McQuay | AHS 210CM/B | Specifications | McQuay AHS 210CM/B Specifications

CATALOG
Centrifugal Compressor Water Chillers
THE DISTINCTION SERIES ¥
Model WSC, Single Compressor, Cooling
Model WDC, Dual Compressor, Cooling
Model HSC, Single Compressor Heat Recovery
Model TSC, Single Compressor, Templifier™ Water Heater
R-134a, The Global Refrigerant of Choice
Engineered for flexibility and performance.™
Cat WSCWDC-4
Cutaway view of McQuay Model CE 063 Compressor, Nominal 250 Tons
MicroTech II™ Controller, 12-inch VGA Operator Interface, Home Screen
Table of Contents
Introduction..............................................................3
Customer Benefits Summary....................................5
Heat Recovery Models ...........................................12
Control Features.....................................................15
Building Automation Systems................................21
Unit Design Features..............................................23
Options and Accessories ........................................37
Motor Controllers...................................................39
Refrigerant Recovery Units....................................45
Refrigerant Monitors ............................................. 47
Unit Selection ........................................................ 48
Application Considerations ................................... 50
Chiller Identification.............................................. 63
Physical Data and Weights .................................... 64
Dimensions ............................................................ 66
Supplemental Publications .................................... 79
Specifications......................................................... 80
Cover pictures: Upper unit: Model WSC 087, 500 ton single compressor chiller with factory-mounted starter
Lower unit: Model WDC 126, 2000 ton, dual compressor chiller
ETL applies to
WSC, WDC, only
Document:
Revision:
Replaces:
Cat WSCWDC-4
September 2005
PM WSCWDC-3
Manufactured in an ISO Certified Facility.
Initial Issue October, 1999© McQuay International. "McQuay" is registered trademark of McQuay International.
Data and illustrations cover McQuay International products at the time of publication and we reserve the right to
make changes in design and construction at anytime without notice.
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Catalog WSC/WDC-4
Introduction
There is an excellent reason for naming McQuay’s centrifugal chiller products as “THE
DISTINCTION SERIES”. Our chillers offer customers an unbeatable combination of
performance, reliability, unique construction features, a long-term refrigerant, and
advanced control technology, all adding up to a superior value. After reviewing our
features and benefits, choose the superior value of McQuay centrifugal chillers for your
next project.
Model WDC, Dual Compressor Chiller
•
•
•
•
160 to 2400 tons capacity
Outstanding part load performance
Duplicate components for excellent
reliability
Refer to page 9 for description
Model WSC, Single Compressor Chiller
•
•
•
80 to 1250 tons capacity
Excellent full load performance
Refer to page 5 for description
Model TSC, Templifier™ Water Heater
•
•
•
•
Recovers waste heat
5,000 MBH to 24,000 MBH capacity
Hot water to 140°F
Refer to page 13
Model HSC, Heat Recovery Chiller
•
•
•
Recovers heat normally lost in cooling towers
Produces simultaneous cooling and heating
Refer to page 12
Special Applications
McQuay has the ability to design and manufacture special centrifugal compressor chillers with
unique design characteristics such as completely packaged, indoor or outdoor chiller plants, series
counterflow chillers, and others. Consult you local McQuay sales office.
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Wide Choice of Capacities and Efficiencies
The range of capacities and chiller types shown in the following chart gives the plant
designer the ability to pick and chose the exact capacity, optimum chiller type and
efficiency for either a single or multiple unit chiller plant. This flexibility is also a
tremendous asset for replacement chiller applications.
McQuay Offers the Widest Choice of ARI Certified, Ozone Safe Centrifugal Chillers
0
TONS
500
1000
1500
2000
2500
3000
Single Compressor Chillers
Single Compressor with VFD
Dual Compressor Chillers
Dual Compressor with VFD
Heat Recovery
Templifier Water Heater
Variable Chilled Water Flow
Tower Economizer Cycle
NOTE: The upper capacity limit for ARI certification on 60 Hz service is 2,000 tons, on 50 Hz service, the range is
703kW to 3516 kW. McQuay dual compressor chillers with or without VFD are available up to 2,500 tons.
MicroTech II® Controller Makes a Difference
Operator Interface Touchscreen
McQuay’s 12-inch super VGA touchscreen is truly “operator
friendly”. All important unit operating data is clearly
displayed and selectable at a touch of the screen. Setpoint
changes are easy to accomplish and to monitor, reducing
errors. Trend data of important parameters and alarm
history can be downloaded from a USB port located in the
adjacent unit control panel.
Easy BAS Integration
McQuay’s exclusive Protocol Selectability™ feature provides
a factory-installed communication module. You select
BACnet®, LONMARK® or Modbus® communications for
control and monitoring information to be sent to your BAS,
without the need for costly gateways.
BB
Distributed Control
Each chiller has a microprocessor controller for unit functions plus a separate microprocessor for
each compressor. Should the operator interface panel and/or the unit controller be unavailable,
the compressor controller(s) will maintain chiller operation, greatly increasing unit reliability.
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Customer Benefits Summary
All McQuay Distinction Series units offer the following benefits. See the additional
referenced pages for details.
Excellent Performance
It is important to choose a performance philosophy consistent with your application. McQuay has
a solution for your specific application. Contact your local McQuay sales office for computer
selections of chillers to match your requirements.
The following chart provides recommendations for the model choice for your application.
Application
McQuay Model
Cooling, most hours at full load
Cooling, most hours at part load
Heating application
Simultaneous cooling and heating
Optimized part load performance
WSC – Single compressor chiller
WDC – Dual compressor chiller
TSC – Templifier water heater
HSC – Heat recovery chillers
Variable frequency drive options
Sustainable Performance
Although frequently overlooked, an important point to consider when selecting a chiller is the
sustainability, over time, of the original purchased performance. All McQuay centrifugal chillers
are positive pressure design, using R-134a refrigerant (the first manufacturer to do so) and the
chiller performance is sustainable for the life of the unit. On the other hand, chillers using R-123,
with negative pressure designs, will loose capacity as air and moisture seep into the refrigeration
system. As the volume of air and moisture increases, the performance penalty increases. For
example, if a negative pressure design chiller is purchased at 0.58 kW/ton, with the assumption of
100% refrigerant in the unit, the performance, with a 3% penalty for air and moisture
contamination, will deteriorate to 0.60 kW/ton. The owner will not be receiving the purchased
efficiency. With McQuay’s positive pressure design, there is no penalty for non-condensables
entering the unit.
R-134a Refrigerant
All McQuay centrifugal chillers use R-134a instead of R-123 refrigerant, which is still being used
by a few manufacturers. R-134a offers the following distinct customer benefits.
Positive Pressure Design
R-134a chillers operate with the entire system above atmospheric pressure at all times. In the
event of a small leak, refrigerant escapes from the chiller to the atmosphere, which allows easy
detection and repair. With R-123, air leaks into the system, making leak detection and repair a
difficult task.
No Purge Unit
Even with the best and newest purge units, some refrigerant will be discharged to the atmosphere.
Purge units, with their compressor, tanks and piping can be high maintenance components.
No Annual Lubricant Maintenance
Annual oil maintenance is required with low-pressure designs, increasing owning cost. When air
and moisture seep into a negative pressure machine, the acid and corrosion that can form must be
removed periodically. McQuay’s positive pressure design does not require this maintenance.
Under normal operation, the oil charge and filter are good for the life of the unit!
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No Vessel Heating Blankets
When negative pressure chillers are expected to be inoperative for a long period of time, during
winter shutdown for example, it is common to apply an electric heating blanket to the evaporator
in order to raise the refrigerant pressure above atmospheric. In other words, try to force it to
behave like a McQuay R-134a unit! The initial and operating costs of these blankets are not
necessary with a McQuay chiller.
No Refrigerant Availability Issue
R-134a is considered a solution to refrigerant environmental issues because it does not have a
phase-out date. R-123 cannot be used in new equipment after the year 2020. History has shown
us that a practical refrigerant phase out occurs well in advance of the Montreal Protocol’s
mandate. Since R-123 has been primarily used only in chillers and only since 1995, there is a
limited quantity available for recycling to meet service needs to 2030. It is already capped in the
United States and will be reduced to 0.5% by 2020 for service use only until 2030. It is
considered highly unlikely that the phase out dates will be extended.
Lower Health Risk with McQuay’s R-134a
R-134a is listed as an “A1” refrigerant as defined by ASHRAE Standard 15, which means that it
has the lowest toxicity and flammability rating. R-123 is rated as “B1”, which means it is toxic to
humans and also carries a low flammability rating. In the event of a refrigerant release, the
likelihood of personnel risk is lower with R-134a.
Smaller Equipment Rooms
As a general rule, the physical size of an R-134a positive pressure chiller will be smaller than a
negative pressure chiller, reducing equipment room size. R-123 requires a much larger refrigerant
flow rate than R-134a, with a subsequent increase in component size. Also, Equipment room
ventilation requirements are greatly reduced when compared to chillers with open drive motors,
which reject heat directly into the room ambient air.
Gear Drive Advantage
Lower Vibration
A gear-driven compressor runs at higher impeller rotational speeds but tends to have less vibration
than the larger, much heavier, direct drive units. All McQuay compressors must pass a stringent
vibration test while running on the production test stands. Spring isolators are normally not
required for most applications.
Unique Lubrication System
With the higher rotational speeds and much lighter running components compared to direct drive
units, efficient hydrodynamic bearings can be used. The shafts are supported on a film of
lubricant, rather than running with metal-to-metal contact, typical of rolling element bearings.
Under normal circumstances, the McQuay bearings have a theoretical infinite life while rolling
element bearings do not.
Selectable Impeller Speeds
Another gear drive advantage, over the older design direct drive units, is the ability to select gear
ratios that will provide the optimum impeller tip speed for a given application. Impeller speeds
can be selected to provide sufficient pressure lift ability without the excessive tip speeds that lead
to inefficient compressor operation.
Also, the gear options allow for excellent compressor performance on 50 Hertz power.
