McQuay WMC-145D Installation Manual
Installation and Maintenance Manual
IMM WMC-2
Group: Chiller
Part Number: 331374601
Effective: November 2007
Supersedes: August 2007
Water-Cooled Centrifugal Chiller
With Oil-Free Magnetic Bearing Compressors
Model WMC-145S to 290D (50/60 Hertz)
R-134a
Table of Contents
Introduction...........................................3
................................................ 3 Nomenclature
Installation.............................................4
................................ 4 Receiving and Handling
Location and Mounting ........................5
.................................................. 5 Water Piping
.............................................. 8 Field Insulation
Physical Data and Weights
............................ 8
DimensionsError! Bookmark not defined.
Dimensions.............................................9
Pressure Drop Curves.........................16
Relief Valves.........................................17
Electrical Data.....................................19
............................................... 19 Power Wiring
WMC 145S, Single Compressor
System Pumps
.............................................. 25
.............................. 22 Single Point Connection
................. 20
........ 20 WMC 145D, 150D Dual Compressors
..... 21 WMC250D and 290D Dual Compressor
....................... 24 Use with On-Site Generators
................................... 25 VFD Line Harmonics
.................................. 28 Multiple Chiller Setup
............................. 30 Prestart System Checklist
Operation .............................................31
............................. 31 Operator Responsibilities
Compressor Operation
................................. 31
......................................... 31 Operating Limits:
................................... 32 MicroTech II Control
Building Automation Systems ............33
Capacity Control System
............................................. 36 Surge and Stall
............................. 35
................... 36 Normal Unit Startup/Shutdown
.................... 37 Annual Unit Startup/Shutdown
Maintenance ........................................38
......................... 38 Pressure/Temperature Chart
Routine Maintenance
................................... 38
.......................................... 39 Repair of System
Maintenance Schedule ........................42
Service Programs ................................43
Operator Schools.................................43
Limited Warranty ...............................43
*
*Unit Controllers are LonMark certified with an optional LonWorks communication module.
Manufactured in an ISO Certified Facility
Document: Catalog WMC-4
Issue Date: August 2007
Replaces: Catalog WMC-2
©2007 McQuay International. Illustrations and data cover the McQuay International product at the time of publication and we reserve the
right to make changes in design and construction at anytime without notice. ™® The following are trademarks or registered trademarks of
their respective companies: BACnet from ASHRAE;
used by L
from AST ElectroFin Inc.; Modbus from Schneider Electric; FanTrol, MicroTech II, Open Choices, and SpeedTrol from McQuay
International.
ONMARK International under a license granted by Echelon Corporation; Compliant Scroll from Copeland Corporation; ElectroFin
LONMARK, LonTalk, LONWORKS, and the LONMARK logo are managed, granted and
2 Centrifugal Chillers IMM WMC-2
Introduction
General Description
The McQuay Model WMC Centrifugal Water Chillers are complete, self-contained, automatically controlled,
fluid-chilling units featuring oil-free, magnetic bearing compressors. Each unit is completely assembled and
factory tested before shipment.
The WMC chillers are equipped with two compressors operating in parallel with a single evaporator and single
condenser. The model WMC 145S has a single compressor.
The chillers use refrigerant R-134a that operates at a positive pressure over the entire operation range, so no
purge system is required.
The controls are pre-wired, adjusted and tested. Only normal field connections such as water piping, relief valve
piping, electric power and control interlocks are required, thereby simplifying installation and increasing
reliability. Necessary equipment protection and operating controls are included.
All McQuay centrifugal chillers are factory-tested prior to shipment and must be commissioned by a factorytrained McQuay service technician. Failure to follow this startup procedure can affect the equipment warranty.
The standard limited warranty on this equipment covers parts that 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 condenser water 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 on optimum entering water
temperature and cooling tower fan control, consult the “Condenser Water” section on page
7.
Nomenclature
W M C 290 D
Centrifugal Compressor
Dangers indicate a hazardous situation which will result in death or serious injury if not avoided.
