Magnitude™ Magnetic Bearing Centrifugal Chillers Model WMC-145SBS to 400DBS Installation Manual HFC-134a

Installation Manual
IM 1029-2
Group: Chiller
Part Number: 331374611
Effective: September 2010
Supercedes: July 2010
Magnitude™ Magnetic Bearing Centrifugal Chillers
Model WMC-145SBS to 400DBS
HFC-134a
Table of Contents
Electrical Data..................................... 24
Receiving and Handling .................................4
Power Wiring ............................................... 24
VFD Line Harmonics................................... 38
Fuses ............................................................ 40
System Pumps .............................................. 40
Multiple Chiller Setup.................................. 40
Location and Mounting ........................5
Prestart System Checklist .................. 43
Water Piping...................................................5
Field Insulation...............................................8
Operation............................................. 44
Introduction...........................................3
Nomenclature .................................................3
Installation .............................................4
Operator Responsibilities............................. 44
Compressor Operation ................................. 44
Operating Limits: ......................................... 44
MicroTech II Control ................................... 45
Use with On-Site Generators ....................... 46
Building Automation Systems...................... 47
Physical Data and Weights ...................9
Chiller Dimensions.............................. 11
Harmonic Filter Dimensions ..............18
Relief Valves.........................................22
*
*Unit Controllers are LonMark certified with an optional LonWorks communication module.
Manufactured in an ISO Certified Facility
Document:
Issue Date:
Revision Date
Replaces:
IM 1029-2
June 2010
Sept. 2010
May 2010
©2010 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; LONMARK, LonTalk, LONW ORKS, and the LONMARK logo are managed,
granted and used by LONMARK International under a license granted by Echelon Corporation; Modbus from Schneider Electric;
MicroTech II, and Open Choices from McQuay International.
2
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
IM 1029-2
Introduction
General Description
The McQuay Magnitude™ Frictionless Centrifugal 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.
They are designed for indoor, non-freezing installation only.
Magnitude 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.
Nomenclature
W M C 290 D BS
Vintage/Single Circuit.
Water-cooled
Magnetic Bearings
D=Dual Compressors
S=Single Compressor
Centrifugal Compressor
Nominal Tons
HAZARD IDENTIFICATION INFORMATION
!
DANGER
Dangers indicate a hazardous situation which will result in death or serious injury if not
avoided.
!
WARNING
Warnings indicate potentially hazardous situations, which can result in property damage,
severe 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.
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Magnitude™ Frictionless Centrifugal Chillers – Model WMC
3
Installation
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 secured in place after the unit is
finally placed. Neoprene vibration pads are also shipped loose 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 Figure 1). A spreader bar must be used between the rigging lines to prevent damage to the control
panels, piping and electrical panels. The spreader-bar length should be equal to, or no more then 1-foot shorter
than the distance between the lifting holes located at opposite ends of the chiller. The unit will require a single
spreader-bar of this length capable of supporting 1.5 times the shipping weight of the unit. Separately, all cables
and hooks by themselves must also be capable of supporting 1.5 times the shipping weight of the unit.
Figure 1, WMC, Major Component Locations
Combined Discharge
Check and Shutoff Valve
Compressor #1
Suction Shutoff Valve
Compressor #2
Power Panel
Control Panel
Evap. Relief Valve
(Behind Panel)
Rigging Holes
Each Corner
Evaporator
Condenser
Relief Valves
Behind Panel
Outlet
Inlet
Condenser
Operator Interface
Touch Screen, OITS
4
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
IM 1029-2
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.
They are designed for indoor, non-freezing installation suitable for NEMA 1 enclosures.
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 factory service 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. Victaulic connections are AWWA C-606 on 14-inch and larger sizes.
Field supply transitions if Victaulic brand AGS® (Advanced Groove System) type grooves are used on the field
piping.
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Magnitude™ Frictionless Centrifugal Chillers – Model WMC
5
!
CAUTION
Freeze Notice: Neither the evaporator nor the condenser is self-draining;
both must be blown out to help avoid damage from freezing temperatures.
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 right side of the head, regardless of which end the connections are on. Refer to
dimension drawings beginning on page 11.
!
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. Sufficient shutoff valves must be installed to permit draining the water from the
evaporator or condenser without draining the complete system and to allow vessel isolation.
Filtering and Treatment
Owners and operators must be aware that if the unit is operating with a cooling tower, cleaning and flushing the
cooling tower is required. Make sure tower blow-down or bleed-off is operating. Atmospheric air contains many
contaminants, which increases the need for water treatment. The use of untreated water will result in corrosion,
erosion, slime buildup, scaling, or algae formation. Water treatment service must be used. McQuay International
is not responsible for damage or faulty operation from untreated or improperly treated water.
Special care must be taken when utilizing open system water that is usually not treated (such as lakes, rivers, and
ponds). Special tube and water head material may be required to reduce damage from corrosion.
A cleanable 20-mesh water strainer must be installed in both vessels’ water inlet lines.
6
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
IM 1029-2
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 Magnitude chillers.
Field-installed 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.
Figure 2, Unit-Mounted Flow Switch
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 37.
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.
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.
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 since most of the piping
is indoors and not subjected to cold ambient air. The check valve may be required to prevent air at the pump
inlet.
IM 1029-2
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
7
Figure 4, Tower Bypass, Cold
Weather Operation
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.
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.
•
The suction line from the top of the evaporator to the compressor inlet flange.
•
The compressor support brackets welded to the evaporator.
•
The liquid line from the expansion valve outlet to the evaporator inlet.
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
Approximate total square footage of insulation surface required for individual packaged chillers is tabulated by
evaporator code and can be found below.
Table 1, Insulation Quantity
8
WMC Model
Evaporator
Code
145S,
145D
150D
250D
290D
400D
E2209
E2209
E2212
E2609
E2612
E3012
Insulation
Area
sq. ft. (m2)
66 (6.1)
66 (6.1)
90 (8.3)
76 (7.1)
102 (9.4)
114 (11)
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
IM 1029-2
Physical Data and Weights
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. See Relief Valves section for additional information.
Evaporator
Refrigerant-side design pressure is 200 psi (1380 kPa). Water-side is 150 psi (1034 kPa).
Table 2, Evaporator Physical Data
WMC Model
Evaporator
Code
Tube
Length
145S,
145D
150D
250D
290D
400D
E2209
E2209
E2212
E2609
E2612
E3012
9 ft.
9 ft.
12 ft.
9 ft.
12 ft.
12 ft.
Unit Refrigerant
Charge
lb. (kg)
500 (227)
600 (272)
800 (363)
600 (272)
1100 (500)
1240 (562)
Evaporator
Water
Volume, gal (L)
38 (145)
38 (145)
45 (170)
61 (231)
72 (273)
88 (336)
Number of
Relief
Valves
1
1
1
1
1
1
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.
Condenser
Refrigerant-side design pressure is 200 psi (1380 kPa). Water-side design is 150 psi (1034 kPa).
Table 3, Condenser Physical Data
WMC Model
Condenser
Code
Tube
Length
Maximum
Pumpdown
Capacity lb. (kg)
724 (328)
971 (440)
883 (401)
1174 (533)
1676 (760)
Water
Volume
gal. (L)
47 (147)
62 (236)
61 (231)
72 (273)
111 (419)
Number of
Relief Valves
9 ft.
2
145S, 145D
C2009
12 ft.
2
150D
C2012
9 ft.
2
250D
C2209
12 ft.
2
290D
C2212
12 ft.
2
400D
C2612
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.
IM 1029-2
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
9
Mounting/Lifting/Total Weights
Drawings are for reference only and are not indicative of all unit configurations.
10
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
IM 1029-2
Chiller Dimensions
Figure 5, WMC
IM 1029-2
145S, 2 Pass (See page 17 for notes.)