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Catalog WSC/WDC-4
Unmatched Unloading
McQuay’s Distinction Series chillers offer unloading to 10% of full load for a WSC single
compressor chiller and 5% for a WDC dual compressor units, without using inefficient hot gas
bypass. This unloading capability, unique in the industry, provides improved stability of the
chilled water temperature and less harmful cycling of compressors. There are significant reasons
for this beneficial operating characteristic, including:
Moveable Diffuser
McQuay has pioneered the use of moveable discharge geometry to lower the surge point of
centrifugal compressors. The point at which the compressor enters a stall or surge condition
generally limits compressor unloading. At low loads, low gas velocity through a fixed discharge
area results in low gas velocities and the gas can stall or
surge in the impeller. When in a stall condition, the
refrigerant gas is unable to enter the volute due to its low
velocity and remains stalled in the impeller. In a surge
condition the gas rapidly reverses direction in the impeller
causing excessive vibration and heat. McQuay compressors
reduce the discharge area as load decreases to maintain gas
velocity and greatly reduce the tendency to stall or surge.
See page 27 for a complete description.
Moveable diffuser closing off impeller discharge area
Thermal Expansion Valve
Pilot expansion valve
Main expansion valve
There are three refrigerant control devices used in the
industry, expansion valves, fixed orifices, and float
systems. Of the three, only expansion valves, (electronic
up to 300 tons and thermal over 300 tons) as used by
McQuay, offer good refrigerant management throughout
the entire chiller operating range. Expansion valves help
the McQuay chillers achieve their industry leading
capacity reduction capability.
Quiet Operation
McQuay chillers have two unique features to limit sound generation. One is the unique liquid
injection system and the other is that McQuay chillers get quieter as they unload.
Liquid Injection
A small amount of liquid refrigerant is taken from the
condenser and injected into the compressor discharge area.
The liquid droplets absorb sound energy and reduce the
compressor’s overall sound level. The droplets evaporate
and reduce discharge superheat.
Radial ports inject liquid refrigerant into the
discharge gas as it enters the volute.
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7
Quieter as Chiller Unloads
Many centrifugal compressors become louder as they unload. McQuay’s design results in a
reduction in sound levels at lower loads, where most chillers spend most of their operating hours.
Power Loss Damage Protection
Unfortunately, loss of electric power without
allowing chillers to proceed through their normal
shutdown sequence is becoming common in
many areas. When this occurs, most compressors
must coast to a stop without benefit of their
lubricant pump running. Poor lubrication at this
point can damage the bearings and reduce
compressor life.
McQuay compressors are
equipped with a lubricant reservoir and a piston
with a compressed spring that provides
pressurized lubricant to the bearings during the
coast-down period. Also, the compressors
decelerate quickly due to the low inertia.
Piston and spring
Lubricant reservoir
Refrigerant Storage Capability - Standard
The condensers on McQuay Distinction Series chillers are
sized to hold the entire chiller refrigerant charge and are
provided with the necessary valves to isolate this charge. This
feature eliminates the need for separate storage vessels in most
applications.
Discharge line
check valve
combines with
main liquid shutoff
valve to isolate
the condenser
McQuay Startup
All McQuay centrifugal chillers are commissioned by McQuay Factory Service personnel, or by
authorized and experienced McQuay startup technicians. This procedure helps assure that proper
starting and checkout procedures are employed and helps in a speedy commissioning process.
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Catalog WSC/WDC-4
WDC, Dual Compressor Chillers
One WDC Dual Compressor Chiller
= Two Single Compressor Chillers
Lower equipment costs than two separate chillers
Lower installation cost than two separate chillers
Lower annual operating cost than either one large or two small chillers
Less equipment room space required than for two separate chillers
Capacity reduction to 5% of design cooling tons
Standby redundancy for most of the cooling season
Greatly reduced starting load for emergency standby power plants
Industry Leading Efficiency
When coupled with McQuay's variable frequency drive, the extremely efficient Dual Compressor
Chillers become the most efficient chillers available in the market place with IPLVs in the low
0.3s kW per ton. IPLV conditions are set by ARI and subject to stringent testing. Insist on ARI
certified IPLV efficiency when making comparisons.
The Redundancy Feature
The McQuay dual centrifugal chillers have two of everything, connected to a common evaporator
and condenser - two compressors, two lubrication systems, two control systems, two starters.
If any component on a compressor system fails, the component can be removed or repaired
without shutting down the other compressor; providing an automatic back-up with at least 60
percent of the chiller design capacity available.
In the unlikely event of a motor burnout, the chiller refrigerant charge will not be contaminated.
This is so well proven that it is guaranteed for five years. Contact the local McQuay sales office
for details. In areas supported by McQuay Factory Service, if a motor burnout contaminates the
refrigerant in the chiller, the charge will be replaced free for a period of five years from start-up.
60 Percent Capacity on One Compressor
When one compressor is running, it is able to utilize the heat transfer area of the entire chillertwice the amount found on a single compressor chiller. This huge amount of surface provides
exceptional part load efficiency and lets a single compressor operate at 60 percent of the entire
unit capacity. In most building, this will carry the load most of the time.
Catalog WSC/WDC-4
9
Why a Compressor Motor Failure Will Not Contaminate the Common
Refrigerant Circuit
The compressor motor is isolated from the main refrigerant flow circuit so that any contaminants
generated by a motor failure will not pass into the main refrigerant circuit. Moisture, acid and/or
carbon particles will be automatically trapped within the compressor’s dedicated coolant feed and
exit lines.
Internally, the compressor motor compartment is separated and sealed from the main refrigerant
compression chamber. A double shaft seal on the motor side of the gear housing prevents cross
flow of refrigerant along the motor shaft. The motor coolant feed line is equipped with both a
solenoid valve and a check valve. These mechanical components, plus the higher pressure of the
liquid refrigerant, prevent back feed into the main refrigerant system. Refrigerant vapor exiting
the motor compartment must pass through a high pressure drop filter-drier. The filter-drier is
sized to immediately plug up and seal off the motor compartment. Both the coolant feed and
return lines are equipped with manual shutoff valves to permit component service.
Over 30 years of field experience have proven the reliability of these compressor motors. Despite
the reliability inherent in the motor design and the protective control, electrical distribution
system faults and lightning strikes can occur that are beyond the control of the most conscientious
designer. The McQuay motor coolant protective system protects the unit refrigerant charge from
being contaminated.
Figure 1, Motor Cooling
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Catalog WSC/WDC-4
Part Load Efficiency
Chillers usually spend 99% of their operating hours under part load conditions, and most of this
time at less that 60% of design capacity. One compressor of a dual chiller operates with the full
heat transfer surface of the entire unit. For example, one 500-ton (1,750 kW) compressor on a
1,000 ton (3,500 kW) dual chiller utilizes 1,000 tons (3500 kW) of evaporator and condenser
surface. This increases the compressor’s capacity and also results in very high efficiency.
Typical efficiencies for a dual compressor chiller, taken from a selection computer run, look like
this:
•
Full load efficiency
0.550 kW per ton (6.5 COP)
•
60% load, one compressor
0.364 kW per ton (9.6 COP)
•
IPLV
0.415 kW per ton (8.5COP)
The addition of VFDs to the dual compressor chiller produces an astonishing ARI certified IPLV
of 0.340 for the above case. Specific selections can vary up or down from this example. IPLV is
defined in the Selection section of this manual beginning on page 41.
Lower Installed Costs
The redundancy feature pays off in lower installed costs
An example of how to incorporate dual compressor chillers into a system requiring redundancy:
Job requirement:
1,200 tons (4200 kW), 50% Backup
Dual Compressor Chillers
Single Compressor Chillers
(2) 600 ton (2100 kW) On Line Units
(2) 750 ton (2100 kW) Units with
+(1) 600 (2100 kW) ton Standby Unit
1,200 (4200 kW) On Line tons *
(3) @ 1,800 ton (6300 kW) Installed Capacity
(2) @ 1500 ton (5250 kW) Installed Capacity
* One 750-ton (2100 kW) dual chiller running on two compressors for 750 tons (2100 kW), plus
one 750-ton (2100 kW) dual chiller running on one compressor for 60% of 750 tons (2100 kW) =
450 tons (1575 kW), for a total of 1200 tons (4200 kW) on any 3 of the 4 total compressors.
The elimination of the extra pumps, valves, piping, controls, rigging, and floor space can result in
as much as a 35% reduction in the installation cost for a chiller plant, plus the savings on the
chillers themselves.
The Replacement Market Advantage
•
Bolt-together construction on single and dual compressor chillers
•
Put 20% or more tons in the same footprint
•
Add dual compressor redundancy
•
Greatly reduce chiller energy consumption
•
Install a refrigerant with no phase-out date
•
Opens many options for multiple chiller plants
Catalog WSC/WDC-4
11
Heat Recovery Models
For decades, McQuay International has pioneered the use of heat recovery chillers and the unique
McQuay Templifier™ Heat Pump Water Heater to reduce energy costs. These products have
become more important than ever with the current emphasis on total building efficiency.
ASHRAE Efficiency Standard 90.1 mandates the use of heat recovery equipment of this type in a
wide range of buildings.
Heat Recovery Chillers
The heat recovery chillers, Models HSC with a single
compressor, have a single condenser with split bundles, i.e.,
two separate water passages divided by separate water heads
as shown in the photograph to the right. The inboard water
connections are connected to the cooling tower, the other
water side is connected to the heating system.
The economic feasibility of hot water generated with these
units depends on heating and cooling load profiles and on
the relative cost of the available energy sources. A
compressor’s kw per ton is heavily influenced by the
pressure head it is pumping against. During heat recovery
operation, all of the cooling load is operating against the
high head required by the hot water temperature. For this
reason, it is desirable to maximize the percentage of the total
rejected heat used for the heating load.
McQuay’s economic evaluation program, Energy Analyzer™, available on CD from your local
McQuay sales office, is the perfect tool to determine the economic feasibility of using this proven
technology.
