water Volume, gallons (L) 45.2 (171) 51.6 (196) 51.6 (196)
Max. Water Pressure, psi (kPa) 150 (1035) 150 (1035) 150 (1035)
Max. Refrigerant Pressure, psi
(kPa)
Water Connections (Victaulic), in
(mm)

Data 155A 170A 180A

148.3 (519) 163.8 (573) 178.2 (624)

9970 (4522) 9970 (4522) 9970 (4522)

9567 (4339) 9567 (4339) 9567 (4339)

1 (1,2,3) 1 (1,2,3) 1 (1,2,3)

250 (1725) 250 (1725) 250 (1725)

6 (152) 6 (152) 6 (152)

1 (2,3) 1 (2,3) 1 (2,3)

300 (2070) 300 (2070) 300 (2070)

6 (152) 6 (152) 6 (152)

16 WHS 155A- 220A IOMM WHS

Table 6, Physical Data, WHS 190A - WHS 220A

DAta 190A 200A 220A

BASIC DATA

Unit Capacity @ ARI Conditions,
tons (kW)
Refrigerant HCFC-22 HCFC-22 HFC-410A
Unit Operating Charge, lb. (kg) 653 (296) 653 (296) 857 (389)
Min Pumpdown Capacity, lb. (kg) 822 (373) 822 (373) 915 (415)
Cabinet Dimensions 162.7 x 42 x 76.9 162.7 x 42 x 76.9 163.7 x 43.9 x 84.2
L x W x H, in. (mm) 4134 x 1067 x 1953 4134 x 1067 x 1953 4159 x 1115 x 2140
Operating Weight (with
starters),lb.(kg)
Shipping Weight, (with
starters),lb.(kg)

COMPRESSORS, SCREW, SEMI-HERMETIC

Nominal Tons, (kW) 85 (300) 100 (350)) 100 (350) 100 (350) 105 (365 105 (365

FLOODED EVAPORATOR

Quantity, (Number of Water
Passes)
Shell Diameter – Tube Length 18 - 12 18 - 12 22 - 12
in. - ft. (mm - mm) (457 - 3658) (457 - 3658) (559 - 3658)
Water Volume, gallons (L) 42 (160) 36.9 (140) 62.2 (236)
Max. Water Pressure, psi (kPa) 150 (1035) 150 (1035) 150 (1035)
Max. Refrigerant Pressure, psi
(kPa)
Water Connections (Victaulic), in
(mm)

CONDENSER

Quantity, (Number of Water
Passes)
Shell Diameter -- Tube Length 18 - 12 18 - 12 20 - 12
in. - ft. (mm - mm) (457 - 3658) (457 - 3658) (508 - 3658)
Water Volume, gallons (L) 51.6 (196) 45.2 (171) 61.3 (232)
Max. Water Pressure, psi (kPa) 150 (1035) 150 (1035) 150 (1035)
Max. Refrigerant Pressure, psi
(kPa)
Water Connections (Victaulic), in
(mm)

187.9 (658) 197.3 (691) 218.0 (763)

9970 (4522) 9970 (4522) 12060 (5469)

9567 (4339) 9567 (4339) 11300 (5125)

1 (1,2,3) 1 (1,2,3) 1 (1,2,3)

250 (1725) 250 (1725) 400 (2760)

6 (152) 6 (152) 8 (204)

1 (2,3) 1 (2,3) 1 (2,3)

300 (2070) 300 (2070) 475 (3278)

6 (152) 6 (152) 6 (152)

IOMM WHS WHS 155A - 220A 17

Dimensional Data

Figure 13, WHS 155 - 200

All dimensions are shown in

inches and (mm).

Overall Length

1 & 3 2 & 4 Pass 2 & 4 Pass Height With

Pass Head Conn.

169 1/4 162 3/4 169 1/4 76 7/8 42

(4299) (4134) (4299) (1953) (1067)

Operating 79 3/8 35 1/2 13 7/8 9970

Shipping 79 5/8 34 5/8 14 9567

A Overall

On Same End

X Y Z lb (kg)

(2016) (902) (353) ((4522)

(2023) (880) (356) (4334)

Head Conn.

Both Ends

Center of Gravity

with Starter Weights

(Note 12) Starter

Overall

Width

See notes on next page

18 WHS 155A- 220A IOMM WHS

WHS 155 - 200 Continued

Vessel Code Head Connection U.S. Pipe

Size

Evap. Cond. 1P 2P 3P

E1812 8 6 5 4 7/8

C1812 N.A. 6 5 4 7/8

Notes

1. One half inch (13) FPT evaporator and condenser relief valves must be piped per ANSI/ASHRAE 15. (1 for each evaporator, 2
for each condenser).