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
11
Figure 6, WMC
12
145D, 2 Pass (See page 17 for notes.)
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
IM 1029-2
Figure 7, WMC
IM 1029-2
150D, 2-Pass (See page 17 for notes.)
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
13
Figure 8, WMC
14
250D, 2-Pass (See page 17 for notes.)
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
IM 1029-2
Figure 9, WMC
IM 1029-2
290D, 2-Pass (See page 17 for notes.)
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
15
Figure 10, WMC
16
400D, 2-Pass (See page 17 for notes.)
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
IM 1029-2
Drawing Notes
NOTES:
1. All dimensions are in inches and [millimeters] unless noted otherwise.
2. Final connections must allow for +/- 0.5 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. 0.375 inch [9 mm] suction nozzle relief valve must be piped per ANSI / ASHRAE 15.
5. Minimum clearances are shown below.
Table 4 Minimum Clearance Requirements
WMC Model
145S, 145D
250D
150D, 290D
400D
One End
in. (mm)
Opposite End
in. (mm)
Sides & Top
in. (mm)
Electric Panels
in. (mm)
112 (2845)
36 (914)
36 (914)
48 (1219)
147 (3734)
36 (914)
36 (914)
48 (1219)
NOTES:
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
a. The “One End” clearance is for tube removal and can be provided by a door or window.
b. Local codes may require greater than 48 inches for electric panel clearance.
3.25-inch [83mm] diameter lifting holes are provided. See installation manual for lifting instructions.
All water connections are given in standard U.S. pipe sizes. Standard connections are suitable for
welding or victaulic couplings.
The water connection shown is for the default configuration; your unit may be configured differently.
Orientation (left/right) is determined while facing the control panel. Consult the Item Summary sheet for
exact configuration. Unit shown has standard right-hand water connections. Left-hand connections are
available for either vessel. For left hand evaporator the inlet and outlet nozzles are reversed. ANSIflanged connections are available upon request. When using ANSI-flanged connections add .500 inch
[13 mm] to each flanged end.
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.
The unit vibration isolator pads are provided for field installation. When fully loaded - .250 inches [6
mm] thick.
These values are for units with standard wall thickness copper tubing only.
The shipping skid, when used, adds 6.00 inches [152 mm] to the overall unit height.
If main power wiring is brought up through the floor, this wiring must be outside the envelope of the
unit.
All power wiring is brought to the top of the power panel (Front End Box). Control wiring is brought to
the (Unit Control Box).
The unit is shipped with an operating charge of refrigerant.
Optional marine water box connections are available upon request.
IM 1029-2
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
17
Harmonic Filter Dimensions
18
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
IM 1029-2
Pressure Drop Curves
NOTE: The Evaporator and Condenser Model Codes are shown on page 9. The -B and -C designations shown
on the curves refer to vessel tube count, which is determined by the computer selection program.
Figure 11, Single Pass Evaporators
WMC Evap - Water Side Pressure Drop
(1 pass)
30
E2212-B
E2212-C
E2212-D
25
E2209-B
E2209-C
EPD - ft
20
E2209-D
E2612-B
E2609-B
15
E3012-B
E3012-C
10
5
0
0
500
1000
1500
2000
2500
3000
3500
4000
EGPM - gpm
Figure 12, Single Pass Condensers
WMC Cond - Water Side Pressure Drop
(1 pass)
25.0
C2012-B
C2012-C
20.0
C2009-B
C2009-C
C2212-B
C2212-C
CPD - ft
15.0
C2209-B
C2209-C
C2612-B
10.0
C2612-C
5.0
0.0
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
CGPM - gpm
IM 1029-2
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
19
Figure 13, 2-Pass Evaporators
WMC Evap - Water Side Pressure Drop
(2 pass)
60
E2212-B
E2212-C
E2212-D
50
E2209-B
E2209-C
E2209-D
40
EPD - ft
E2612-B
E2609-B
E3012-B
30
E3012-C
20
10
0
0
500
1000
1500
2000
EGPM - gpm
Figure 14, 2-Pass Condensers
WMC Cond - Water Side Pressure Drop
(2 pass)
35.0
C2012-B
C2012-C
30.0
C2009-B
C2009-C
25.0
C2212-B
CPD - ft
C2212-C
C2209-B
20.0
C2209-C
C2612-B
15.0
C2612-C
10.0
5.0
0.0
0
500
1000
1500
2000
2500
CGPM - gpm
20
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
IM 1029-2
Figure 15, 3-Pass Evaporators
WMC Evap - Water Side Pressure Drop
(3 pass)
90
E2212-C
E2212-D
80
E2209-C
E2209-D
70
E2612-B
E2609-B
EPD - ft
60
E3012-C
50
40
30
20
10
0
0
200
400
600
800
1000
1200
EGPM - gpm
Figure 16, 3-Pass Condensers
WMC Cond - Water Side Pressure Drop
(3 pass)
60.0
C2012-C
C2009-C
50.0
C2212-C
C2209-C
CPD - ft
40.0
C2612-C
30.0
20.0
10.0
0.0
0
200
400
600
800
1000
1200
1400
CGPM - gpm
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Magnitude™ Frictionless Centrifugal Chillers – Model WMC
21
Relief Valves
As a safety precaution and to meet code requirements, each
chiller is equipped with pressure relief valves located on the
condenser and evaporator for the purpose of relieving excessive
refrigerant pressure (caused by equipment malfunction, fire,
etc.) to the atmosphere. Most codes require that relief valves be
vented to the outside of a building and this is a desirable
practice for all installations. Relief piping connections to the
relief valves must have flexible connectors.
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 must be run in
accordance with local code requirements; where local
codes do not apply, the latest issue of ANSI/ASHRAE
Standard 15 code recommendations must be followed.
•
Condensers have two relief valves as a set with a three-way
valve separating the two valves. One valve remains active at
all times and the second valve acts as a standby.
•
Evaporators have a single valve. Each valve has a 1.0-inch
female NPT connection.
•
Each suction line on dual compressor units has a single 200 psig relief valve rated at 5 lb/min air with a
3/8-inch flare connection.
Vessel valve capacity is 990.4 SCFM
Figure 17, Condenser 3-Way Relief Valve
Refrigerant Vent Piping
Vessel relief valve connection size is 1-inch FPT and are in the quantity shown in Table 2 and Table 3 on page
9. Twin relief valves mounted on a transfer valve are used on the condenser so that one relief valve can be shut
off and removed for testing, leaving the other in operation. Only one of the two is in operation at any time.
Vent piping is sized for only one valve of the set (but connected to both) 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 on the current ANSI/ASHRAE
Standard 15 that recommends 90% full at 90°F (32°C).
22
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
IM 1029-2
Sizing Vent Piping (ASHRAE Method)
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 R-134a vessels is calculated using a complicated equation that
accounts for equivalent length of pipe, valve capacity, Moody friction factor, pipe ID, outlet pressure and back
pressure. The formula and tables are contained in ASHRAE Standard 15-2001.
The McQuay Magnitude centrifugal units have a relief valve setting of 200 psi.
Using the ASHRAE formula and basing calculations on the 225 psi design yields a conservative pipe size, which
is summarized in Table 5. The table gives the pipe size required per relief valve. When valves are piped
together, the common piping must follow the rules set out in the following paragraph on common piping.
Table 5. Relief Valve Piping Sizes
Equivalent length (ft)
Pipe Size inch (NPT)
Moody Factor
2.2
1 1/4
0.0209
18.5
1 1/2
0.0202
105.8
2
0.0190
296.7
2 1/2
0.0182
973.6
3
0.0173
4117.4
4
0.0163
NOTE: A 1-inch pipe is too small to handle these valves. A pipe increaser must always be installed at the valve outlet.