Figure 2, Heat Recovery Chiller Piping Schematic
HEAT LOAD
AUXILIARY
HEATER
OPEN
CIRCUIT
TOWER
TC
RECOVERY
CONDENSER
TOWER
CONDENSER
HEAT RECOVERY
CHILLER
TC
LEGEND
TC TEMPERATURE CONTROL POINT
EVAPORATOR
PUMP
COOLING
LOAD
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Catalog WSC/WDC-4
Templifier™ Heat Pump Water Heaters
Model TSC, 3,000 to 24,000 MBH (880 to 7,000 kW) Heating Capacity
The Model TSC Templifier was
developed in the 1970s, after
the 1973 oil embargo, as a
device to replace fossil-fired
COOLING
TOWER
SUPPLEHEATING
water heaters with electric
MENTAL
LOAD
HEATER
heaters.
The concept was
135°F
125°F
simple;
direct
a stream of warm
(57°C)
(52°C)
waste heat to the evaporator of
CONDENSER
a refrigeration unit, amplify the
temperature of the heat through
90°F
95°F
85°F
(32°)
(35°C)
(29°C)
the compression cycle, and then
EVAPORATOR
CONDENSER
deliver the heat from the
TEMPLIFIER HEAT
PUMP WATER HEATER
condenser, at a higher useful
55°F
45°F
(7°C)
(13°C)
temperature, to a heating load.
EVAPORATOR
TC
TC
The flow diagram shown to the
left illustrates just how the
Templifier unit is placed in a
chilled water system.
The
COOLING
LOAD
decision to include a Templifier
water heater is almost always a
financial one. Evaluation of load profiles, energy costs, and owning costs is made simple by using
the McQuay Energy Analyzer™ evaluation program to determine if the return on investment
meets the owner’s requirements.
When there is sufficient waste heat available, Templifier units can be very attractive where fossil
fuels are not available, or where their use is restricted due to pollution problems or other reasons.
Compared to electric resistance heating, the energy cost for a Templifier unit to heat domestic
water, for example, could be 7 to 8 times less!
CHILLER
TC
TEMPERATURE CONTROL
Where to Use Templifier Water Heaters
Typical Building Types
Hotels/Motels
Schools
Health Care
Food Service
Athletic Facilities
Nursing Homes
Resorts
Typical Applications
Space Heating
Service Hot Water
Outside Air Heating
Laundries
Reheat
Kitchens
Typical COPs
Hot Water Temperatures
110°F
120°F
130°F
140°F
COP (Based on 85°F off Chiller to Templifier)
8.3
6.8
6.0
4.5
The Templifier Water heater has also found innumerable applications in industries such as food
processing, recovering waste heat and supplying hot process water, as high as 140°F, at high COPs
and low cost. See the McQuay PM Templifier catalog for additional information.
Catalog WSC/WDC-4
13
Typical Templifier Applications
Service Hot Water Piping
OUTPUT
140°F
(60°C)
Intermediate Heat Exchanger
Ground Water Heat Source
RETURN /
MAKEUP
STORAGE
TANK
140°F
(60°C)
STANDBY /
AUXILIARY HEAT
140°F
(60°C)
T-C
CONDENSER
EVAPORATOR
TEMPLIFIER
HEAT
SOURCE
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Catalog WSC/WDC-4
Control Features
®
Chillers Feature MicroTech II Controls
McQuay has incorporated the latest microprocessor technology into the MicroTech II control
system to give you the ultimate in chiller control. The control includes many energy-saving
features to keep your chiller running efficiently . . . day in, day out, for years to come.
Figure 3, Unit Controller and Operator Interface Touch Screen
The unit controller and operator
interface touchscreen mounted on a
chiller unit are shown to the right.
The 12-inch VGA touch screen is
on an adjustable arm so that it can
be positioned comfortably for each
operator.
The control panel
contains a USB port from which
trend data and manuals can be
conveniently downloaded. Allimportant unit operating data is
easily accessed and viewed.
Password protected unit setpoints,
complete with description and
setting range, are available at the
touch of a screen.
Figure 4, Compressor Controller
A major feature of the
MicroTech II controller, as
applied to chillers, is the
distributive control scheme. The
picture to the right shows the
compressor control panel (with
cover removed) mounted at the
rear of the unit, adjacent to the
compressor itself. This panel
also contains the oil pump
contactor and overload. Model
WDC dual compressor chillers
have two such panels. Also on
the pLAN (control network) is
the unit controller and operator interface touch screen. If the interface touch screen and/or unit
controller is out of service, the chiller can continue to operate on the compressor controller alone.
This feature provides unprecedented reliability in a chiller control system.
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15
MicroTech II Features and Benefits
FEATURE
BENEFIT
Easy integration into a building management
system via McQuay’s exclusive Protocol
Selectability™ feature.
Designer can to select any BAS supplier using
industry standard protocols and know the
MicroTech II control will easily interface directly
with it.
Easy to read, adjustable, 12-inch, Super VGA
color touchscreen operator interface
Operators can observe chiller operation at a
glance, easily select various detail screens and
change setpoints
Historic trend data-can be downloaded from
a USB port
Water temperatures, refrigerant pressures, and
motor load plots can provide valuable unit
operation data
Precise ± 0.2 °F chilled water control
Provides stability in chilled water system
Proactive
pre-shutdown
correction
of
“unusual conditions” allows chiller to stay
online
Activates alarm and modifies chiller operation
to provide maximum possible cooling
Automatic control of chilled water and
condenser water pumps
Integrated lead/lag and automatic engagement
of backup pump
Controls up to four stages of tower fans and
modulation of tower fan and/or bypass valve
Optimum integrated control of cooling tower
water based on system conditions
Twenty-five previous alarm descriptions are
stored in memory
Invaluable asset in troubleshooting
Multiple language capability
Metric or in-lb units of measure
Great asset for world-wide applications
Designed with the System Operator in Mind
Reliable, economic use of any chiller depends largely on an easy operator interface. That’s why
operation simplicity was one of the main considerations in the development of the MicroTech II
controller. The operator interface with the chiller is a 12-inch, Super VGA color touch-screen.
The operator can clearly see the entire chiller graphically displayed, with key operating parameters
viewable on the screen. Other screens, such as alarm history and set points, are easily accessed
through touch screen buttons.
We have even gone as far as installing the unit operating and maintenance manual, as well as the
parts list, in the chiller’s microprocessor memory, so that they are viewable on the touchscreen or
can be downloaded to a computer through the onboard USB port.
Proactive Control
By constantly monitoring chiller status, the MicroTech II controller will automatically take
proactive measures to relieve abnormal conditions or shut the unit down if a fault occurs. For
example, if a problem occurs in the cooling tower and discharge pressure starts to rise, the
controller will automatically hold the load point and activate an alarm signal. A further rise in
pressure will initiate compressor unloading in an effort to maintain the setpoint pressure. If the
pressure continues to rise, the unit will shut off at the cutout pressure setting.
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Catalog WSC/WDC-4
Alarm History for Easy Troubleshooting
The MicroTech II controller's memory retains a record of faults and a time/date stamp. The
controller's memory (no batteries required) can retain and display the cause of the current fault and
the last twenty-five fault conditions. This method for retaining the fault is extremely useful for
troubleshooting and maintaining an accurate record of unit performance and history.
The MicroTech II controller features a three-level password security system to provide protection
against unauthorized use.
Figure 5, MicroTech II Controller Home Screen
The Home Screen shown above is the primary viewing screen. It gives real time data on unit
status, water temperatures, chilled water setpoint and motor amp draw. This display answers the
vital question-is the chiller doing what it is supposed to be doing?
If an alarm occurs, a red button
appears on the screen (a remote
signal is also available). Pressing
this button accesses the Active
Fault Screen that gives complete
fault information. The fault can be
quickly and easily cleared at this
point.
Changing Setpoints
Changing setpoints is easy with
the McQuay MicroTech II control.
For example, to change the chilled
water set point, press SET from
any screen, then press the WATER
button and this screen appears,
press button #1, Leaving Water
Temperature, and you are ready to
input a password and then a new value.
Catalog WSC/WDC-4
17
Trend Logging
Ever wonder how your chiller
performed last week? Were
you holding the correct
chilled water temperature?
What kind of cooling load did
the chiller have?
The McQuay MicroTech II
controller can provide the
answers, thanks to its huge
memory, and plot water
temperatures,
refrigerant
pressures, and motor load
data. These values can also
be downloaded through a
convenient USB port, located
in the unit control panel, and
pasted into a spreadsheet for
archiving or further detailed
evaluation.
MicroTech II Controller Increases Chiller Operating Economy
Many standard features have been incorporated into MicroTech II control in order to maintain the
operating economy of McQuay centrifugal chillers. In addition to replacing normal relay logic
circuits, we’ve enhanced the controller's energy saving capabilities with the following features:
• Direct control of water pumps. Optically isolated, digital output relays provide automatic
lead-lag of the evaporator and condenser pumps, permitting pump operation only when
required.
• User-programmable compressor soft loading. Prevents excessive power draw during pull
down from high chilled water temperature conditions.
• Chilled-water reset. Accomplished directly on the unit by resetting the leaving water
temperature based on the return water temperature, a remote 4-20 ma or a 1-5 VDC BAS
signal. Raising the chilled water setpoint during periods of light loads dramatically reduces
power consumption.
• Demand limit control. Maximum motor current draw can be set on the panel, or can be
adjusted from a remote 4-20ma or 1-5 VDC BAS signal. This feature controls maximum
demand charges during high usage periods.
• Condenser water temperature control. Capable of four stages of tower fan control, plus an
optional analog control of either a three-way tower-bypass valve or variable speed tower-fan
motor. Stages are controlled from condenser-water temperature. The three-way valve can be
controlled to a different water temperature or track the current tower stage. This allows
optimum chilled water plant performance based upon specific job requirements.
• Staging Options (Multiple Chiller Installations). The MicroTech II controller is capable of
compressor staging decisions and balancing compressor loads between McQuay chillers using
defaults or operator-defined staging.
• Plotting Historic Trends. Past operation of the chiller can be plotted as trend lines and even
downloaded to spread sheets for evaluation - a valuable tool for optimizing efficiency.
18
Catalog WSC/WDC-4
Starter Data Displayed
As standard, the percent of rated load amps (RLA) is displayed on the interface screen as a bar
chart. In addition, there are two options available to display additional starter data on screen. The
options are:
• Ammeter Display, which displays phase amps and average amps
• Full Metering Display, which displays phase and average amps, phase and average volts,
compressor kilowatts, power factor and unit kilowatt-hours.