2. 168 inches (4267) is required at either end of the tubesheet for tube replacement. 36 inches (914) is recommended on all other
sides and top for service clearance.

3. Final connections must allow for manufacturing tolerance.

4. Standard heads are shown. For dimensions of high pressure construction, water boxes, or flange type connections, contact
your representative.

5. For dimensions of different condenser or evaporator pass see table.

6. Unit is shipped with an operating charge of refrigerant and oil.

7. Six 2 1/2 inch (64) dia. Lifting holes are provided.

8. All water connections are given in standard U.S. Pipe sizes. Standard connections are suitable for welding or victualic couplings.

9. Vibration isolator pads are provided for field installation 0.25 inches (6) thick when loaded.

10. f main power wiring is brought up through the floor, this wiring must be outside the envelope of the unit.

11. Pumpdown capacity is determined in accordance with ANSI/ASHRAE 15 for the maximum tube count.

12. These values are for units with standard wall thickness copper tubing only.

13. The shipping skid adds 4 inches (102) to the overall unit height.

AA BB

(124)

(124)

4 7/8
(124)
4 7/8
(124)

IOMM WHS WHS 155A - 220A 19

Figure 14, WHS 220

All dimensions are shown

in inches and (mm)

Overall Length

1 & 3 2 & 4 Pass 2 & 4 Pass Height With

Pass Head Conn on

169 1/4 163 3/4 169 1/4 84 1/4 47 7/8

(4299) (4159) (4299) (2141) (1114)

Operating 78 3/8 38 1/2 15 1/2 12,060

Shipping 78 5/8 37 7/8 15 5/8 11,300

A Overall

same end

X Y Z lb (kg)

(1991) (978) (394) (5464)

(1997) (962) (397) (5125)

Head Conn.

both ends

Center of Gravity

with Starter Weights

(Note 12) Starter

Overall

Width

See Notes on Next Page.

20 WHS 155A- 220A IOMM WHS

WHS 220 Continued

Vessel Code Head Connection U.S. Pipe

Size

Evap. Cond. 1P 2P 3P

E2212 10 8 6 5 3/4

C2012 N.A. 8 5 5 5/8

Notes:

1. One half inch (13) FPT evaporator and condenser relief valves must be piped per ANSI/ASHRAE 15. (1 for each
evaporator, 2 for each condenser).

2. 144 inches (3658) is required at either end of the tubesheet for tube replacement. 36 inches (914) is recommended on all
other sides and top for service clearance.

3. Final connections must allow for manufacturing tolerance.

4. Standard heads are shown. For dimensions of high pressure construction, water boxes, or flange type connections,
contact your representative.

5. For dimensions of different condenser or evaporator pass see table

6. Unit is shipped with an operating charge of refrigerant and oil.

7. Six 2 1/2 inch (64) dia. Lifting holes are provided.

8. All water connections are given in standard U.S. Pipe sizes. Standard connections are suitable for welding or victualic
couplings.

9. Vibration isolator pads are provided for field installation 0.25 inches (6) thick when loaded.

10. If main power wiring is brought up through the floor, this wiring must be outside the envelope of the unit.

11. Pumpdown capacity is determined in accordance with ANSI/ASHRAE 15 for the maximum tube count.

12. The shipping skid adds 4 inches (102) to the overall unit height.

AA BB

(145)

(143)

6 3/8
(161)

6 3/16

(157)

IOMM WHS WHS 155A - 220A 21

Field Wiring

Unit

Load

Amps

Delta-Delta Start

Size

VoltsHzComp. 1

Comp. 2

Comp. 1

Comp. 2

230

162

162

1042

1042

155A

380609898604

604

4608181

489

489

5756565

377

377

230

162

202

1042

1042

170A

3806098

122

604

604

46081101

489

489

5756581

377

377

230

202

202

1042

1042

180A

38060122

122

604

604

460

101

101

489

489

5758181

377

377

230

202

230

1042

1042

190A

38060122

139

604

604

460

101

115

489

489

5758192

377

377

230

230

230

1042

1042

200A

38060139

139

604

604

460

115

115

489

489

5759292

377

377

230

259

259

1042

1042

220A

38060157

157

604

604

460

130

130

489

489

575

104

104

377

377

WHS unit compressors are single direction rotation compressors. For this reason proper
phasing of electrical power is essential. Electrical phasing must be A, B, C clockwise for
electrical phases 1, 2 and 3 (A=L1 ,B=L2,C=L3). The unit is supplied with single point factory
power connection and includes one MotorSaver phase failure, phase reversal protective device
that will prevent operation of the unit with incorrect power phasing. The MotorSaver is factory
wired and tested. Do not alter the wiring to the MotorSaver.