Warnings indicate potentially hazardous situations, which can result in property damage, severe
Water-cooled
Magnetic Bearings
D=Dual Compressors
S=Single Compressor
Nominal Tons
HAZARD IDENTIFICATION INFORMATION
! DANGER
! WARNING
personal injury, or death if not avoided.
! CAUTION
Cautions indicate potentially hazardous situations, which can result in personal injury or
equipment damage if not avoided.
IMM WMC-2 Centrifugal Chillers 3
Installation
t
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.
On units with factory-installed insulation, the insulation is removed from the vessel lifting hole (also used for
transportation tie-downs) locations and are shipped loose. They should be glued in place after the unit is finally
placed. Neoprene vibration pads are also shipped loose. Check that these items have been delivered with the
unit. They are usually placed in a control panel.
If so equipped, leave the shipping skid in place until the unit is in its final position. This will aid in handling the
equipment.
Extreme care must be used when rigging the unit to prevent damage to the control panels and refrigerant piping.
See the certified dimension drawings included in the job submittal for the center of gravity of the unit. If the
drawings are not available, consult the local McQuay sales office for assistance.
The unit can be lifted by fastening the rigging hooks to the four corners of the unit where the rigging eyes are
located (see
panels, piping and electrical panels.
Figure 1, WMC-D, Major Component Locations
Figure 1). Spreader bars must be used between the rigging lines to prevent damage to the control
Combined Discharge
Check and Shutoff Valve
Control Panel
Compressor #1
Suction Shutoff Valve
Touch Screen, OITS
Evaporator Relief Valve
Outle
Evaporator
Outlet
Inlet
Condenser
Condenser
Relief Valves
Compressor #2 Operator Interface
Rigging Holes
Each Corner
Circuit #2
Power Panel
Circuit #1
Power Panel
Electronic Expansion Valve
Optional Single-Point
Power Block or
Disconnect Switch
4 Centrifugal Chillers IMM WMC-2
Location and Mounting
Clearance
The unit must be mounted on a level concrete or steel base and must be located to provide service clearance at
one end of the unit for possible removal of evaporator and/or condenser tubes. Evaporator and condenser tubes
are rolled into the tube sheets to permit replacement if necessary. The length of the vessel should be allowed at
one end. Doors or removable wall sections can be utilized. Clearance at all sides, including the top, is 3 feet (1
meter). The U.S. National Electric Code (NEC) or local codes can require more clearance in and around
electrical components (4-feet in front of electrical panels) and must be checked for compliance.
Vibration Pads
The shipped-loose neoprene vibration pads (shipped in the power panels) should be located under the corners of
the unit (unless the job specifications state otherwise). They are installed to be flush with the sides and outside
edge of the feet.
Insulation Corners
Insulation corners that cover the rigging holes on the upper corners of the vessel end plates are shipped loose (in
the power panels) and should be installed with adhesive after the init is set in place.
Mounting
Make sure that the floor or structural support is adequate to support the full operating weight of the complete
unit.
It is not 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.
Note: Units are shipped with refrigerant valves closed to isolate the refrigerant in the unit condenser.
Valves must remain closed until start-up by the McQuay technician.
Nameplates
There are several identification nameplates on the chiller:
• The unit nameplate is located on the Unit Control Panel. It has a Model No. XXXX and Serial No. XXXX.
Both are unique to the unit and will identify it. These numbers should be used to identify the unit for service,
parts, or warranty questions. This plate also has the unit refrigerant charge.
• Vessel nameplates are located on the evaporator and condenser. Along with other information, they have a
National Board Number (NB) and a serial number, either of which identify the vessel (but not the entire
unit).
Water Piping
Vessel Drains at Start-up
The unit is tilted and drained of water in the factory and shipped with open drain valves in each head of the
evaporator and condenser. Be sure to close the valves prior to filling the vessel with fluid.
Evaporator and Condenser Water Piping
All evaporators and condensers come standard 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 size and type required.