These options, in particular the full metering option, give the owner/operator a great deal of
valuable electrical information in an easily accessed screen.
WDC Chiller Controls
Each model WDC dual compressor chiller comes complete with its own factory-mounted and
wired MicroTech II controller system featuring:
•
12-inch color touchscreen operator interface panel
•
Microprocessor-based unit controller
•
Microprocessor-based controller for each compressor
This distributed control scheme allows the operation of each compressor independently from the
other. Elapsed time, number of starts, percent RLA; are all monitored separately by each
MicroTech II control panel. In addition, individual compressor fault history, setpoint control,
loading functions, time of day starts, etc., can be controlled and monitored.
Compressor staging and the load balance function are a standard feature of each MicroTech II
control. Smart scheduling starts the compressor with the fewest number of starts first, and will
only start remaining compressors when proof of sufficient load has been established. The staging
function will stop the compressor with the most run-hours when the load decreases to single
compressor range. During two-compressor operation, the load balance function will equalize the
load between each compressor, providing optimum unit efficiency.
25% or greater annual kWh savings over the range of 5% to 60% design tons
The majority of comfort cooling systems operate at 60% or less of building design tons for most
of the year. A great number of those operating hours occur between 50% and 60% design cooling
capacity.
For that reason, the Model WDC chiller was designed to produce up to 60% unit capacity with a
single operating compressor, efficiently and reliably.
That performance is achieved by a combination of individual component features that include
compressor design, operating control, double heat transfer surface, and refrigerant flow control.
Versatile Communications Capabilities Give You Even More Control
For complete flexibility there are three ways to interface with the MicroTech II controller:
1. Direct entry and readout locally at the controller's operator interface panel on the unit.
2. Direct entry as above, plus digital and analog input/output signals for certain functions such as
enable run input, alarm signal output, 4-20ma or 0-5 VDC inputs for chilled water reset and
load limiting, outputs for pump and tower fan control, analog output for variable speed tower
fan and/or tower bypass valve.
3. Interface with a building automation system (BAS) with optional factory-installed Protocol
Selectability™ communication modules, eliminating additional gateways. The module can
also be field installed anytime after the unit is installed and operating.
Catalog WSC/WDC-4
19
Multiple Chiller Control
McQuay’s standard MicroTech II control system, as shipped on all units, will control up to three
chillers, either single or dual compressor type. A simple RS 485 interconnection and minor set
point adjustments are all that is required. When a chiller system will have more than three
chillers, McQuay has a flexible and reliable chiller manager available.
Chiller System Manager (CSM)
Application
•
•
•
•
•
Two sizes available, up to 6 chillers or up to 12 chillers
Two voltages available, 120 VAC or 240 VAC, for world-wide application
Control chillers in series and/or parallel
Flexible chiller sequencing of constant volume primary/secondary or primary only systems
Stand-alone control or easy integration with your choice of third party BAS with open,
standard protocols
Benefits
•
•
•
•
•
Flexibility to accommodate most chiller sequencing schemes for improved system efficiency
and reliability
Single source responsibility for chillers and chiller management system startup
Reduced commissioning and installation cost
Graphical-based application is easy for operators to learn and use
Scalable platform can grow as the chiller system expands
Capabilities
•
•
Flexible, dedicated or common tower control
Chilled water control options, variable or constant speed, lead/standby control, loop bypass
valve control
• Graphical scheduling including weekdays/weekends, special events, can use external input
• Password protection
• Load limiting
• Choice of chilled water reset schemes
• Inhibited stage up based on time-of-day or BAS input
• Annunciation, display, logging, and acknowledgement of chiller and system alarms
Figure 6, Typical Display for Three Chiller Setup
20
Catalog WSC/WDC-4
Building Automation Systems
All MicroTech II controllers are capable of communications, providing seamless integration and
comprehensive monitoring, control, and two-way data exchange with industry standard protocols
such as LONMARK®, Modbus® or BACnet®.
Protocol Selectability™ Benefits
•
Easy to integrate into your building automation system of choice
•
Factory-installed and tested communication module
•
Comprehensive point list for system integration, equipment monitoring and alarm notification
•
Provides efficient equipment operation
•
Owner/designer can select the BAS that best meets building requirements
•
Comprehensive data exchange
Integration Made Easy
McQuay unit controllers strictly conform to the interoperability guidelines of the LONMARK®
Interoperability Association and the BACnet Manufacturers Association. 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.
Catalog WSC/WDC-4
21
Table 1, Typical Data Point Availability
Typical Data Points1 (W = Write, R = Read)
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
R
R
R
W
W
R
R
R
W
R
R
R
R
R
W
R
R
Cond EWT
Cond Flow Switch Status
Cond LWT
Cond Pump Run Hours
Cond Refrigerant Pressure
Cond Sat. Refrigerant Temp
Cond Water Pump Status
Cool Setpoint
Current Alarm
Default Values
Evap EWT
Evap Flow Switch Status
Evap LWT for Unit
Evap LWT for Compressor
Evap Pump Run Hours
Evap Refrigerant Pressure
Evap Sat. Refrigerant Temp
R
R
R
R
R2
R2
R
W
R
W
R
R
R
R
R
R2
R2
Evap Water Pump Status
Heat Recovery EWT
Heat Recovery LWT
Heat Setpoint
Ice Setpoint
Liquid Line Refrigerant Pressure
Liquid Line Refrigerant Temp
Maximum Send Time
Minimum Send Time
Network Clear Alarm
Oil Feed Pressure
Oil Feed Temp
Oil Sump Pressure
Oil Sump Temp
Outdoor Air Temp
Pump Select
Run Enabled
R
R
R
W
W
R
W
W
W
R
R
R
R
W
R
Notes:
1. Data points available are dependent upon options selected
2. Per compressor
Figure 7, Sample System Architecture
Open standard
protocol network
such as LonTalk,
Modbus or BACnet.
MicroTech II
Air Cooled Chiller
System
Control
Panel
Lighting
Control Panel
by Others
Building Automation
System of Your Choice!
VAV Boxes by Others
MicroTech II Unit Ventilators
Alerton, Automated Logic, Delta Controls,
Honeywell, Invensys, Johnson Controls,
Siemens, TAC … And more
Field Level Devices by Others
MicroTech II Centrifugal Chiller
22
Catalog WSC/WDC-4
Unit Design Features
Compressor Design
Gear-Drive Offers Greater Operating Efficiency Than Direct Drive
Centrifugal compressor efficiency is a function of impeller design and application to the
refrigeration system. The increased heat transfer surface and efficiency of modern heat
exchangers have changed compressor head and impeller tip speed requirements. Direct-drive
designs limit the manufacturer’s ability, within a single compressor size, to select impellers at or
near peak impeller efficiency. While a unit selected at poor impeller efficiency might produce the
required performance at peak load, its operating characteristics over the entire range of part load
performance are sharply curtailed, resulting in increased annual operating costs.
McQuay gear-drive centrifugal chillers provide a variety of tip speed ratios to permit selection of
impellers for maximum efficiency over their entire part load to full load range and are also ideal
for 50 Hz application. Mechanical gear losses are limited by design standards to less than onehalf of 1%. The impeller efficiency obtained by alternate gear selections can increase chiller
efficiency by as much as 7%.
As energy costs continue to rise, the economic advantages of gear drive to obtain maximum
efficiencies will be even more advantageous. The efficiency of either direct-drive or gear-drive
compressor can be improved through the use of variable frequency drives to reduce compressor
speed at low load/low head conditions.
Extended Motor Life
McQuay’s modern compact compressor design provides many operating advantages that improve
its overall reliability and durability. One such advantage is prolonged motor life. A motor draws
locked rotor current until it reaches break-away torque at approximately 80% of its running speed.
While drawing locked rotor current, the stresses on the motor are over six times that of full load.
The McQuay compressors absolutely minimize this stress through the unique gear drive and light
weight drive train that allows a 500-ton (1750 kW) compressor to reach running speed in less than
three seconds. The owner benefits from a longer motor life.
The REAL FACTS on Speed, RPM and Tip Speed in Centrifugal Compressors
The question: "How fast does it spin?" is common when discussing compressors. There is a
widespread concept that the impeller rotating speed (rpm) is the determining factor in the life,
reliability, and efficiency of the compressor. This is absolutely false. An engineering examination
will show that rpm, as an absolute, is not considered in the design of rotating mechanical
components. It is the combination of velocity of the outside edge of the impeller (tip speed),
mass, and physical size that define the design criteria for these components. Shaft, bearing, and
impeller design is based on parameters such as surface velocity, diameter, weight, rotational and
torsional critical speed, as well as the type of material and lubrication system used.
Stress on an impeller is proportional to the square of the tip speed. Rotational speed is only
part of the equation along with impeller diameter.
In centrifugal compressor design, two parameters, impeller diameter and impeller tip speed, must
be determined. Impeller diameter is determined by the required volume flow rate supplied to the
inlet of the impeller. Refrigerants which operate at a negative pressure such, as HCFC-123 have
high cfm/ton (m3/kW) flow rates and require larger diameter impellers and refrigerant lines to
keep pressure drop to reasonable levels.
Catalog WSC/WDC-4
23
Systems with refrigerants that operate at a positive pressure, such as R-134a, have smaller
impellers and gas lines since these refrigerants require lower gas flow rates. R-123 requires
approximately six times the gas flow rate in cfm per ton than R-134a. At ARI standard conditions,
18.1 cfm (8.54 l/sec) of R-123 is required per ton of refrigeration. Contrast this to R-134a that
requires only 3.2 cfm (1.5 l/sec) per ton. This means that for a given capacity, the cross-sectional
area of the impeller inlet "wheel eye" as well as the suction and discharge lines will be six times
larger for R-123 than for R-134a at equivalent pressure drops. The wheel eye diameter is the
major factor in determining the overall impeller diameter and geometry.
Designers of centrifugal equipment must also consider the tip speed requirement. To produce the
required pressure difference or lift, a centrifugal impeller must achieve a given tip speed. Tip
speed is the velocity of the "tip" of the impeller relative to its surroundings. Imagine an observer
standing on the impeller. The observer sees his surroundings pass by him at a certain velocity.