Common Piping
According to ASHRAE Standard 15, the pipe size cannot be less than the relief valve outlet size. The discharge
from more than one relief valve can be run into a common header, the area of which cannot 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:
0.5
DCommon =  D12 + D22 .... Dn2 
The above information is a guide only. Consult local codes and/or latest version of ASHRAE Standard 15 for
sizing data.
IM 1029-2
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
23
Electrical Data
Wiring, fuse and wire size must be in accordance with the National Electric Code (NEC).
Important: The voltage to these units must be within ±10% of nameplate voltage, and the voltage unbalance
between phases must not exceed 2%. Since a 2% voltage unbalance will cause a current unbalance of 6 to 10
times the voltage unbalance per NEMA MG-1, 1998 Standard, it is most important that the unbalance between
phases be kept at a minimum.
Power Wiring
The standard power wiring connection to Magnitude chillers is single point to a common disconnect switch
which is then factory-wired to individual circuit breakers for each circuit.
The electrical panel contains the circuit breaker/ disconnect (standard on both multi-point connection and singlepoint connection), a line reactor. The circuit breakers provide compressor overload protection.
Proper phase sequence to the unit is not required as far as the unit operation is concerned. Correct motor
rotation is established by the chiller control system regardless of the connected phase sequence.
!
DANGER
Qualified and licensed electricians must perform wiring. An electrical shock hazard exists that
can cause severe injury or death.
The field power wiring required varies depending on unit model, and if optional EMI filters and/or harmonic
filters (including tuning reactors and referred to in this manual as combo harmonic filters) have been ordered.
Factory-mounted and wired line reactors are standard, but discarded when the optional combo harmonic filters
are included. Table 6 gives the various wiring cases as a function of unit model and filters used.
NOTE: Harmonic filter dimensions, weights, connection size and location are in the Dimension Section
beginning on page 18.
Table 6, Field Wiring Cases
Standard With
Standard Line Reactors
With Optional
EMI Filters
WMC 145S
Case 1
Case 7
Case 8
Case 9
WMC 145D, 150D
Case 1
Case 2
Case 5
Case 6
WMC 250D, 290D, 400D
Case 1
Case 2
Case 3
Case 4
WMC Model
With Optional Combo With Optional Combo
Harmonic Filters
Harmonic Filters and EMI
Case 1, Field Power Wiring
Case 1 applies to standard units that also include standard line reactors. The standard connection is to two
disconnect switches on multi-point connection or to a single disconnect switch (or optional power block) on
optional single-point connection.
Figure 18, Case 1 Wiring
Multi-Point
Disconnect
Switch, Circuit #1
24
Single-Point
Disconnect
Switch, Circuit #2
Disconnect Switch or
Optional Power Block
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
IM 1029-2
Case 2, WMC 145D – 400D Field Power Wiring
Case 2 adds optional factory-mounted and wired EMI filters. The actual field wiring is the same as Case 1.
Figure 19, Case 2 Field Power Wiring
Case 3, WMC 250D, 290D, 400D Field power Wiring
Case 3 adds the combo harmonic filters. The standard line reactors are shipped in the unit and are removed and
discarded in the field. The field wiring to the harmonic filter would be the same size as the incoming lines.
Figure 20 shows the optional multi-point connection to two disconnect switches. The standard would be a
single-point connection to a single disconnect switch.
IM 1029-2
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
25
Figure 20, Case 3 Field Power Wiring
Case 4, WMC 250D, 290D, 400D Field Power Wiring
Case 4 adds both the EMI filters and the combo harmonic filters.
The EMI is factory mounted and the line side of the EMI is factory wired, the load side is field wired to the
remotely mounted harmonic filter.
The standard line reactors are shipped in the unit and are removed and discarded in the field. The field wiring
size to and from the harmonic filter should be the same as the incoming lines.
Figure 21 shows the optional multi-point connection to two disconnect switches. The standard would be a
single-point connection to a single disconnect switch. The balance of the wiring remains the same.
26
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
IM 1029-2
Figure 21, Case 4 Field Power Wiring
IM 1029-2
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
27
Case 5, WMC 145D – 150D Field Power Wiring
Case 5 adds remote-mounted combo harmonic filters. In these model WMCs the fuses are located in the
compressor. Field wiring is run from the circuit breaker load side to the power block in the remote filter.
The standard line reactors are shipped in the unit and are removed and discarded in the field. A shipped loose
power block is field mounted in their former location and one side is wired to the remote filter. The wires that
originally ran from the line reactor up to the compressor are now connected to the other side of the power block.
NOTE: the fuses and compressor shown in the “Chiller” block are located in the compressors on these models,
not in the power panel. The wire routing is shown in Figure 22.
Figure 22, WMC 145D, 150D Case 5 Field Power Wiring
Case 6, WMC 145D – 150D Field Power Wiring
Refer to Case 5. Case 6 merely adds factory-mounted EMIs to the load side of the circuit breaker. The EMI load
side is wired out to the harmonic filter. In other words, the EMI is interposed between the breaker and the filter
Figure 23, WMC 145D, 150D Case 6 Field Power Wiring
28
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
IM 1029-2
Case 7, WMC 145S Field Power Wiring
Case 7 adds an optional factory-mounted and wired EMI filter. The actual field wiring is to the circuit breaker as
in Case 1, Single-Point.
Case 8, WMC 145S Field Power Wiring
Case 5 adds a remote-mounted combo harmonic filter. Field wiring runs from the load side of the circuit breaker
to the power block in the remote harmonic filter.
The standard line reactors are shipped in the unit and are removed and discarded in the field. A shipped loose
power block is field mounted in their former location and one side is wired to the remote filter. The wires that
originally ran from the line reactor up to the compressor are now connected to the other side of the field supplied
power block.
Figure 24, Case 8 WMC 145S Field Power Wiring
Case 9 WMC 145S Field Power Wiring
Case 9 adds a factory-mounted EMI to the remote-mounted harmonic filter. The field wiring remains the same as
Case 8 except that the wiring out to the filter emanates from the EMI rather than the circuit breaker as in Case 8.
IM 1029-2
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
29
Table 7, Electrical Acronyms and Notes
ACRONYMS:
DS
LRA
N/A
MCA
MOP
PB
Disconnect switch
Locked rotor amps
Not available
Minimum circuit ampacity
Maximum overcurrent protection
Power block
RLA
Rated load amps
NOTES:
1
Disconnect switch will also be a circuit breaker for short circuit protection.
2
On single-point connection a circuit breaker for short-circuit protection is installed downstream of
the power block or disconnect switch.
3
4
RLA and LRA data is for each compressor
Wire size per NEC 2008, table 310.16, 75° C, copper
5
MOP size per NEC 2008, section 440.22(a) for air conditioning and refrigeration equip.
General Note: The RLA for use in the following tables is obtained by the selection of a specific unit by McQuay.
When shipped, a unit will bear the specific RLA, stamped on the nameplate, for the selected operating conditions.
!
CAUTION
The RLA stamped on the unit may be lower than the minimum shown in the following tables, in
which case the minimum table value must be used for wire sizing.
WMC 145S, 3/60/460 Only
Table 8, WMC 145SBS, 3/60/460
SINGLE POINT CONNECTION, STANDARD
COMPRESSOR
RLA
[Amp]
LRA
[Amp]
QTY
MCA
[Amp]
MOP
[Amp]
79 to 80
81 to 88
89 to 92
93 to 99
110
110
110
110
1
1
1
1
99 to 100
101 to 110
111 to 115
116 to 123
175
175
200
200
CHILLER
DISC.
POWER
SWT.