! CAUTION
Freeze Notice: Neither the evaporator nor the condenser is self-draining; both must be blown out
to help avoid damage from freezing temperatures.
IMM WMC-2 Centrifugal Chillers 5
The piping should 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, use new head gaskets and relocate the control sensors.
In cases where the water pump noise can be objectionable, vibration 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 they can be required where noise and vibration are critical.
Important Notes on Welding
If welding is to be performed on the mechanical or flange connections:
1. Remove the solid-state temperature sensor, thermostat bulbs and optional nozzle mounted flow switches (if so
equipped) from the wells to prevent damage to those components.
2. Properly ground the unit or severe damage to the MicroTech II® unit controller can occur.
Note: ASME certification will be revoked if welding is performed on a vessel shell or tube sheet.
Water pressure gauge connection taps and gauges must be provided in the field piping at the inlet and outlet
connections of both vessels for measuring the water pressure drop. The pressure drops and flow rates for the
various evaporators and condensers are job specific and the original job documentation can be consulted for this
information. Refer to the nameplate on the vessel shell for identification.
Connections
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 connection to maximize subcooling. The
evaporator outlet is on the side of the unit with the two power panels, regardless of which end the connections are
on. See
Figure 1.
! CAUTION
When common piping is used for both building heating and cooling modes, care must be taken to
provide that water flowing through the evaporator cannot exceed 110°F. Water this hot can cause the
relief valve to discharge refrigerant or damage controls.
Piping must be supported to eliminate weight and strain on the fittings and connections. Chilled water piping
must be adequately insulated. A cleanable 20-mesh water strainer must be installed in both water inlet lines.
Sufficient shutoff valves must be installed to permit draining the water from the evaporator or condenser without
draining the complete system.
Flow Switch
Figure 2, Unit-Mounted Flow Switch
Note: Chiller units must have flow switches for the evaporator and
condenser. McQuay furnishes factory-installed and wired, thermaltype flow switches as standard equipment on WMC chillers. Fieldinstalled and wired Delta-P switches can be used instead.
They prevent the unit from starting without sufficient water flow
through the vessels. They also serve to shut down the unit in the
event that water flow is interrupted to guard against evaporator
freeze-up or excessive discharge pressure.
Additionally, for a higher margin of protection, normally open
auxiliary contacts in the pump starters can be wired in series with
the flow switches as shown in the Field Wiring Diagram on page
23.
6 Centrifugal Chillers IMM WMC-2
Cooling Towers
The condenser water flow rate must be checked to be sure that it conforms to the system design. A tower bypass
valve, controlled by the unit controller, is required to control the minimum condenser entering temperature.
Unless the system and chiller unit are specifically designed for them, condenser bypass or variable condenser
flow is not recommended, since low condenser flow rates can cause unstable operation and excessive tube
fouling.
Condenser Water Temperature
When the ambient wet bulb temperature is lower than design, the entering condenser water temperature can be
allowed to fall, improving chiller performance.
McQuay chillers will start with entering condenser water temperature as low as 55°F (12.8°C) providing the
chilled water temperature is below the condenser water temperature.
Depending on local climatic conditions, using the lowest possible entering condenser water temperature can be
more costly in total system power consumed than the expected savings in chiller power would suggest due to the
excessive fan power required.
To obtain lower than 55°F (12.8°C) entering condenser water temperature with a tower selected to produce 85°F
(29.4°C) water temperature at design ambient air temperatures, cooling tower fans must continue to operate at
100% capacity at low wet bulb temperatures. As chillers are selected for lower kW per ton, the cooling tower fan
motor power becomes a higher percentage of the peak load chiller power. The offsets of compressor power and
fan power must be examined. On the other hand, the low condenser water temperatures can be easy and
economical to achieve in mild climates with low wet bulb temperatures.
Even with tower fan control, some form of water flow control such as tower bypass must be used and controlled
by the chiller MicroTech II controller.