This velocity is the impeller tip speed, usually expressed in feet per second (meters per second).
An analogy can be drawn to a car driving down a road. The tip speed of the tire is equal to the
speed of the car.
Since all the refrigerants that have been discussed require tip speeds in the range of 670 to 700
ft/sec (204 to 213 m/sec), we see that the impeller angular velocity (rpm) is largely affected by its
diameter. It was pointed out earlier that negative pressure impellers must be larger than those in
positive pressure machines due to the drastic differences in required gas flow rates. Larger
diameter impellers must rotate at slower rpm than smaller diameter impellers. Referring again to
the car example demonstrates that different combinations of diameter and rpm produce the same
tip speed. Imagine a freeway carrying vehicles with different size tires all traveling at 55 mph.
The tip speed of all of the tires is fixed at 55 mph even though the small tires of a utility trailer
rotate at a much higher rpm than the tires of a tractor-trailer.
The relationship of diameter and tip speed can be shown by the following equation:
RPM = [TipSpeed ( fps ) x 229.2] / Diameter (in.)
RPM = [TipSpeed (m / s ) x1910] / Diameter (cm.)
Again, this indicates that for a given speed requirement, a smaller diameter impeller in a
compressor will operate at a higher rpm than a larger diameter impeller. Again:
Stress is proportional to the tip speed2: Impellers with similar tip speeds have similar stress.
Quiet, stable capacity from 10% to 100% without hot gas bypass
Compressor capacity on McQuay chillers is maximized at full load and modulated to 10% load by
interlocked inlet guide vanes and the movable discharge geometry. This McQuay design
innovation has real owner benefits. Most centrifugal compressors do not unload this well and
waste energy at low load conditions by unnecessary compressor cycling or by the use of
inefficient hot gas bypass.
No leakage at the capacity control mechanism
An oil pressure operated, guide vane activating piston is internally mounted and powered,
eliminating leakage from external linkage and seals. The vanes are positioned in response to
variation in leaving chiller water temperature. A built-in compensating control allows automatic
override of normal operation to close the vanes for low suction pressure or current limiting duty.
24
Catalog WSC/WDC-4
Figure 8, HFC 134a Impeller Compared to R-123 Impeller
Left: Impeller from a McQuay single stage
300 ton (1050 kW) compressor; diameter =
6.3 in. (16 cm), weight = 3.0 lb (1.4 kg)
Right: One of three impellers from a 300
ton negative pressure compressor; diameter
= 26 in. (66 cm), weight = 27 lb. 12.2 kg)
Single Stage Simplicity = Savings
Compressor efficiency is not a function of multiple impellers. Maintenance of optimum
efficiency at peak and, more importantly, at part load, is a function of the total compressor and
chiller design including:
• Motor efficiency
• Refrigerant type
• Condenser and evaporator surfaces
• Compressor mechanical friction
• Impeller and vane design
• Refrigerant flow passages
Of these, the least considered performance factor on actual versus theoretical performance is the
refrigerant flow passages between the discharge of one impeller and the inlet to the next impeller
on multi-stage machine design. The energy loss in a single passage will be greater or equal to the
loss in the suction passage between the evaporator outlet and the first stage impeller inlet,
depending upon the compactness of the total compressor design. Single stage impeller design can
eliminate that additional loss, and provides an opportunity for maximum system efficiency.
The primary advantage to multi-stage centrifugal operation, in the pressure and volume ranges
characteristic of typical air conditioning systems, is the expansion of impeller head coefficients at
reduced volumetric flows or cooling loads. The McQuay backward inclined single stage impeller,
combined with unique movable diffuser geometry at the impeller discharge, provides a stable
operating range superior to multi-stage systems. Thus, selection of McQuay chillers permits
operation from 100% to 10% capacity (to 5% on WDC dual compressor chillers) without surging
and at maximum efficiency, i.e. no hot gas bypass.
Optimum compressor efficiency is designed into each McQuay impeller. The McQuay designed
impeller not only minimizes pressure loss at the inlet and maximizes compression efficiency, but
also breaks up pure tone sound to operate at competitively low sound power levels. A simple
short diffuser and a volute design passing compressed gas directly into the condenser maintain
the compressor efficiency.
Catalog WSC/WDC-4
25
Figure 9, McQuay’s million-dollar compressor test stand with advanced data acquisition
provides comprehensive information on new compressor designs.
Bearings
Since the impeller shaft must be sized to support the static, rotational and torsional loads applied
by the impeller, as impellers become larger, shafts must also become proportionally larger. These
factors also come into play in the design or selection of a bearing. The primary criteria used in
bearing design are:
1. The load-per-unit of bearing area.
2. The relative velocity of the two bearing surfaces.
3. The bearing dimensions.
4. The viscosity of the lubricating oil.
Notice that item 2 returns to the phenomenon of tip speed. Surface velocity is simply the tip
speed of the inner bearing surface or shaft with respect to the outer bearing surface as illustrated
in the following diagram.
Figure 10, Bearing Loading
A hydrodynamic bearing is basically two infinite surfaces passing over one another with a velocity
equal to the surface velocity.
26
Catalog WSC/WDC-4
Bearing design, and consequently bearing life, is determined largely by the above criteria. Rpm,
by itself as an absolute, is only one half of the equation in the design process. One can also see
that higher rpm and smaller, lighter parts actually reduce the load and wear on bearings.
It is the surface velocity in conjunction with the load to be supported that determines bearing life
and therefore bearing selection. Referring to the analogy of the tractor trailer versus the utility
trailer, one sees that even though the utility trailer tires operate at a much higher rpm, the tractor
trailer wheel bearings must be much more massive due to the much heavier dynamic loading.
Shaft rotating speed has little effect on bearing wear.
The smaller rotating mass of a machine will improve the life of the bearing. Before the shaft
begins to spin, it rests on the bearing surface. Once the shaft starts rotating, an oil film develops
between the shaft and the bearing that supports the shaft. The low mass of a positive pressure
machine not only exerts a smaller static load on the bearings, but the fast spin-up enabled by the
low inertia of the modern gear drive compressor permits the supportive oil film to build up more
quickly.
Liquid refrigerant injection into compressor discharge-Unique
Although this sounds complex, this feature is quite simple. Most of the noise in all centrifugal
compressors results from high gas velocity in the discharge line.
The McQuay liquid injection system injects liquid refrigerant into the discharge gas through a
radial array of ports. This refrigerant mist absorbs sound energy (much like a foggy day) and the
flash gas cools the discharge gas leaving the compressor. The net result is significant noise
reduction.
In addition, by removing superheat from the discharge gas, the condenser becomes more efficient,
improving unit efficiency. Sound Levels -- One Of The Quietest Centrifugal Chillers In The
Industry.
McQuay centrifugal chillers are one of the quietest units available in the marketplace due to
several unique design features.
Quiet full load sound levels and QUIETER part load sound levels-Unique
The highest noise levels for McQuay chillers are at full load. As McQuay chillers unload, noise
levels reduce. Other chillers on the market are typically the opposite, with higher sound levels at
part load. Be certain to compare noise levels at several load conditions.
Moveable Discharge GeometryFigure 11, Movable Diffuser Geometry
The other feature to reduce
noise and increase stability at
Full Load
Stall or Surge at Part Load
Part Load
low loads is the McQuay
movable discharge geometry.
Less refrigerant is circulated as
the chiller capacity reduces.
The left drawing shows the
operation at full load of a unit
with a fixed compressor
discharge cross section. At full
load, a large quantity of gas is
discharged with a fairly uniform
Impeller
Impeller
Impeller
discharge velocity as indicated
by the arrows.
The middle drawing shows a fixed compressor discharge at reduced capacity. Note that the velocity is
not uniform and the refrigerant tends to reenter the impeller. This is caused by low velocity in the
discharge area and the high pressure in the condenser, resulting in unstable surge operation and with
noise and vibration generated.
Gas Flow at Discharge of
Impeller with Fixed Geometry
Catalog WSC/WDC-4
Gas Flow with
Movable Geometry
27
The right side drawing shows the unique McQuay movable discharge geometry. As the capacity
reduces, the movable unloader piston travels inward, reducing the discharge cross section area and
maintaining the refrigerant velocity. This mechanism allows capacity reduction to 10%.
Discharge Line Sound Packages
For extremely sensitive projects, an optional discharge line sound package is offered consisting of
sound insulation installed on the unit’s discharge line. An additional 2 to 4 dbA reduction normally
occurs.
ARI Standard 575 Sound Ratings
Sound data in accordance with ARI Standard 575 for individual units are available from your local
McQuay representative. Due to the large number of component combinations and variety of
applications, sound data is not included in this catalog.
Lubrication System
A separately driven electric oil pump assembly
supplies lubrication at controlled temperature and
pressure to all bearing surfaces and is the source
of hydraulic pressure for the capacity control
system.
The control system will not allow the compressor
to start until oil pressure, at the proper
temperature, is established. It also allows the oil
pump to operate after compressor shutdown to
provide lubrication during coast-down.
Lubricant from the pump is supplied to the
compressor through a water-cooled, brazed-plate
heat exchanger and single or dual five-micron oil
filters internal to the compressor. All bearing
surfaces are pressure lubricated. Drive gears
operate in a controlled lubricant mist atmosphere
that efficiently cools and lubricates them.
Lubricant is made available under pressure from
the compressor oil filter to the unit capacity
control system and is used to position the inlet
guide vanes in response to changes in leaving
chiller water temperature.
If a power failure occurs, an emergency oil reservoir provides adequate lubrication flow under
pressure, and prevents damage that could occur during the coast-down period with the oil pump
stopped.
Since the McQuay chillers are positive pressure, there is no need to change the lubricant or filter
on a regular basis. As with any equipment of this type, an annual oil check is recommended to
evaluate the lubricant condition.
Enhanced Surge Protection (Patent Pending)
ESP Minimizes Compressor Stall/Surge Damage
When centrifugal compressors operate at part load, the volume of refrigerant gas entering the
impeller is reduced. At the reduced flow, the impeller’s capacity to develop the peak load head is
also reduced. At conditions of low refrigerant flow and high compressor head (pressure
difference), stall and/or surge can occur (a stall is gas static in the impeller, a surge condition is
gas rapidly reversing direction through the impeller). A number of things can contribute to this
condition including inadequate maintenance of condenser tube cleanliness, a cooling tower or
control malfunction, unusual ambient temperatures, and others.