General Information

Wiring must comply with all applicable codes and ordinances. Warranty is void if wiring is not in
accordance with specifications. Copper wire must be used for all wiring.

The WHS is typically supplied with the main power wiring for single point power connection. A
single large power terminal block is provided. Wiring within the unit is sized according to the National
Electrical Code. A single field-mounted disconnect (supplied by others) is required. An optional
factory mounted transformer for the 115 volt control circuit may have been provided.

Main power must enter the control panel at the location indicated on the unit illustration.

CAUTION

Table 7, Compressor Amp Draw

NOTES:

1. Allowable voltage is within ±10 % of nameplate rating.

2. Compressor RLA values are for wiring sizing only. They do not reflect normal operating current draw at unit rated capacity.

22 WHS 155A- 220A IOMM WHS

Table 8, Customer Wiring Information, WHS 155A - 200A

WHS Wiring to Unit Power Block Wiring to Disconnect Switch

Unit Volts Hz Power Block Optional Disconnect Switch

Size Terminal Size Connector Wire Range (per phase) Size Wire Range (per phase)

Amps (Copper Wire Only) (Copper Wire Only)
208 665 (1) #6-350 MCM & (1) #4-500 MCM 600 (2) 250-350 MCM
230 665 (1) #6-350 MCM & (1) #4-500 MCM 400 (2) 3/0-250 MCM

155A 380 60 335 (1) #6-400 MCM 250 (1) #4-350 MCM

460 335 (1) #6-400 MCM 250 (1) #4-350 MCM
575 335 (1) #6-400 MCM 250 (1) #4-350 MCM
208 665 (1) #6-350 MCM & (1) #4-500 MCM 600 (2) 250-350 MCM
230 665 (1) #6-350 MCM & (1) #4-500 MCM 600 (2) 250-350 MCM

170A 380 60 335 (1) #6-400 MCM 400 (2) 3/0-250 MCM

460 335 (1) #6-400 MCM 250 (1) #4-350 MCM
575 335 (1) #6-400 MCM 250 (1) #4-350 MCM
208 665 (1) #6-350 MCM & (1) #4-500 MCM 600 (2) 250-350 MCM
230 665 (1) #6-350 MCM & (1) #4-500 MCM 600 (2) 250-350 MCM

180A 380 60 335 (1) #6-400 MCM 400 (1) 2/0-500 MCM

460 335 (1) #6-400 MCM 250 (1) #4-350 MCM
575 335 (1) #6-400 MCM 250 (1) #4-350 MCM
208 665 (1) #6-350 MCM & (1) #4-500 MCM 600 (2) 250-350 MCM
230 665 (1) #6-350 MCM & (1) #4-500 MCM 600 (2) 250-350 MCM

190A 380 60 335 (1) #6-400 MCM 400 (1) 2/0-500 MCM

460 335 (1) #6-400 MCM 250 (1) #4-350 MCM
575 335 (1) #6-400 MCM 250 (1) #4-350 MCM
208 665 (1) #6-350 MCM & (1) #4-500 MCM 600 (2) 250-350 MCM
230 665 (1) #6-350 MCM & (1) #4-500 MCM 600 (2) 250-350 MCM

200A 380 60 335 (1) #6-400 MCM 400 (1) 2/0-500 MCM

460 335 (1) #6-400 MCM 400 (1) 2/0-500 MCM
575 335 (1) #6-400 MCM 250 (1) #4-350 MCM

Note:

Allowable voltage is within ±10 percent of nameplate rating.