BLOCK
[Amp]
[Amp]
150
150
150
150
WIRE
QTY
WIRE
GAUGE
3
3
3
3
3 GA
2 GA
2 GA
1 GA
100
110
1
125
225
150
101 to 104
105 to 111
132
132
1
1
126 to 130
131 to 138
225
225
200
200
112 to 120
132
1
140 to 150
250
121 to 133
154
1
151 to 166
250
134 to 140
154
1
167 to 175
300
225
3
2/0
141 to 150
165
1
176 to 187
300
225
3
3/0
30
3
1 GA
3
3
1 GA
1/0
200
3
1/0
225
3
2/0
N/A
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
IM 1029-2
WMC 145D & 150D, 3/60/460 & 3/60/575
Table 9, WMC 145DBS & WMC 150DBS, 3/60/460
SINGLE POINT CONNECTION, STANDARD
COMPRESSOR
CHILLER
DISC.
POWER
SWT.
BLOCK
[Amp]
[Amp]
250
760
250
760
250
760
RLA
[Amp]
LRA
[Amp]
QTY
MCA
[Amp]
MOP
[Amp]
WIRE
QTY
WIRE
GAUGE
52 to 53
54 to 57
58 to 61
71
71
71
2
2
2
117 to 120
122 to 129
131 to 138
150
175
175
3
3
3
1 GA
1 GA
1/0
62 to 64
71
2
140 to 144
200
250
65 to 69
70 to 76
77
88
88
88
2
2
2
147 to 156
158 to 171
173
200
225
250
250
250
250
760
3
1/0
760
760
760
3
3
3
2/0
2/0
2/0
78 to 80
88
2
176 to 180
250
250
760
3
3/0
81 to 88
89 to 92
110
110
2
2
182 to 198
200 to 207
250
250
250
250
760
760
3
3
3/0
4/0
93 to 100
110
2
209 to 225
300
250
760
3
4/0
101 to 102
103 to 107
108 to 113
132
132
132
2
2
2
227 to 230
232 to 241
243 to 254
300
300
350
400
400
400
760
760
760
3
3
3
4/0
250MCM
250MCM
114 to 120
132
2
257 to 270
350
400
760
3
300MCM
WIRE
QTY
WIRE
GAUGE
3
3
6 GA
4 GA
3/60/460 Multi-point data is on the following page.
Table 10, WMC 145DBS & WMC 150DBS, 3/60/460
MULTI POINT CONNECTION, OPTIONAL
COMPRESSOR
CHILLER
DISC.
POWER
SWT.
BLOCK
[Amp]
[Amp]
100
N/A
100
N/A
RLA
[Amp]
LRA
[Amp]
QTY
MCA
[Amp]
MOP
[Amp]
52
53 to 55
71
71
2
2
65
66 to 69 A
110
110
56 to 64
71
2
70 to 80 A
125
100
N/A
3
4 GA
65 to 68
69 to 77
88
88
2
2
82 to 85 A
86 to 97 A
150
150
125
125
N/A
N/A
3
3
4 GA
3 GA
78 to 80
88
2
98 to 100
175
125
N/A
3
3 GA
81 to 88
89 to 92
93 to 99
110
110
110
2
2
2
101 to 110
111 to 115
116 to 124
175
200
200
150
150
150
N/A
N/A
N/A
3
3
3
2 GA
2 GA
1 GA
100
110
2
125
225
150
N/A
3
1 GA
101 to 104
105 to 111
132
132
2
2
126 to 130
131 to 139
225
225
200
200
N/A
N/A
3
3
1 GA
1/0
112 to 120
132
2
140 to 150
250
200
N/A
3
1/0
3/60/575 volt data.is on the following page
IM 1029-2
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
31
Table 11, WMC 145DBS & WMC 150DBS, 3/60/575
SINGLE POINT CONNECTION, STANDARD
COMPRESSOR
CHILLER
DISC.
POWER
SWT.
BLOCK
[Amp]
[Amp]
250
760
250
760
250
760
250
760
RLA
[Amp]
LRA
[Amp]
QTY
MCA
[Amp]
MOP
[Amp]
WIRE
QTY
WIRE
GAUGE
51
52 to 53
54 to 57
58 to 61
71
71
71
71
2
2
2
2
115
117 to 120
122 to 128
131 to 138
150
150
175
175
3
3
3
3
2 GA
1 GA
1 GA
1/0
62 to 64
71
2
140 to 144
200
250
65 to 69
70 to 76
77
88
88
88
2
2
2
147 to 155
158 to 171
173
200
225
250
250
250
250
760
3
1/0
760
760
760
3
3
3
2/0
2/0
2/0
78 to 80
88
2
176 to 180
250
250
760
3
3/0
81 to 88
89 to 92
110
110
2
2
182 to 198
200 to 207
250
250
250
250
760
760
3
3
3/0
4/0
93 to 100
110
2
209 to 225
300
250
760
3
4/0
WIRE
QTY
WIRE
GAUGE
3
3
6 GA
4 GA
MULTI POINT CONNECTION, OPTIONAL
COMPRESSOR
32
CHILLER
DISC.
POWER
SWT.
BLOCK
[Amp]
[Amp]
100
N/A
100
N/A
RLA
[Amp]
LRA
[Amp]
QTY
MCA
[Amp]
MOP
[Amp]
51 to 52
53 to 55
71
71
2
2
64 to 65 A
66 to 69
110
110
56 to 64
71
2
70 to 80 A
125
100
N/A
3
4 GA
65 to 68
69 to 77
88
88
2
2
82 to 85 A
86 to 97 A
150
150
125
125
N/A
N/A
3
3
4 GA
3 GA
78 to 80
88
2
98 to 100
175
125
N/A
3
3 GA
81 to 88
89 to 92
93 to 99
110
110
110
2
2
2
101 to 110
111 to 115
116 to 124
175
200
200
150
150
150
N/A
N/A
N/A
3
3
3
2 GA
2 GA
1 GA
100
110
2
125
225
150
N/A
3
1 GA
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
IM 1029-2
WMC 250D & 290D, 3/60/460 Only
Table 12, WMC 250DBS & WMC 290DBS, 3/60/460
SINGLE POINT CONNECTION, STANDARD
COMPRESSOR
RLA
[Amp]
LRA
[Amp]
QTY
MCA [Amp]
MOP
[Amp]
79 to 88
89 to 92
110
110
2
2
178 to 198
201 to 208
250
250
CHILLER
DISC.
POWER
SWT.
BLOCK
[Amp]
[Amp]
250
760
250
760
WIRE
QTY
WIRE
GAUGE
3
3
3/0
4/0
93 to 100
110
2
210 to 226
300
250
760
3
4/0
101 to 107
108 to 113
132
132
2
2
228 to 241
244 to 255
300
350
400
400
760
760
3
3
250 MCM
250 MCM
114 to 120
132
2
257 to 271
350
400
760
3
300 MCM
121 to 123
124 to 126
127 to 137
138
154
154
154
154
2
2
2
2
273 to 277
280 to 284
286 to 309
311
350
400
400
400
400
400
400
400
760
760
760
760
3
3
3
3
300 MCM
300 MCM
350 MCM
400 MCM
139 to 140
154
2
313 to 316
450
400
760
3
400 MCM
141 to 149
165
2
318 to 335
450
400
760
3
400 MCM
150
165
2
338 Amps
450
400
760
3
500 MCM
WIRE
QTY
WIRE
GAUGE
3
3
3
3
3 GA
2 GA
2 GA
1 GA
MULTI POINT CONNECTION, OPTIONAL
COMPRESSOR
CHILLER
DISC.
POWER
SWT.