28
Catalog WSC/WDC-4
For these abnormal conditions, McQuay compressor designers have developed a protective
control system that senses the potential for a surge, looks at the entire chiller system operation and
takes corrective action if possible; or stops the compressor, to help prevent any damage from
occurring. This protection, called “ESP” is provided as standard on all McQuay centrifugal
compressors.
Refrigerant Comparison
The table at the right compares refrigerR-123
R-134a
Refrigerant
ants in common use today in centrifugal
6.10
124.1
Condenser Press. psig @ 100°F
compressors.
Evaporator Press. psig @ 40°F
(18.1)
35.0
Note that required compressor tip speeds (Inches of Mercury Vacuum)
Refrigerant. Circulated lbs/min./ton
3.08
3.00
are all within eight percent of each other.
Gas Flow cfm/ton
18.15
3.17
656
682
All McQuay centrifugal chillers use Tip Speed ft./sec.
0.02
0.00
refrigerant R-134a. The machine design Ozone Depletion Potential (ODP)
characteristics of this refrigerant (and its predecessor, R-12) such as small moving parts, low
mass, low inertia, quick spin-up and coast-down, and simplicity of design, have continuously
proven themselves since the first chiller was introduced in 1962. The small and lightweight
rotating parts lend themselves to easy servicing of the compressor and its associated parts and
piping.
Environmentally and Operator Safe - The Real Facts
As the air conditioning industry prepares for the future, R-134a stands out as the logical choice
when using a balanced approach. The "balanced approach" takes into account the following facts
on environmental concerns:
•
Ozone Depletion Potential (ODP); measures the impact of a substance on the depletion of the
ozone layer in the upper atmosphere. With refrigerants, this action is caused by chlorine, the
first “C” in HCFC (R)-123. R-134a contains no chlorine and has a zero ODP and zero
negative effect on the ozone layer.
•
Global Warming Potential (GWP); measures the contribution of a substance to the greenhouse
gas effect which causes global warming. This is a pound-to-pound comparison, discounting
the application of the substance and any other effects caused by its use. The numbers, relative
to CO2 for a 100 year integration time horizon are, R-123=90, R-134a=1300, R-22=1500.
Manufacturers utilizing R-123 would have you believe that GWP is the primary and important
measurement of global warming potential of a refrigerant. This is untrue as is explained in the
following description of Total Equivalent Warming Potential.
•
Total Equivalent Warming Impact (TEWI); is a combination of the refrigerant GWP, unit
refrigerant emissions rate, and the refrigeration system’s energy efficiency. Science has
agreed that a systems approach is necessary to evaluate the
real effect of a substance on global warming. This is TEWI.
In a chiller, the contribution of the GWP is insignificant when
compared to the effect of a unit’s power needs translated to
power plant CO2 emissions.
There is no meaningful
difference between the TEWI of R-134a, R-22 or R-123. The
percentages shown on the right will vary slightly depending
on unit refrigerant loss and on the efficiency of local power
generation. Bottom line, equipment operators should keep
equipment leak free and operate as efficiently as possible.
Since annualized energy consumption (think power plant
output) is a basis for measurement, McQuay’s superior part
load efficiencies result in lower overall power plant CO2
emissions and can actually deliver a lower TEWI than
competition.
Catalog WSC/WDC-4
29
•
True System Efficiency (KW/ton or COP); deals with the total annual power consumption of a
chiller system including auxiliaries such as pumps, purge units, Pre-Vac heaters and fans-of
great importance in determining facility energy cost and power plant CO2 emissions.
•
Toxicity and Flammability Rating; per 1997 ASHRAE Fundamentals Handbook
•
R-134a Ÿ A-1
R-123 Ÿ B-1
Where A=Toxicity not identified
B=Evidence of toxicity identified
1=No flame propagation in air at 65°F, 50% rh and one atmosphere pressure
A certain future for R-134a:
The Clean Air Act of November 1990 allows the EPA to accelerate the phase-out schedule of
Class I (CFC) and Class II (HCFC) refrigerants if it deems it necessary. This leaves the future
of HCFCs (which includes R-22 and R-123) uncertain. R-134a will not be regulated or
phased out by the Clean Air Act or the Montreal Protocol. The commercial air conditioning,
home appliance, and automotive industries are just a few of the many markets that are using
R-134a now and for years into the future. This large market demand for R-134a translates to a
readily available and competitively priced product.
Compact Design
Small Footprint Cuts Installation Costs
At comparable cooling capacities, R-134a requires less than 3.2 cfm (1.5 l/sec) per ton of
refrigeration to be circulated by the compressor. R-123 requires over 18.0 cfm (8.5 l/sec) per ton.
The substantial increase in refrigerant volume requires significantly larger suction piping and
compressor components in negative pressure designs to maintain reasonable gas velocity, noise
levels and refrigerant pressure losses. Conversely, the small physical size of McQuay centrifugal
chillers will:
• Permit design of smaller equipment rooms.
•
Cost less to rig and install.
•
Lower joint surface area for lower likelihood of leaks.
•
In smaller capacities, allow transit through standard equipment room doors, permitting
building construction to proceed on schedule before receipt of the chiller equipment.
Heat Exchangers
McQuay packaged centrifugal chillers are equipped with new high performance heat exchangers.
The unique design greatly increases heat transfer and reduces unit footprint and refrigerant charge
compared to previous designs. In many cases vessel length has been reduced by 40 percent.
Chillers are designed, constructed and tested in accordance with ASME Section VIII, ASHRAE
Standard 15 requirements and TEMA recommendations.
The replaceable water tubes are internally rifled and externally enhanced copper and are
mechanically bonded to steel tube sheets. Standard tubes are 0.025-inch wall thickness. Optional
tubes include 0.028 inch and 0.035-inch wall thickness on either vessels and 90/10 cupro-nickel,
304 stainless steel or titanium material. Clad tube sheets and epoxy-coated heads can be provided.
Vessels are available for 1, 2 or 3-pass water flow. A ¾-inch or 1½-inch thick, flexible foam
evaporator insulation is a factory installed optional. With either of these options, all seams are
glued to form an effective vapor barrier and the entire chiller barrel, including non-connection
heads and tube sheets, are insulated. Detailed information on the insulation can be found in the
“Physical Data” section of this catalog.
30
Catalog WSC/WDC-4
Retrofit Disassembly
It is estimated that fifty percent of retrofit applications require partial or complete disassembly of
the chiller. On WSC chillers, McQuay offers two solutions to this problem to best fit job
conditions.
On-site disassembly-The major components; evaporator, condenser, and compressor, are shipped
fully assembled and can be taken apart at the site to facilitate difficult rigging work. The chillers
are shipped assembled from the factory after testing, and then disassembled and reassembled on
site under supervision of authorized McQuay service personnel. Individual component weights
are shown in the Physical Data section of this catalog.
Shipped disassembled-Chillers can be shipped knocked down from the factory. The evaporator,
condenser and oil pump are shipped bolted together and easily unbolted at the job site into the
pieces shown below. Other options, such as shipping less compressor or less compressor and
control panel are also available.
COMPRESSOR
STARTER
OIL PUMP
UNIT
CONTROLLER
EVAPORATOR
SUPPORT
CONDENSER
Catalog WSC/WDC-4
31
TYPE I ... McQuay provides ease of installation without requiring construction alterations of
entryways to your building. The compressor and compressor control box are removed and put on
a skid. All associated wiring and piping will remain attached if possible. The remaining loose
parts will be packaged in a separate crate.
A.
B.
C.
D.
E.
F.
G.
H.
I.
J.
K.
Blockoffs will cover all openings on the compressor and vessels.
The compressor and vessels will receive a nitrogen holding charge.
The compressor will not be insulated at the factory. An insulation kit will be shipped with the unit.
The starter will ship loose. Bracket and cable kit to be included for unit-mounted starters and/or
cableway for mini-cabinet.
The evaporator will be insulated at the factory.
Refrigerant will not be shipped with the unit and must secured locally and furnished and installed by
the installer.
Oil will be shipped in containers from the factory for field installation.
All field-piping connections will be victaulic, o-ring face seal or copper brazing.
All free piping ends will be capped.
Touch-up paint will be included.
The unit will undergo the rigorous, full McQuay test program at the factory.
TYPE II ... For those really tight installations, McQuay provides a total knockdown of the unit,
allowing entry to the chiller site using already existing entryways. Compressor and terminal box
are removed and put on a skid. The condenser, evaporator, and oil pump and supports will remain
connected only by the attachment bolts for easy disassembly at the job site or riggers. All wiring
and piping that interconnects the components will be removed. The remaining loose parts will be
packaged in a separate crate.
A. Blockoffs will cover all openings on the compressor and vessels.
B. The compressor and vessels will receive a nitrogen holding charge.
C. The compressor will not be insulated at the factory. An insulation kit will be shipped with the
unit.
D. Only the evaporator shell will be factory insulated. Loose insulation will be shipped for the
remaining surface areas.
E. The starter will ship loose. Bracket and cable kit to be included for all unit-mounted starters
and/or cableway for mini-cabinet.
F. Refrigerant will be field supplied.
G. All field piping connections will be victaulic, o-ring face seal or copper brazing.
H. All free piping ends will be capped.
I. Touch-up paint will be included.
J. A bolted bracket instead of a weld will mount the oil pump.
K. The discharge piping assembly will have a bolted flange connection at the condenser. This
assembly will be shipped loose.
L. Piping that is attached to a component will be supported if it is not rigid.
M. All pressure vessels receive the full ASME testing. The compressor and oil pump are pressure
checked and run tested. The chiller will require field leak testing after assembly at its final
location.