Table 9, Customer Wiring Information, WHS 220

WHS Wiring to unit Power Block Wiring to Main Circuit Breaker

Unit Volts Hz Power Block Optional Main Circuit Breaker

Size Terminal Size

Amps

Ckt.1 / Ckt.2 Ckt.1 / Ckt.2 Ckt.1 / Ckt.2 Ckt.1 / Ckt.2

208 665 / 665 (1) # 6-350 MCM & (1) # 4-500 MCM & NA NA

230 665 / 665 (1) # 6-350 MCM & (1) # 4-500 MCM & NA NA

220A 60 (1) # 6-350 MCM & (1) # 4-500 MCM

380 665 (1) # 6-350 MCM & (1) # 4-500 MCM 400 (2) 3/0-250 MCM
460 335 (1) # 6-400 MCM 400 (1) 2/0-500 MCM
575 335 (1) # 6-400 MCM 250 (1) #4-350 MCM

Note:

Allowable voltage is within ±10 percent of nameplate rating.

Connector Wire Range (per phase)

(Copper Wire Only)

(1) # 6-350 MCM & (1) # 4-500 MCM

Size Wire Range (per phase)

(Copper Wire Only)

IOMM WHS WHS 155A - 220A 23

Table 10, Electrical Data, WHS 155A - 200A

WHS Minimum Power Supply Field Fuse Size

Unit Volts Hz Circuit Field Wire Recom-

Size Ampacity (MCA) Qty. Wire Gauge mended Maximum

208 403 6 250 450 500
230 365 6 3/0 450 500

155A 380 60 221 3 4/0 250 300

460 183 3 3/0 225 250
575 147 3 1/0 175 200
208 458 6 250 600 600
230 415 6 250 500 600

170A 380 60 251 3 250 300 350

460 208 3 4/0 250 300
575 167 3 2/0 200 225
208 502 6 250 600 700
230 455 6 250 600 600

180A 380 60 275 3 300 350 350

460 228 3 4/0 300 300
575 183 3 3/0 225 250
208 541 6 300 700 700
230 490 6 250 600 700

190A 380 60 296 3 350 350 400

460 245 3 250 300 350
575 196 3 3/0 225 250
208 572 6 350 700 800
230 518 6 300 600 700

200A 380 60 313 3 400 400 450

460 259 3 300 300 350
575 207 3 4/0 250 250

Table 11, Electrical Data, WHS 220A

WHS Minimum Power Supply Field Fuse Size

Unit Volts Hz Circuit Ampacity Field Wire Recom- Maximum

Size (MCA) Qty. (3) Wire Guage mended

Ckt.1 / Ckt.2 Ckt.1 / Ckt.2 Ckt.1 / Ckt.2 Ckt.1 / Ckt.2 Ckt.1 / Ckt.2
208 358 / 358 6 / 6 3/0 / 3/0 450 / 450 600 / 600
230 324 / 324 6 / 6 2/0 / 2/0 400 / 400 500 / 500

220A 380 60 353 6 3 / 0 400 500

460 293 3 350 350 400
575 234 3 250 300 300

NOTES:

1. Allowable voltage range is within ±10% of nameplate rating.

2. Minimum circuit ampacity is equal to 125% of the RLA of the largest motor plus 100% of the RLA of all other loads in the circuit.

3. Recommended power lead wire sizes based on three conductors per conduit at 100% conductor ampacity using 75°C wire and no more
than 3 conductors per conduit.

4. For six conductors per conduit current carrying capacity is reduced by 20%. Consult the National Electrical Code for wire sizing. All
terminal block connections must be made with copper wire (type THW or THHN).

5. Recommended time delay fuse size or circuit breakers (Canadian units only) is equal to 150% of the largest compressor-motor RLA plus
100% of all other loads on the circuit. Maximum time delay fuse size or circuit breakers (Canadian units only) is equal to 225% of the
largest compressor-motor RLA plus 100% of all other loads on the circuit.

6. RLA plus 100% of all other loads on the circuit. Maximum time delay fuse size or circuit breakers (Canadian units only) is equal to 225%
of the largest compressor-motor RLA plus 100% of all other loads on the circuit.

24 WHS 155A- 220A IOMM WHS

Figure 15, Typical Field Wiring

IOMM WHS WHS 155A - 220A 25

Pre-Start-up

1. Open all electrical disconnects and check electrical connections are tight.

2. Verify water piping flow directions are correct and properly connected at the evaporator and

condenser.

3. Using a phase tester, verify electrical phasing is A-B-C clockwise (A=L1, B=L2, C=L3).

4. Verify unit power supply is within 10% of nameplate rating.

5. Verify power supply wiring is the correct size and has a minimum temperature insulation rating of

75°C.

6. Verify all mechanical and electrical inspections have been completed according to local code.

7. Make certain all auxiliary control equipment is operative and an adequate cooling load is

available.