Figure 3 and Figure 4 illustrate two temperature-actuated tower bypass arrangements. The “Cold Weather”
scheme, Figure 4, provides better startup under cold ambient air temperature conditions. The check valve may be
required to prevent air at the pump inlet.
Figure 3, Tower Bypass, Mild Weather Operation
! CAUTION
Tower water treatment is essential for continued efficient and reliable unit operation. If not
available in-house, competent water treatment specialists should be contracted.
Figure 4, Tower Bypass, Cold Weather Operation
IMM WMC-2 Centrifugal Chillers 7
Field Insulation
If the optional factory-installation of thermal insulation is not ordered, insulation should be field installed to
reduce heat loss and prevent condensation from forming. Insulation should cover the evaporator barrel, tube
sheet, and water heads, plus the suction line to the compressor flange and the compressor end bell opposite the
suction connection.
The optional factory-installed insulation of cold surfaces includes the evaporator and non-connection water
head, suction piping, compressor inlet, and motor housing.
Insulation is UL recognized (File # E55475). It is 3/4" thick ABS/PVC flexible foam with a skin. The K
factor is 0.28 at 75°F. Sheet insulation is fitted and cemented in place forming a vapor barrier, then painted
with a resilient epoxy finish that resists cracking.
The insulation complies to or has been tested in accordance with the following:
ASTM-C-177 ASTM-C-534 Type 2 UL 94-5V
ASTM-D-1056-91-2C1 ASTM E 84 MEA 186-86-M Vol. N
CAN/ULC S102-M88
Physical Data and Weights
Evaporator
Refrigerant-side design pressure is 200 psi (1380 kPa). Water-side is 150 psi (1034 kPa).
Approximate total square footage of insulation surface required for individual packaged chillers is tabulated by
evaporator code and can be found below. The suction elbow and compressor also require insulation.
Table 1, Evaporator Physical Data
2
)
Number of
Relief
Valves
WMC Model
145S, 145D E2209
150D E2212
250D E2609
290D E2612
Notes:
1. Refrigerant charge is for the entire unit and is approximate since the actual charge will depend on other variables. Actual charge will
be shown on the unit nameplate.
2. Water capacity is based on standard tube configuration and standard dished heads.
Evaporator Tube
Code Length
9 ft. 590 (268) 38 (145) 66 (6.1) 1
12 ft. 790 (358) 45 (170) 90 (8.3) 1
9 ft. 850 (386) 61 (231) 76 (7.1) 1
12 ft. 1150 (522) 72 (273) 102 (9.4) 1
Maximum Unit
Refrigerant Charge
lb. (kg)
Evaporator
Water
Volume, gal (L)
Insulation
Area
sq. ft. (m
Condenser
With positive pressure systems, the pressure variance with temperature is always predictable, and the vessel
design and pressure relief protection are based upon pure refrigerant characteristics. R-134a requires ASME
vessel design, inspection and testing and uses spring-loaded pressure relief valves. When an over-pressure
condition occurs, spring-loaded relief valves purge only that quantity of refrigerant required to reduce the
pressure to the valve’s set pressure and then close.
Refrigerant-side design pressure is 200 psi (1380 kPa). Water-side design is 150 psi (1034 kPa).
Table 2, Condenser Physical Data
WMC Model
145S, 145D C2009
150D C2012
250D C2209
290D C2212
Notes:
1. Condenser pumpdown capacity based on 90% full at 90°F.
2. Water capacity based on standard configuration and standard heads and can be less with lower tube counts.
3. See Relief Valves section for additional information.
4. See page 8 for unit operating, shipping and corner weights.
Condenser
Code
Tube
Length
9 ft. 724 (328) 47 (147) 2
12 ft. 971 (440) 62 (236) 2
9 ft. 883 (401) 61 (231) 2
12 ft. 1174 (533) 72 (273) 2
Maximum
Pumpdown
Capacity lb. (kg)
Water
Volume
gal. (L)
Number of
Relief Valves
8 Centrifugal Chillers IMM WMC-2
Dimensions
WMC 145SFigure 5, (NOTE: See page 14 for notes.)