32
Catalog WSC/WDC-4
Table 2, Type I Knockdown Dimensions & Weights
UNIT
SIZE
VESSEL
CODE
UNIT
WIDTH
UNIT
HEIGHT
COMPRESSOR
WIDTH
HEIGHT
COMPRESSOR
WEIGHT
050
E1809 / C1609
44.1 (1118.9)
64.6 (1640.3)
20.0 (508.0)
20.8 (528.6)
050
E2009 / C1609
44.1 (1118.9)
64.6 (1640.3)
20.0 (508.0)
20.8 (528.6)
050
E2009 / C1809
44.1 (1118.9)
64.6 (1640.3)
20.0 (508.0)
20.8 (528.6)
050
E2209 / C2009
44.4 (1128.3)
64.6 (1640.3)
20.0 (508.0)
20.8 (528.6)
050
E1812 / C1612
44.1 (1118.9)
64.6 (1640.3)
20.0 (508.0)
20.8 (528.6)
050
E2012 / C1612
44.1 (1118.9)
64.6 (1640.3)
20.0 (508.0)
20.8 (528.6)
050
E2012 / C1812
44.1 (1118.9)
64.6 (1640.3)
20.0 (508.0)
20.8 (528.6)
050
E2212 / C2012
44.4 (1128.3)
64.6 (1640.3)
20.0 (508.0)
20.8 (528.6)
063
E2009 / C1809
57.1 (1450.6)
61.6 (1564.4)
44.0 (1118.6)
25.1 (638.3)
063
E2209 / C2009
57.1 (1450.6)
64.0 (1624.8)
44.0 (1118.6)
25.1 (638.3)
063
E2209 / C2209
57.1 (1450.6)
64.0 (1624.8)
44.0 (1118.6)
25.1 (638.3)
063
E2609 / C2209
57.1 (1450.6)
67.5 (1715.0)
44.0 (1118.6)
25.1 (638.3)
063
E2609 / C2609
57.1 (1450.6)
73.1 (1857.8)
44.0 (1118.6)
25.1 (638.3)
063
E3009 / C2609
56.8 (1441.7)
75.7 (1922.0)
44.0 (1118.6)
25.1 (638.3)
063
E2012 / C1812
57.1 (1450.6)
61.6 (1564.4)
44.0 (1118.6)
25.1 (638.3)
063
E2212 / C2012
57.1 (1450.6)
64.0 (1624.8)
44.0 (1118.6)
25.1 (638.3)
063
E2212 / C2212
57.1 (1450.6)
64.0 (1624.8)
44.0 (1118.6)
25.1 (638.3)
063
E2612 / C2212
57.1 (1450.6)
67.5 (1715.0)
44.0 (1118.6)
25.1 (638.3)
063
E2612 / C2612
57.1 (1450.6)
73.1 (1857.8)
44.0 (1118.6)
25.1 (638.3)
063
E3012 / C2612
56.8 (1441.7)
75.7 (1922.0)
44.0 (1118.6)
25.1 (638.3)
079
E2209 / C2209
50.2 (1274.6)
62.3 (1581.7)
43.6 (1108.2)
25.1 (638.3)
079
E2609 / C2209
52.7 (1338.3)
63.9 (1622.8)
43.6 (1108.2)
25.1 (638.3)
079
E2609 / C2609
52.7 (1338.3)
69.5 (1765.6)
43.6 (1108.2)
25.1 (638.3)
079
E3009 / C2609
57.1 (1449.8)
74.0 (1878.6)
43.6 (1108.2)
25.1 (638.3)
079
E3009 / C3009
59.0 (1499.4)
79.4 (2016.8)
43.6 (1108.2)
25.1 (638.3)
079
E3609 / C3009
74.7 (1896.1)
78.8 (2001.0)
43.6 (1108.2)
25.1 (638.3)
079
E2212 / C2212
50.2 (1274.6)
62.3 (1581.7)
43.6 (1108.2)
25.1 (638.3)
079
E2612 / C2212
52.7 (1338.3)
63.9 (1622.8)
43.6 (1108.2)
25.1 (638.3)
079
E2612 / C2612
52.7 (1338.3)
69.5 (1765.6)
43.6 (1108.2)
25.1 (638.3)
079
E3012 / C2612
57.1 (1449.8)
74.0 (1878.6)
43.6 (1108.2)
25.1 (638.3)
079
E3012 / C3012
59.0 (1499.4)
79.4 (2016.8)
43.6 (1108.2)
25.1 (638.3)
079
E3612 / C3012
74.7 (1896.1)
78.8 (2001.0)
43.6 (1108.2)
25.1 (638.3)
087
E2609 / C2209
52.7 (1338.3)
65.2 (1656.3)
43.6 (1108.2)
25.1 (638.3)
087
E2609 / C2609
52.7 (1338.3)
70.8 (1799.1)
43.6 (1108.2)
25.1 (638.3)
087
E3009 / C2609
57.1 (1449.8)
68.8 (1746.5)
43.6 (1108.2)
25.1 (638.3)
087
E3009 / C3009
59.5 (1510.5)
78.7 (1998.0)
43.6 (1108.2)
25.1 (638.3)
087
E3609 / C3009
74.7 (1896.1)
78.8 (2001.0)
43.6 (1108.2)
25.1 (638.3)
087
E2612 / C2212
52.7 (1338.3)
65.2 (1656.3)
43.6 (1108.2)
25.1 (638.3)
087
E2612 / C2612
52.7 (1338.3)
70.8 (1799.1)
43.6 (1108.2)
25.1 (638.3)
087
E3012 / C2612
57.1 (1449.8)
68.8 (1746.5)
43.6 (1108.2)
25.1 (638.3)
087
E3012 / C3012
59.5 (1510.5)
78.7 (1998.0)
43.6 (1108.2)
25.1 (638.3)
087
E3612 / C3012
74.7 (1896.1)
78.8 (2001.0)
43.6 (1108.2)
25.1 (638.3)
087
E3612 / C3612
80.7 (2049.3)
89.2 (2264.4)
43.6 (1108.2)
25.1 (638.3)
100
E3012 / C3012
67.4 (1712.2)
76.5 (1943.1)
44.0 (1117.9)
31.5 (800.1)
100
E3612 / C3012
77.2 (1961.6)
77.6 (1971.5)
44.0 (1117.9)
31.5 (800.1)
100
E3612 / C3612
83.2 (2114.0)
77.6 (1971.5)
44.0 (1117.9)
31.5 (800.1)
100
E4212 / C3612
86.2 (2190.5)
76.4 (1940.8)
44.0 (1117.9)
31.5 (800.1)
100
E4212 / C4212
92.2 (2342.9)
86.7 (2202.7)
44.0 (1117.9)
31.5 (800.1)
100
E4812 / C4212
98.2 (2495.3)
90.6 (2300.2)
44.0 (1117.9)
31.5 (800.1)
113
E3012 / C3012
67.4 (1712.2)
76.5 (1943.1)
44.0 (1117.9)
31.5 (800.1)
113
E3612 / C3012
77.2 (1961.6)
77.6 (1971.5)
44.0 (1117.9)
31.5 (800.1)
113
E3612 / C3612
83.2 (2114.0)
77.6 (1971.5)
44.0 (1117.9)
31.5 (800.1)
113
E4212 / C3612
86.2 (2190.5)
76.4 (1940.8)
44.0 (1117.9)
31.5 (800.1)
113
E4212 / C4212
92.2 (2342.9)
86.7 (2202.7)
44.0 (1117.9)
31.5 (800.1)
113
E4812 / C4212
98.2 (2495.3)
90.6 (2300.2)
44.0 (1117.9)
31.5 (800.1)
113
E4812 / C4812
104.2 (2647.7)
90.6 (2300.2)
44.0 (1117.9)
31.5 (800.1)
126
E3612 / C3012
77.2 (1961.6)
77.6 (1971.5)
44.0 (1117.9)
31.5 (800.1)
126
E3612 / C3612
83.2 (2114.0)
77.6 (1971.5)
44.0 (1117.9)
31.5 (800.1)
126
E4212 / C3612
86.2 (2190.5)
76.4 (1940.8)
44.0 (1117.9)
31.5 (800.1)
126
E4212 / C4212
92.2 (2342.9)
86.7 (2202.7)
44.0 (1117.9)
31.5 (800.1)
126
E4812 / C4212
98.2 (2495.3)
90.6 (2300.2)
44.0 (1117.9)
31.5 (800.1)
126
E4812 / C4812
104.2 (2647.7)
90.6 (2300.2)
44.0 (1117.9)
31.5 (800.1)
Notes:
1. The overall vessel length can vary depending on the specified tube length and pass arrangement.
drawings, or unit dimensions beginning on page 66 in this catalog for specific vessel lengths.