BLOCK
[Amp]
[Amp]
150
N/A
150
N/A
150
N/A
150
N/A
RLA
[Amp]
LRA
[Amp]
QTY
MCA [Amp]
MOP
[Amp]
79 to 80
81 to 88
89 to 92
93 to 99
110
110
110
110
2
2
2
2
99 to 100
101 to 110
111 to 115
116 to 123
175
175
200
200
100
110
2
125
225
150
N/A
3
1 GA
101 to 104
105 to 111
132
132
2
2
126 to 130
131 to 138
225
225
200
200
N/A
N/A
3
3
1 GA
1/0
112 to 120
132
2
140 to 150
250
200
N/A
3
1/0
121 to 133
154
2
151 to 166
250
225
N/A
3
2/0
134 to 140
154
2
167 to 175
300
225
N/A
3
2/0
141 to 150
165
2
176 to 187
300
225
N/A
3
3/0
IM 1029-2
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
33
WMC 400D 3/60/460 ONLY
Table 13, WMC 400DBS, 3/60/460
SINGLE POINT CONNECTION, STANARD
COMPRESSOR
RLA
[Amp]
LRA
[Amp]
QTY
MCA
[Amp]
MOP
[Amp]
126
127 to 137
138
139 to 148
149 to 153
176
176
176
176
176
2
2
2
2
2
284
286 to 309
311
313 to 334
336 to 345
400
400
400
450
450
154 to 160
176
2
347 to 361
500
CHILLER
DISC.
POWER
SWT.
BLOCK
[Amp]
[Amp]
400
760
400
760
400
760
400
760
400
760
400
760
WIRE
QTY
WIRE
GAUGE
3
3
3
3
3
300 MCM
350 MCM
400 MCM
400 MCM
500 MCM
3
500 MCM
WIRE
QTY
WIRE
GAUGE
3
3
3
2/0
2/0
3/0
3
3/0
MULTI POINT CONNECTION, OPTIONAL
COMPRESSOR
34
RLA
[Amp]
LRA
[Amp]
QTY
MCA
[Amp]
MOP
[Amp]
126 to 133
134 to 140
141 to 155
176
176
176
2
2
2
157 to 166
167 to 175
176 to 193
250
300
300
156 to 160
176
2
195 to 200
350
CHILLER
DISC.
POWER
SWT.
BLOCK
[Amp]
[Amp]
250
N/A
250
N/A
250
N/A
250
N/A
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
IM 1029-2
Figure 25, Power Panel (Front End Box)
Power Cable Entrance
Access Plate on Top
Transformers
T2, T3, T4
Current
Transformer
Power
Connection
Circuit Breaker
w/Lockout,
Comp #1
Ground
Fault Relay
Disconnect Switch w/
Thru-the-Door Handle
Circuit Breaker
w/Lockout, Comp #2
Transformer
T1
Power System
Filter EMI
Comp #2
Power System
Filter EMI
Comp #1
Control Power
Interrupt Relay
(4) Control
Power Fuses
Drive Reactor
Comp #1
IM 1029-2
Drive Reactor
Comp #2
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
35
Figure 26, Control Panel
EXV Board
Field Wiring Knockouts
Terminal Board
TB UTB1 for Field
Wiring Connections
On/Off
Switches
UNIT
COMP #1
COMP #2
Controller
OITS PC
Universal
Communication
Module
Comp #1 I/O
36
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
Comp #2 I/O
IM 1029-2
Figure 27, Field Control Wiring Diagram
NOTE: Complete notes are on the following page.
MICROTECH CONTROL
BOX TERMINALS
(115V)
(24V)
UTB1
PE
GND
54
* REMOTE
ON/OFF
(NOTE 5)
85
POWER
* NOTE 7
NEUTRAL
* NOTE 10
O
MODE SWITCH
55
74
C4
*
70
80
H
* COOLING
TOWER
FOURTH
STAGE
STARTER
86
* NOTE 8
H
A
O
86
A
EP2
86
C
NOTE 11
* NOTE 10
* COOLING
TOWER
THIRD
STAGE
STARTER
O
C3
* NOTE 8
73
A
* CHILLED
WATER
PUMP
STARTERS
EWI-2
79
H
H
O
EWI-1
76
H
O
C2
C
NOTE 11
77
* NOTE 10
* COOLING
TOWER
SECOND
STAGE
STARTER
A
EP1
78
75
A
(NOTE 6)
SWITCH
DELTA P
FLOW OR
EVAP.
CF1
(NOTE 6)
SWITCH
DELTA P
FLOW OR
COND.
* NOTE 10
H
* COOLING
TOWER
FIRST
STAGE
STARTER
C1
EF2
A
H
O
CWI-2
81
82(NO)
* NOTE 4
POWER
C
NOTE 11
CF2
COMMON
A
CP2
EF1
O
* NOTE 9
A
*ALARM RELAY
(NOTE 4)
* CONDENSER
WATER
PUMP
STARTERS
83(NC)
84
52
* NOTE 9
H
*COOLING TOWER BYPASS VALUE
71
O
0-10 VDC
71
CP1
A
C
0-10 VDC
* COOLING TOWER VFD
53
NOTE 11
CWI-1
IM 1029-2
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
37
Field Wiring Diagram Notes
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
Compressor terminal boxes are factory-mounted and wired. All line-side wiring must be in accordance with the NEC and be made
with copper wire and copper lugs only. Power wiring between the terminal box and compressor terminals is factory installed.
Minimum wire size for 115 VAC is 12 ga. for a maximum length of 50 feet. If greater than 50 feet refer to McQuay for
recommended wire size minimum. Wire size for 24 VAC is 18 ga. All wiring to be installed as NEC Class 1 wiring system. All
24 VAC wiring must be run in separate conduit from 115 VAC wiring. Wiring must be wired in accordance with NEC and
connection to be made with copper wire and copper lugs only.
Voltage unbalance not to exceed 2% with a resultant current unbalance of 6 to 10 times the voltage unbalance per NEMA MG-1,
1998 Standard. Supply voltage must be +/- 10% of compressor nameplate voltage.
A customer furnished 24 or 120 vac power for alarm relay coil may be connected between UTB1 terminals 84 power and 81
neutral of the control panel. For normally open contacts wire between 82 & 81. For normally closed wire between 83 & 81. The
alarm is operator programmable. Maximum rating of the alarm relay coil is 25VA.
Remote on/off control of unit can be accomplished by installing a set of dry contacts between terminals 70 and 54.
If field supplied flow switches are used in addition to the factory-mounted flow switches, they must be wired as shown. Pressure
differential switches must be installed across the vessel and not the pump. They must be suitable for 24 vac and low current
application.
Customer supplied 115 VAC 20 amp power for optional evaporator and condenser water pump control power and tower fans is
supplied to unit control terminals (UTB1) 85 power / 86 neutral, PE equipment ground.
Optional customer supplied 115 VAC, 25-VA maximum coil rated, chilled water pump relay (ep1 & 2) may be wired as shown.
This option will cycle the chilled water pump in response to chiller demand.
The condenser water pump must cycle with the unit. A customer supplied 115 VAC 25 VA maximum coil rated, condenser water
pump relay (CP1 & 2) is to be wired as shown. Units with free-cooling must have condenser water above 60°F before starting.
Optional customer supplied 115 VAC 25 VA maximum coil rated cooling tower fan relays (C1 - C2 standard, C3-C4 optional)
may be wired as shown. This option will cycle the cooling tower fans in order to maintain unit head pressure.
Auxiliary 24 VAC rated contacts in both the chilled water and condenser water pump starters can be wired as shown.
4-20mA external signal for chilled water reset are wired to terminals 71 and 51 on the unit controller; load limit is wired to
terminals 71 and 58 on the unit controller.
Optional Control Inputs. The following 4-20 ma optional inputs are connected as shown:
• Demand Limit; Terminals 58 and 71 common
• Chilled Water Reset; Terminals 51 and 71 common
• Evaporator Water Flow; Terminals 59 and 71 common
• Condenser Water Flow; Terminals 60 and 71 common
14. Optional Control Power Source. 115 volt control power can be supplied from a separate circuit and fused at 20 amps inductive
load. Connection is to terminals 85 and 86 common.