8. Check all compressor valve connections for tightness.

9. Open compressor suction valve until backseated.

10. Open discharge shutoff valve until backseated.

11. Vent air from the evaporator and condenser water system piping.

12. Open all water flow valves and start chilled water pump.

13. Check all piping for leaks.

14. Flush the evaporator and condenser system piping.

Sequence of Operation

The following sequence of operation is typical for McQuay models WHS 155A through WHS 220A
rotary screw water chillers. The sequence may vary depending on the software revision or various
options that maybe installed on the chiller.

Initial Conditions

Before energizing the control box, do the following:

1. Verify the two control circuits are powered through the primary fuses FU1, FU2 and the

secondary fuse FU3.

2. Verify power is developed through the transformer CPT in the starter and is 120 VAC on the

secondary.

3. Make certain the S1 switch is in the off position.

When applying power to the control for the first time do the following:

1. Open left door and the top door to each control box.

2. Apply power and observe the following:

§ Display lights up

§ Unit Status screen appears

§ EXV board lights rapidly sequence closed.

3. Listen for stepper motors closing with a racheting sound.

4. Verify Unit Status Screen on the display indicates Off: Front Panel Sw.

26 WHS 155A- 220A IOMM WHS

Off Conditions

With power on the controller there are several "off" states possible:
Off: Manual: when the setpoint in menu “11 Control Mode” is set to the Mode= Manual Off. To

change, simply set the Mode= Auto: Network (or any other running mode).
Off: Front Panel Sw: when the panel switch is in the “Stop” position. To change move the switch to

“Auto” position.

Off Alarm remove the alarm state then clear the alarm to remove this off state.
Off Compressor 1 or Off Compressor 2 is the on / off switch inside the top right control box door.

Turn to ‘on’ to clear.

Alarm

The alarm light on the front panel illuminates when the particular control receives an active alarm state.
The unit or a particular compressor will be locked out. The other compressor will start if only one is
locked out by a compressor fault.

Initial Start-up

CAUTION

Initial Start-up must be performed by authorized McQuay Service personnel.

1. Set up control as described in Initial Conditions.

2. Turn front panel switch to Auto position (chilled water pump relay will energize).

3. If the field installed flow indicator does not indicated chilled water flow after 30 seconds, then the

alarm output will be energized.

Note: The unit starts the compressor with the least starts and run hours while in auto lead lag
setting.

4. When the Active Setpoint is 3°F lower than the actual leaving water temperature, the chiller

starts.

5. When the chiller starts the following occurs:

§ Crank case heaters de-energize

§ Compressor starts

§ Liquid injection solenoid is energized

§ Motor cooling solenoid is energized

§ Suction injection solenoids are energized

6. Suction injection will turn off when the following conditions have been met:

§ Discharge superheat drops below 3°F

§ Liquid Presence sensor shows liquid

§ Absolute Pressure ratio is greater than 1.2 ( Condenser psia / Evaporator psia)

IOMM WHS WHS 155A - 220A 27

7. The unit status changes:

FROM TO

EvapOn-Recirc **Sec All Systems Off

All Systems Off MCR Started

MCR Started Pre-purge

Pre-purge Open Solenoid

Open Solenoid Running Min Amp Lim

Running Min Amp Lim Running: % Cap 50

8. The following occurs if additional cooling capacity is required:

§ Controllers add capacity by changing the capacity control solenoids outputs 6, 7, and 8.

§ As capacity increases the second compressor is started.

§ After both compressors are running, the unit continues to load by changing the capacity

control solenoids outputs 12, 13, and 14.

Load Recycle

As chilled water requirements lessen, the controls unload the compressors until the chilled water
drops below the lag cutoff point for the delay time required. The control will shut off the lag
compressor and reduced load will cause the leaving water temperature to drop 3°F below the active
setpoint. The compressor de-energizes on Load Recycle and the display will show Waiting For Load.
The chilled water pump will remain on.

Maintenance

General

On initial start-up and periodically during operation, it will be necessary to perform certain routine
service checks. Among these are checking the liquid line sightglasses and taking condensing and
section pressure readings. Through the MicroTech keypad, check to see that the unit has normal
superheat and subcooling readings. A recommended maintenance schedule is located at the end of
this section.