IMM WMC-2 Centrifugal Chillers 9
Figure 6, WMC 145D (See page 14 for notes.)
10 Centrifugal Chillers IMM WMC-2
Figure 7, WMC 150D, 2-Pass Evaporator, 2-Pass Condenser ( See page 14 for notes.)
IMM WMC-2 Centrifugal Chillers 11
WM C 250DFigure 8, , 2-Pass Evaporator, 2-Pass Condenser
(NOTE: See page 14
for notes.)
12 Centrifugal Chillers IMM WMC-2
Figure 9, WMC 290D, 2-Pass Evaporator, 2- Pass Condenser (See page 14 for notes.)
IMM WMC-2 Centrifugal Chillers 13
Drawing Notes
NOTES:
1. All dimensions are in Inches and [Millimeters] unless noted otherwise.
2. Final connections must allow for .500 inch +/- [12.7mm] manufacturing tolerances.
3. 1.00-inch FPT [25.4 mm] evaporator and condenser relief valves must be piped per ANSI / ASHRAE 15.
Number of relief valves is 1 per evaporator and 2 per condenser.
4. .375 inch [9 mm] suction nozzle relief valve must be piped per ANSI / ASHRAE 15.
5. Clearances:
Ends, 108 inches (2743 mm) on WMC 145, WMC 150 with 9 foot tubes, and WMC 250
144 inches (3658 mm) on WMC 150 with 12 foot tubes and WMC 290
plus 36 inches (910) is required at either end of the tube sheet for tube maintenance. If
clearance is at the connection end, do not bloct tube access with piping, pumps, etc.
Sides 36 inches (914 mm) is recommended on all other sides and top for service clearance.
Electric Panels Most codes require 48 inches (1219 mm) clearance in front of the control boxes and electrical
panels.
6. 3.25-inch [83mm] diameter lifting holes are provided. See installation manual for lifting instructions.
7. All water connections are given in standard U.S. pipe sizes. Standard connections are suitable for welding or
victaulic couplings.
8. Unit shown has standard left-hand water connections. Right-hand connections are available for either vessel.
For right hand evaporator the inlet and outlet nozzles are reversed. ANSI-flanged connections are available upon
request. When using ANSI-flanged connections add .500 inch [13 mm] to each flanged end.
9. Dimensions shown are for units (evaporator / condenser) with standard design pressures. The refrigerant side
design pressure is 200 PSI {1380 kPa} and the waterside design pressure is 150 PSI {1034 kPa}. Consult the
factory for unit dimensions with higher design pressures.
10. The unit vibration isolator pads are provided for field installation. When fully loaded - .250 inches [6 mm]
thick.
11. These values are for units with standard wall thickness copper tubing only.
12. The shipping skid, when used, adds 4.00 inches [105 mm] to the overall unit height.
13. If main power wiring is brought up through the floor, this wiring must be outside the envelope of the unit.
14. Typical wiring connections to the compressor control box are multi-power wiring into the top of each box.
The unit control box has a lower section that contains a disconnect switch when the optional single-point
connection is selected and is the landing point for the power connection. Otherwise it is empty.
15. The unit is shipped with an operating charge of refrigerant.
16. Optional marine water box connections are available upon request.
Table 3, Overall Dimensions, 2-Pass Vessels
In. (mm)
Length
Width
Height
WMC 145S, WMC 145D WMC 150 WMC 250 WMC 290
Same End Opp. End Same End Opp. End Same End Opp. End Same End Opp. End
135 (3429) 141 (3581) 171 (4343) 177 (4496)
39 (991) 39 (991) 35 (889) 35 (889) 44 (1117) 44 (1117) 44 (1117) 44 (1117)
80 (2032) 80 (2032) 80 (2032) 80 (2032) 83 (2108) 83 (2108) 83 (2108) 83 (2108)
135 (3429)
141 (3581) 171 (4343) 177 (4496)
14 Centrifugal Chillers IMM WMC-2
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