15. 4-20 mA external signal for chilled water reset are wired to terminals 71 and 51 on the unit controller; load limit is wired to
terminals 71 and 58 on the unit controller.
Control Wiring
The control circuit on the McQuay centrifugal packaged chiller is designed for 115-volts. Control power is
supplied from a factory-wired transformer located in the electrical box.
VFD Line Harmonics
Despite their many benefits, care must be taken when applying VFDs due to the effect of line harmonics on the
building electric system. VFDs cause distortion of the AC line because they are nonlinear loads, that is, they
don't draw sinusoidal current from the line. They draw their current from only the peaks of the AC line, thereby
flattening the top of the voltage waveform. Some other nonlinear loads are electronic ballasts and
uninterruptible power supplies.
Line harmonics and their associated distortion can be critical to ac-drives for three reasons:
1. Current harmonics can cause additional heating to transformers, conductors, and switchgear.
2. Voltage harmonics upset the smooth voltage sinusoidal waveform.
3. High-frequency components of voltage distortion can interfere with signals transmitted on the AC
line for some control systems.
The harmonics of concern are the 5th, 7th, 11th, and 13th. Even harmonics, harmonics divisible by three, and high
magnitude harmonics are usually not a problem.
38
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
IM 1029-2
Current Harmonics
An increase in reactive impedance in front of the VFD helps reduce the harmonic currents. Reactive impedance
can be added in the following ways:
1.
2.
3.
4.
Mount the drive far from the source transformer.
Add line reactors. They are standard equipment on Magnitude chillers.
Use an isolation transformer.
Use a harmonic filter.
Voltage Harmonics
Voltage distortion is caused by the flow of harmonic currents through a source impedance. A reduction in
source impedance to the point of common coupling (PCC) will result in a reduction in voltage harmonics. This
can be done in the following ways:
1.
2.
3.
4.
Keep the PCC as far from the drives (close to the power source) as possible.
Increase the size (decrease the impedance) of the source transformer.
Increase the capacity (decrease the impedance) of the busway or cables from the source to the PCC.
Make sure that added reactance is "downstream" (closer to the VFD than the source) from the PCC.
Line Reactors
Five-percent line reactors are standard equipment on Magnitude chillers and located in each compressors power
panel. They are employed to improve the power factor by reducing the effects of harmonics.
Harmonic Filter
The harmonic filter is an option for field mounting and wiring outside of the power panel. It works in
conjunction with the line reactor to further minimize harmonic distortion. IEEE 519-1991 Standard defines
acceptable limits.
See the Magnitude certified drawings for harmonic filter dimensions and wiring information.
EMI (Electro Magnetic Interference) and RFI (Radio Frequency Interference) Filter
This filter is a factory-installed option. The terms EMI and RFI are often used interchangeably. EMI is actually
any frequency of electrical noise, whereas RFI is a specific subset of electrical noise on the EMI spectrum.
There are two types of EMI. Conducted EMI is unwanted high frequencies that ride on the AC wave form.
EMI
Radiated EMI is similar to an unwanted radio broadcast being emitted from the power lines. There are many
pieces of equipment that can generate EMI, variable frequency drives included. In the case of variable frequency
drives, the electrical noise produced is primarily contained in the switching edges of the pulse width modulation
(PWM) controller.
As the technology of drives evolves, switching frequencies increase. These increases also increase the effective
edge frequencies produced, thereby increasing the amount of electrical noise.
The power line noise emissions associated with variable frequency and variable speed drives can cause
disturbances in nearby equipment. Typical disturbances include:
•
•
•
•
•
•
Dimmer and ballast instability
Lighting disturbances such as flashing
Poor radio reception
Poor television reception
Instability of control systems
Flow meter totalizing
IM 1029-2
•
•
•
•
•
Flow metering fluctuation
Computer system failures including loss of data
Thermostat control problems
Radar disruption
Sonar disruption
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
39
RFI
Three-phase filters are supplied as an option for factory mounting in the compressor power panels. They use a
combination of high frequency inductors and capacitors to reduce noise in the critical 150 kHz to 30 MHz
frequency range. The inductors act as open circuits and the capacitors act as short circuits at high frequencies
while allowing the lower power line frequencies to pass untouched. The filters assist with cost effective
compliance to Electro Magnetic Compatibility (EMC) directives, in a compact, efficient, light-weight design.
The high common mode and differential mode reduction in the critical 150kHz to 30MHz frequencies assures
that potential interference from AC drives is reduced or eliminated.
The filters are current-rated devices. In order to properly size a filter, it is necessary to know the operating
voltage and the input current rating of the drive. No derating or re-rating is necessary when applying the filter at
voltages that are less than or equal to the maximum voltage listed on the filter.
The IEEE 519-1991 Standard
The Institute of Electrical and Electronics Engineers (IEEE) has developed a standard that defines acceptable
limits of system current and voltage distortion. A simple form is available from McQuay that allows McQuay to
determine compliance with IEEE 519-1991.
Line reactors, isolation transformers, or phase-shifting transformers can be required on some installations.
Fuses
All WMC chillers have power fuses upstream of the compressors. Models WMC 145S, 250D and 290D have
the fuses in the power panel. Models WMC 145D and 150D have them in the top of the compressor, accessible
by removing the compressor top cover.
Fuses are: Manufacturer: Littelfuse, Class: T, Amps: JLLS 175, Volts: 600V.
System Pumps
Operation of the chilled water pump can be to 1) cycle the pump with the compressor, 2) operate continuously,
or 3) 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. A control relay is required if the
voltage-amperage rating is exceeded. See the Field Wiring Diagram on page 37 or in the cover of control panel
for proper connections.
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 alarms must not draw more than 10-volt amperes.
Multiple Chiller Setup
WMC units have their control components factory wired to an internal network (LAN) so that the components
can communicate with each other, within the chiller itself.
On multi-chiller Model WMC applications, up to three Model WMC chillers can be LAN interconnected by
simple field RS485 interconnecting wiring, with the addition of an accessory communication isolation board(s)
485OPDR (McQuay P/N 330276202) between each chiller (one less than the number of chillers connected),
and some MicroTech II control settings. The 485OPDR isolation board can be purchased with the unit or
separately, during or after chiller installation. N-1 boards are required. WMC chillers cannot be LAN
interconnected with WSC, WDC, WCC or WME centrifugal chillers.
Communication Setup
Interconnecting MicroTech II pLAN RS485 wiring should be installed by the installing contractor prior to startup. The McQuay start-up technician will check the connections and make the necessary set point settings.
1. With all manual switches off, turn on control power to each chiller and set each OITS address (see Note 2 on
page Error! Bookmark not defined.).
2. Verify correct nodes on each OITS Service Screen.
3. Connect chillers together (RS485 wiring) as shown in Figure 28. The first chiller in the connection can be
designated as Chiller A. The isolation board is attached to the DIN rail adjacent to the Chiller A unit
controller. The isolation board has a pigtail that is plugged into J10 on the controller. Most chillers will
already have a universal communication module (UCM) that connects the controller to the touchscreen
already plugged onto J10. If this is the case, plug the isolation module pigtail into the empty RJ11 pLAN
port on the UCM. This is equivalent to plugging into the unit controller directly.
Next, interconnecting wiring is needed between Chillers A, B, and C.
Interconnection: Belden M9841 (RS 485 Spec Cable) is wired from the 485OPDR isolation board
(terminals A, B, and C) on Chiller A to the J11 port on the unit controller of Chiller B. At J11, the shield
connects to GND, the blue/white wire to the (+) connection, and the white/blue to the (-) connection.
Note that Chiller B does not have, or need, an isolation board when either two or three units are connected.