Compressor Maintenance

Since the compressor is semi-hermetic requiring no oil separator, oil heaters and pumps, no yearly
maintenance is normally required. However, vibration is an excellent check for proper mechanical
operation. Compressor vibration is an indicator of the requirement for maintenance and contributes to
a decrease in unit performance and efficiency. It is recommended that the compressor be checked with
a vibration analyzer at or shortly after start-up and again on an annual basis. When performing the
test the load should be maintained as closely as possible to the load of the original test. The initial
vibration analyzer test provides a benchmark of the compressor and when performed routinely can
give a warning of impending problems. The compressor is checked at the factory for maximum
vibration of 0.14 IPS (3.56 mm/s) at 3600 rpm.

The compressor is supplied with a lifetime oil filter under normal operating conditions. However, it is a
good policy to replace this filter anytime the compressor is opened for servicing.

Lubrication

No routine lubrication is required on WHS units.
Compressor oil must be Planetelf ACD68AW. This is a polar synthetic oil with anti-wear additives

and is highly hygroscopic. Care must be taken to minimize exposure of the oil to air and moisture
when charging oil into the system.

28 WHS 155A- 220A IOMM WHS

Electrical Terminals

WARNING

Electric shock hazard. Turn off all power before continuing with following service.

Disconnect power from unit and check electrical terminals for tightness annually.

Condensers

The condensers are water-cooled and subject to tube fouling depending on the level of water
treatment to the cooling water. Under normal conditions the condenser tubes should be examined
annually to check for fouling.

If the service technician has reason to believe that the refrigerant circuit contains noncondensables,
purging of the condenser may be required strictly following regulations governing refrigerant
discharge to the atmosphere. Purge with the unit off, after shutdown of 15 minutes or longer, to allow
air to collect at the top of the coil. Restart and run the unit for a brief period. If necessary, shut unit
off and repeat the procedure. Follow all refrigerant discharge regulations and sound service practices
when purging non-condensables or removing refrigerant from the unit.

Refrigerant Sightglass

The refrigerant sightglass should be observed periodically. (A weekly observation should be
adequate.) A clear glass of liquid indicates that there is adequate refrigerant charge in the system to
insure proper feed through the expansion valve. Bubbling refrigerant in the sightglass, during stable
run conditions, indicates that the system may be short of refrigerant charge. Refrigerant gas flashing
in the sightglass could also indicate an excessive pressure drop in the liquid line, possibly due to a
clogged filter-drier or a restriction elsewhere in the liquid line. If subcooling is low add charge to clear
the sightglass. If subcooling is normal (10°-15°F) and flashing is visible in the sightglass check the
pressure drop across the filter-drier.

An element inside the sightglass indicates the moisture condition corresponding to a given element
color. If the sightglass does not indicate a dry condition after about 12 hours of operation, the circuit
should be pumped down and the filter-drier changed.

Lead-Lag

A feature on all McQuay WHS water-cooled chillers is a system for alternating the sequence in which
the compressors start to balance the number of starts and run hours. Lead-Lag of the refrigerant
circuits is accomplished automatically through the MicroTech Controller. When in the auto mode the
circuit with the fewest number of starts will be started first. If all circuits are operating and a stage
down in the number of operating compressors is required, the circuit with the most operating hours
will cycle off first. The operator may override the MicroTech controller, and manually select circuit
#1or #2 as the lead circuit.

IOMM WHS WHS 155A - 220A 29

Preventative Maintenance Schedule

PREVENTATIVE MAINTENANCE SCHEDULE

OPERATION WEEKLY MONTHLY

(Note 1)
General
Complete unit log and review (Note 3) X
Visually inspect unit for loose or damaged components X
Inspect thermal insulation for integrity X
Clean and paint as required X

Electrical
Check terminals for looseness X
Clean control panel interior X
Visually inspect components for signs of overheating X
Verify compressor heater operation X
Megger compressor motor every five years (Note 5)

Refrigeration
Leak test X
Check sight glasses for clear flow X
Check filter-drier pressure drop (see manual for spec) X
Perform compressor vibration test X

ANNUAL

(Note 2)

Condenser
Check and clean tubes (Note 4) X

Notes:

1. Monthly operations include all weekly operations.

2. Annual (or spring start-up) operations includes all weekly and monthly operations.

3. Log readings may be taken daily for a higher level of unit observation.

4. Tube cleaning may be required more frequently in areas with poor water quality or marginal water treatment.

5. Do not Megger motor while in a vacuum.

30 WHS 155A- 220A IOMM WHS

13600 Industrial Park Boulevard, P.O. Box 1551, Minneapolis, MN 55440 USA [phone]