4. Verify correct nodes on each OITS Service Screen.
Figure 28, Communication Wiring
Chiller A
485
OPDR
C B A
P
P
J10 J11
UCM
Chiller C
A
P
485
B OPDR
C
P
J10 J11
UCM
Chiller B
C B A
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Magnitude™ Frictionless Centrifugal Chillers – Model WMC
41
MicroTech II Operator Interface Touch Screen (OITS) Settings
Settings for any type of linked multiple compressor operation must be made to the MicroTech II controller.
Settings on a dual compressor unit are made in the factory prior to shipment, and verified in the field before
startup. Settings for multiple chillers are set in the field on the Operator Interface Touch Screen as follows:
Maximum Compressors ON – SETPOINTS - MODES screen, Selection #10 ‘= 2 for a dual, 4 for 2 duals, 3 for
three separate, single compressor chillers, etc. If all compressors in the system are to be available as normal
running compressors, then the value entered in #10 should equal the total number of compressors. If any
compressors are for standby and not operated in normal rotation, they should not be included in the compressor
count in Selection #10. The Max Comp ON setting can be made in only one touchscreen, the system will
observe the highest number set on all chillers-it is a global setting.
Sequence and Staging – SETPOINTS - MODES screen, Selection #12 & #14; #11 & #13. Sequence sets the
sequence in which compressors will start. Setting one or more compressors to “1” evokes the automatic lead/lag
feature and is the normal setting. The compressor with least starts will start first and the compressor with
maximum hours will stop first, and so on. Units with higher numbers will stage on in sequence.
The Modes setpoints will do several different types of operation (Normal, Efficiency, Standby, etc.) as described
in the operating manual.
The same Modes setting must be replicated on each chiller in the system.
Nominal Capacity – SETPOINTS - MOTOR screen, Selection #14. The setting is the compressor design tons.
Compressors on dual units are always of equal capacity.
Operating Sequence
For multiple-chiller, parallel operation, the MicroTech II controllers are tied together by a communications
network and stage and control compressor loading among the chillers. Each compressor, single or dual
compressor chiller, will stage on or off depending on the sequence number programmed into it. For example, if
all are set to “1”, the automatic lead/lag will be in effect.
When chiller #1 is fully loaded, the leaving chilled water temperature will rise slightly. When the Delta-T above
setpoint reaches the Staging Delta-T, the next chiller scheduled to start will receive a start signal and start its
pumps if they are set up to be controlled by the MicroTech II® controller. This procedure is repeated until all
chillers are running. The compressors will load-balance themselves.
If any of the chillers in the group are dual compressor, they will stage and load according to the staging
instructions.
See OM WMC (current edition) for a complete description of the various staging sequences available.
42
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
IM 1029-2
Prestart System Checklist
Yes
No
N/A
Chilled Water
Piping complete........................................................................................
Water system filled, vented ......................................................................
Pumps installed, (rotation checked), strainers cleaned .............................
Controls (3-way, face and bypass dampers, bypass valves, etc.) operable
Strainer installed at evaporator inlet.........................................................
Water system operated and flow balanced to meet unit design requirements
Condenser Water
Cooling tower flushed, filled and vented .................................................
Pumps installed, (rotation checked), strainers cleaned ............................
Strainer installed at condenser inlet..........................................................
Controls (3-way, bypass valves, etc.) operable ........................................
Water system operated and flow-balanced to meet unit requirements .....
Electrical
Power leads connected to the unit power panel(s) ...................................
All interlock wiring complete to control panel and complies with specifications
Pump starters and interlock wired ...........................................................
Cooling tower fans and controls wired ....................................................
Wiring complies with National Electrical Code and local codes .............
Condenser pump starting relay (CWR) installed and wired ....................
Miscellaneous
Relief valve piping complete ...................................................................
Thermometer wells, thermometers, gauges, control wells, controls, etc., installed
Minimum system load of 80% of machine capacity available for testing
and adjusting controls .............................................................................
Control wiring between multiple units, if applicable.........................................................
Note: This checklist must be completed and sent to the local McQuay Factory Service location two weeks prior
to start-up.
IM 1029-2
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
43
Operation
Operator Responsibilities
It is important that the operator become familiar with the equipment and the system before attempting to operate
the chiller.
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.
Now that you have made an investment in modern, efficient McQuay equipment, its care and operation should
be a high priority. For training information on all McQuay HVAC products, please visit us at www.mcquay.com
and click on Training, or phone 540-248-0711 and ask for the Training Department. These sessions are
structured to provide basic classroom instruction and include hands-on operating and troubleshooting exercises.
Compressor Operation
The WMC compressors are two-stage. Suction gas enters the compressor through inlet guide vanes that can be
opened and closed to control refrigerant flow as the cooling load changes. The suction gas enters the first stage
impeller, is compressed, and travels through the vaned radial diffuser to the second stage impeller where
compression is completed. The gas travels to the condenser via the discharge volute, which converts any
remaining velocity pressure to static pressure.
Motor cooling is accomplished by utilizing the refrigerant effect of high-pressure liquid refrigerant from the
condenser expanded to a gas within the compressor. The refrigerant cools VFD heat sinks and the motor.
A five-axis magnetic bearing system supports the motor/compressor shaft, resisting radial and thrust forces. The
bearing control system uses shaft position feedback to continually adjust the bearing to keep the shaft in the
correct position. During coast down or in the event of a power failure, the compressor motor acts as a generator
and in conjunction with on-board capacitors powers the bearing support system. There is also a system to gently
de-levitate the shaft.
Many controls are mounted directly on the compressor where they monitor and control compressor operation.
These compressor controls are interfaced with the conventional MicroTech II controls to provide a complete
chiller control system.
Operating Limits:
Maximum standby ambient temperature, 130°F (55°C)
Minimum operating ambient temperature (standard), 35°F (2°C)
Leaving chilled water range, 36°F to 60°F (2.2°C to 15°C)
Maximum operating evaporator inlet fluid temperature, 66°F (19°C)
Maximum startup evaporator inlet fluid temperature, 90°F (32°C)
Maximum non-operating inlet fluid temperature, 100°F (38°C)
Minimum condenser water entering temperature (with condenser bypass), 55°F (12.8°C)
Maximum entering condenser water temperature, 105°F (40.6°C)
Maximum leaving condenser water temperature, 115°F (46.1°C)
44
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
IM 1029-2
System Water Volume
It is important to have adequate water volume in the system to provide an opportunity for the chiller to sense a
load change, adjust to the change, and stabilize. As the expected load change becomes more rapid, a greater
water volume is needed. The system water volume is the total amount of water in the evaporator, air handling
products and associated piping. If the water volume is too low, operational problems can occur including rapid
compressor cycling, rapid loading and unloading of compressors, erratic refrigerant flow in the chiller, improper
motor cooling, shortened equipment life and other undesirable consequences.
Some of the things the designer should consider when looking at water volume are the minimum cooling load,
the minimum chiller plant capacity during the low load period and the desired cycle time for the compressors.
Assuming that there are no sudden load changes and that the chiller plant has reasonable turndown, a rule of
thumb of “gallons of water volume equal to two to three times the chilled water gpm flow rate” is often used.
For process applications where the cooling load can change rapidly, additional system water volume is needed.
A process example would be a quenching tank. The load would be very stable until the hot material is immersed
in the water tank. Then, the load would increase drastically. For this type of application, system volume may
need to be increased.
Since there are many other factors that can influence performance, systems may successfully operate below
these suggestions. However, as the water volume decreases below these suggestions, the possibility of problems
increases.
Variable Speed Pumping
Variable water flow involves inversely changing the water flow through the evaporator as the load changes.
McQuay chillers are designed for this duty provided that the rate of change in water flow is slow and the
minimum and maximum flow rates for the vessel, as shown in Figure 11 on page 19 are not exceeded.
The recommended maximum change in water flow is 10 percent of the allowable flow change per minute. Flow
is usually not reduced below 50 percent of design flow (provided vessel minimum flow rates are not exceeded).
For example, a 150-ton chiller might have chilled water flow of 360 gpm, reduced to 50 percent, would be 180
gpm. However, the minimum flow rate is 216 gpm, so the flow change would be 360 gpm minus 216 gpm, or
144 gpm. This means that the allowable flow rate change would be 10 percent of 144 or 14.4 gpm per minute.
MicroTech II Control
Figure 29, MicroTech II Control Panel
Magnitude chillers are equipped with the McQuay MicroTech II control system consisting of:
•
Operator interface touchscreen panel with a 15-inch Super VGA color screen.
•
Control Panel containing the MicroTech II unit controller, two MicroTech II compressor controllers with
connections to the compressor-mounted controls, and various switches and field connection terminals.
Operating instructions for the MicroTech II controller are contained in Operating Manual OM 1008.
IM 1029-2
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
45
Use with On-Site Generators
Magnitude chillers (excluding WMC 145S) have their total tonnage divided between two compressors that start
sequentially and they are operated with variable frequency drives. These features make Magnitude chillers
especially appropriate for use in applications where they may be required to run with on-site electrical
generators. This is particularly true when the generators are used for temporary power when the utility power is
lost.
Generator Sizing: Gas and diesel generators are sensitive to the compressor’s locked-rotor characteristics when
the chillers start up. Use the electrical data supplied with the performance output sheet, obtained from the
McQuay sales office, for generator sizing purposes. The chiller data sheet will show the RLA, which is for both
compressors. Refer to Electrical Data to determine the LRA, based on the RLA. It is important to size the
generator to handle the LRA at start up.
Starting/Stopping Procedure: The stopping of the chiller in the event of a power failure should be uneventful.
The chiller will sense a loss of voltage and the compressors will stop, coasting down using power generated
from their dynamic braking to maintain the bearing magnetic field. The stop signal will initiate a three-minute
stop-to-start timer, effectively preventing compressor restart for three minutes. The timer is adjustable from three
to fifteen minutes; the recommended default value is three minutes. This interval allows the generator sufficient
time to get up to speed and stabilize. The chiller will restart automatically when the start-to-start timer expires.
Transfer Back to Grid Power: Proper transfer from stand-by generator power back to grid power is essential to
avoid compressor damage.
!
WARNING
Stop the chiller before transferring supply power from the generator back to the utility power grid. Transferring
power while the chiller is running can cause severe compressor damage.
The necessary procedure for reconnecting power from the generator back to the utility grid is shown below.
These procedures are not peculiar to McQuay units only, but should be observed for any chiller manufacturer.
1. Set the generator to always run five minutes longer than the unit start-to-start timer, which could be set from
15 to 60 minutes. The actual setting can be viewed on the operator interface panel on the Setpoint/Timer
screen.
2. Configure the transfer switch, provided with the generator, to automatically shut down the chiller before
transfer is made. The automatic shut-off function can be accomplished through a BAS interface or with the
“remote on/off” wiring connection shown in the field wiring diagram. A start signal can be given anytime
after the stop signal since the three-minute start-to-start timer will be in effect.
Chiller Control Power: For proper operation on standby power, the chiller control power must remain as
factory-wired from a unit-mounted transformer. Do not supply chiller control power from an external power
source because the chiller may not sense a loss of power and do a normal shutdown sequence.
46
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
IM 1029-2
Building Automation Systems
All MicroTech II controllers with Open Choices™ are capable of BAS communications, providing easy
integration and comprehensive monitoring, control, and two-way data exchange with open standard protocols
such as LonTalk, Modbus or BACnet.
McQuay unit controllers strictly conform to the interoperability guidelines of the LONMARK  Interoperability
Association and BACnet International. They have received LONMARK certification with optional LONWORKS
communication module.
Protocol Options
•
•
•
•
•
BACnet MS/TP
BACnet IP
BACnet Ethernet
LONWORKS (FTT-10A)
Modbus RTU
The BAS communication module can be ordered with a chiller and factory-mounted or can be field-mounted at
any time after the chiller unit is installed.
Table 14, Typical Data Point Availability
Active Setpoint
Actual Capacity
Capacity Limit Output
Capacity Limit Setpoint
Chiller Enable
Chiller Limited
Chiller Local/Remote
Chiller Mode Output
Chiller Mode Setpoint
Chiller On/Off
Chiller Status
Compressor Discharge Temp
Compressor Percent RLA
Compressor Run Hours
Compressor Select
Compressor Starts
Compressor Suction Line
Temp
Typical Data Points1 (W = Write, R = Read)
R
Cond EWT
R
Evap Water Pump Status
R
Cond Flow Switch Status
R
Liquid Line Refrigerant Pressure
R
Cond LWT
R
Liquid Line Refrigerant Temp
W
Cond Pump Run Hours
R
Maximum Send Time
W
Cond Refrigerant Pressure
R
Minimum Send Time
Cond Sat. Refrigerant
R
R
Network Clear Alarm
Temp
R
Cond Water Pump Status
R
Pump Select
R
Cool Setpoint
W
Run Enabled
W
Current Alarm
R
R
Default Values
W
R
Evap EWT
R
R
Evap Flow Switch Status
R
R
Evap LWT for Unit
R
R
Evap LWT for Compressor
R
W
Evap Pump Run Hours
R
R
Evap Refrigerant Pressure
R
Evap Sat. Refrigerant
R
R
Temp
R
R
R
W
W
W
W
R
Note: Data points available are dependent upon options selected.
Connection to Chiller
Connection to the chiller for all BAS protocols will be at the unit controller. An interface card, depending on
the protocol being used, will have been factory installed in the unit controller if so ordered, or it can be field
installed.
Protocols Supported
Table 15, Standard Protocol Data
Protocol
Physical Layer
Data Rate
Controller
Other
BACnet/IP
Ethernet 10 Base-T
BACnet MSTP
RS485
10 Megabits/sec
Color graphics SBC
Reference ED 15057: BACnet PICS
(TBD)
pCO2 Unit Controller
Reference ED 15057: BACnet PICS
LONMARK Chiller Functional
Profile
2
LonTalk
FTT-10A
78kbits/sec
pCO Unit Controller
Modbus RTU
RS-485
(TBD)
pCO2 Unit Controller
NOTE: For additional information on the protocol data available through the BACnet or LonTalk
communications modules, reference McQuay ED 15062, MicroTech II Chiller Unit Controller Protocol
Information.
IM 1029-2
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
47
Modbus - When selected, the ident number and baud can also be changed to suit the application.
LONWORKS – When selected, the ident number and baud rate setpoints are not available. Baud rate is locked at
4800.
BACnet – When selected, the ident number and baud rate setpoints are not available. Baud rate is locked at
19200.
If an interface module was ordered, one of the following BAS interface installation manuals was shipped with
the unit. If necessary, contact your local McQuay sales office for a replacement or obtain from
www.mcquay.com.
Modbus: IM 743
LonWorks: IM 735
BACnet Ethernet or IP: IM 837
BACnet MS/TP: IM 906
48
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
IM 1029-2
IM 1029-2
Magnitude™ Frictionless Centrifugal Chillers – Model WMC
49
This document contains the most current product information as of this printing. For the most up-todate product information, please go to www.mcquay.com.
All McQuay equipment is sold pursuant to McQuay’s Standard Terms and Conditions of Sale and
Limited Product Warranty. Consult your local McQuay Representative for warranty details. Refer
to form 933-430285Y. To find your local representative, go to www.mcquay.com
(800) 432-1342 • www.mcquay.com
IM 1029-2 (9/10)