2. Allow plus / minus 1 inch (24.5mm) for factory manufacturing tolerance.
3. All dimensions are shown in inches (mm).
4. All weights are shown in lbs (kg).
Catalog WSC/WDC-4
1589 (718)
1589 (718)
1835 (831)
2230 (1010)
1870 (847)
1870 (847)
2183 (989)
2677 (1213)
1835 (831)
2230 (1010)
2511 (1137)
2511 (1137)
3210 (1454)
3210 (1454)
2183 (989)
2677 (1213)
3031 (1373)
3031 (1373)
3900 (1767)
3900 (1767)
2511 (1137)
2511 (1137)
3210 (1454)
3210 (1454)
4356 (1973)
4356 (1973)
3031 (1373)
3031 (1373)
3900 (1767)
3900 (1767)
5333 (2416)
5333 (2416)
2511 (1137)
3210 (1454)
3210 (1454)
4356 (1973)
4356 (1973)
3031 (1373)
3900 (1767)
3900 (1767)
5333 (2416)
5333 (2416)
7508 (3401)
5333 (2416)
5333 (2416)
7508 (3401)
7508 (3401)
10267 (4651)
10267 (4651)
5333 (2416)
5333 (2416)
7508 (3401)
7508 (3401)
10267 (4651)
10267 (4651)
13077 (5924)
5333 (2416)
7508 (3401)
7508 (3401)
10267 (4651)
10267 (4651)
13077 (5924)
SHIPPING
WEIGHT wo/
COMPRESSOR
6102 (2772)
6460 (2936)
6725 (3055)
7368 (3347)
6834 (3105)
7263 (3299)
7597 (3451)
8407 (3818)
6412 (2960)
7119 (3281)
7416 (3415)
8248 (3793)
8984 (4127)
10892 (4992)
7284 (3356)
8182 (3763)
8557 (3933)
9577 (4396)
10494 (4803)
11903 (5451)
8140 (3704)
8980 (4085)
9716 (4419)
10892 (4952)
12076 (5489)
13913 (6322)
9281 (4221)
10309 (4688)
11226 (5104)
12635 (5743)
14119 (6416)
16339 (7423)
8980 (4085)
9716 (4419)
10892 (4952)
12076 (5489)
13913 (6322)
10309 (4688)
11226 (5104)
12635 (5743)
14118 (6415)
16339 (7423)
18584 (8441)
14597 (6643)
16778 (7632)
19026 (8652)
21657 (10845)
24498 (11134)
27224 (12370)
14597 (6643)
16778 (7632)
19026 (8652)
21657 (10845)
24498 (11134)
27224 (12370)
30216 (13727)
16880 (7678)
19128 (8698)
21657 (9845)
24498 (11134)
27224 (12370)
30216 (13727)
Consult the McQuay certified submittal
33
Table 3, Type II Knockdown Dimensions & Weights
UNIT
SIZE
VESSEL
CODE
CONDENSER
HEIGHT
35.3 (895.6)
35.3 (895.6)
35.3 (895.6)
37.4 (948.9)
35.3 (895.6)
35.3 (895.6)
35.3 (895.6)
37.4 (948.9)
36.8 (933.5)
36.8 (933.5)
36.8 (933.5)
36.8 (933.5)
42.3 (1073.2)
42.3 (1073.2)
36.8 (933.5)
36.8 (933.5)
36.8 (933.5)
36.8 (933.5)
42.3 (1073.2)
42.3 (1073.2)
33.1 (841.0)
35.9 (911.4)
39.3 (997.0)
39.3 (997.0)
45.8 (1162.1)
45.8 (1162.1)
33.1 (841.0)
35.9 (911.4)
39.3 (997.0)
39.3 (997.0)
45.8 (1162.1)
45.8 (1162.1)
36.8 (933.5)
41.8 (1060.5)
41.8 (1060.5)
45.8 (1162.1)
45.8 (1162.1)
36.8 (933.5)
41.8 (1060.5)
41.8 (1060.5)
45.8 (1162.1)
45.8 (1162.1)
51.8 (1314.5)
46.2 (1172.7)
46.2 (1172.7)
52.1 (1322.3)
52.1 (1322.3)
57.6 (1462.0)
57.6 (1462.0)
46.2 (1172.7)
46.2 (1172.7)
52.1 (1322.3)
52.1 (1322.3)
57.6 (1462.0)
57.6 (1462.0)
63.5 (1612.9)
46.2 (1172.7)
52.1 (1322.3)
52.1 (1322.3)
57.6 (1462.0)
57.6 (1462.0)
63.5 (1612.9)
EVAPORATOR
WIDTH
33.3 (844.6)
33.3 (844.6)
33.3 (844.6)
34.6 (879.1)
33.3 (844.6)
33.3 (844.6)
33.3 (844.6)
34.6 (879.1)
34.6 (877.8)
34.6 (877.8)
34.6 (877.8)
39.2 (996.7)
39.2 (996.7)
42.6 (1081.0)
34.6 (877.8)
34.6 (877.8)
34.6 (877.8)
39.2 (996.7)
39.2 (996.7)
42.6 (1081.0)
32.8 (834.1)
36.7 (933.2)
36.7 (933.2)
40.1 (1017.8)
42.6 (1081.0)
48.1 (1222.2)
32.8 (834.1)
36.7 (933.2)
36.7 (933.2)
40.1 (1017.8)
42.6 (1081.0)
48.1 (1222.2)
39.2 (996.7)
39.2 (996.7)
42.6 (1081.3)
42.6 (1081.3)
48.1 (1222.2)
39.2 (996.7)
39.2 (996.7)
42.6 (1081.3)
42.6 (1081.3)
48.1 (1222.2)
48.1 (1222.2)
48.4 (1229.6)
52.1 (1324.1)
52.1 (1324.1)
54.4 (1382.5)
54.4 (1382.5)
60.1 (1527.0)
48.4 (1229.6)
52.1 (1324.1)
52.1 (1324.1)
54.4 (1382.5)
54.4 (1382.5)
60.1 (1527.0)
60.1 (1527.0)
52.1 (1324.1)
52.1 (1324.1)
54.4 (1382.5)
54.4 (1382.5)
60.1 (1527.0)
60.1 (1527.0)
HEIGHT
28.8 (731.3)
28.8 (731.3)
28.8 (731.3)
30.2 (767.1)
28.8 (731.3)
28.8 (731.3)
28.8 (731.3)
30.2 (767.1)
28.8 (731.3)
35.4 (899.9)
35.4 (899.9)
35.9 (912.6)
35.9 (912.6)
37.3 (948.4)
28.8 (731.3)
35.4 (899.9)
35.4 (899.9)
35.9 (912.6)
35.9 (912.6)
37.3 (948.4)
31.5 (799.8)
33.2 (842.3)
33.2 (842.3)
37.3 (948.4)
37.3 (948.4)
43.7 (1109.7)
31.5 (799.8)
33.2 (842.3)
33.2 (842.3)
37.3 (948.4)
37.3 (948.4)
43.7 (1109.7)
35.9 (912.6)
35.9 (912.6)
37.3 (948.4)
37.3 (948.4)
43.7 (1109.7)
35.9 (912.6)
35.9 (912.6)
37.3 (948.4)
37.3 (948.4)
43.7 (1109.7)
43.7 (1109.7)
38.4 (974.6)
44.1 (1120.6)
44.1 (1120.6)
51.5 (1307.6)
51.5 (1307.6)
57.1 (1449.6)
38.4 (974.6)
44.1 (1120.6)
44.1 (1120.6)
51.5 (1307.6)
51.5 (1307.6)
57.1 (1449.6)
57.1 (1449.6)
44.1 (1120.6)
44.1 (1120.6)
51.5 (1307.6)
51.5 (1307.6)
57.1 (1449.6)
57.1 (1449.6)
COMPRESSOR
HEIGHT
050 E1809 / C1609
20.8 (528.6)
050 E2009 / C1609
20.8 (528.6)
050 E2009 / C1809
20.8 (528.6)
050 E2209 / C2009
20.8 (528.6)
050 E1812 / C1612
20.8 (528.6)
050 E2012 / C1612
20.8 (528.6)
050 E2012 / C1812
20.8 (528.6)
050 E2212 / C2012
20.8 (528.6)
063 E2009 / C1809
25.1 (638.3)
063 E2209 / C2009
25.1 (638.3)
063 E2209 / C2209
25.1 (638.3)
063 E2609 / C2209
25.1 (638.3)
063 E2609 / C2609
25.1 (638.3)
063 E3009 / C2609
25.1 (638.3)
063 E2012 / C1812
25.1 (638.3)
063 E2212 / C2012
25.1 (638.3)
063 E2212 / C2212
25.1 (638.3)
063 E2612 / C2212
25.1 (638.3)
063 E2612 / C2612
25.1 (638.3)
063 E3012 / C2612
25.1 (638.3)
079 E2209 / C2209
25.1 (638.3)
079 E2609 / C2209
25.1 (638.3)
079 E2609 / C2609
25.1 (638.3)
079 E3009 / C2609
25.1 (638.3)
079 E3009 / C3009
25.1 (638.3)
079 E3609 / C3009
25.1 (638.3)
079 E2212 / C2212
25.1 (638.3)
079 E2612 / C2212
25.1 (638.3)
079 E2612 / C2612
25.1 (638.3)
079 E3012 / C2612
25.1 (638.3)
079 E3012 / C3012
25.1 (638.3)
079 E3612 / C3012
25.1 (638.3)
087 E2609 / C2209
25.1 (638.3)
087 E2609 / C2609
25.1 (638.3)
087 E3009 / C2609
25.1 (638.3)
087 E3009 / C3009
25.1 (638.3)
087 E3609 / C3009
25.1 (638.3)
087 E2612 / C2212
25.1 (638.3)
087 E2612 / C2612
25.1 (638.3)
087 E3012 / C2612
25.1 (638.3)
087 E3012 / C3012
25.1 (638.3)
087 E3612 / C3012
25.1 (638.3)
087 E3612 / C3612
25.1 (638.3)
100 E3012 / C3012
31.5 (800.1)
100 E3612 / C3012
31.5 (800.1)
100 E3612 / C3612
31.5 (800.1)
100 E4212 / C3612
31.5 (800.1)
100 E4212 / C4212
31.5 (800.1)
100 E4812 / C4212
31.5 (800.1)
113 E3012 / C3012
31.5 (800.1)
113 E3612 / C3012
31.5 (800.1)
113 E3612 / C3612
31.5 (800.1)
113 E4212 / C3612
31.5 (800.1)
113 E4212 / C4212
31.5 (800.1)
113 E4812 / C4212
31.5 (800.1)
113 E4812 / C4812
31.5 (800.1)
126 E3612 / C3012
31.5 (800.1)
126 E3612 / C3612
31.5 (800.1)
126 E4212 / C3612
31.5 (800.1)
126 E4212 / C4212
31.5 (800.1)
126 E4812 / C4212
31.5 (800.1)
126 E4812 / C4812
31.5 (800.1)
Notes:
1.
The overall vessel length can vary depending on the specified tube length and pass arrangement. Consult the McQuay certified submittal
drawings, or unit dimensions beginning on page 66 in this catalog for specific vessel lengths.
2.
Allow plus / minus 1 inch (24.5mm) for manufacturing tolerance.
3.
All dimensions are shown in inches (mm).
4.
All weights are shown in lbs (kg).
34
WIDTH
28.8 (730.8)
28.8 (730.8)
28.8 (730.8)
33.8 (857.3)
28.8 (730.8)
28.8 (730.8)
28.8 (730.8)
33.8 (857.3)
31.8 (806.5)
30.5 (774.2)
30.5 (774.2)
30.5 (774.2)
36.0 (914.9)
36.0 (914.9)
31.8 (806.5)
30.5 (774.2)
30.5 (774.2)
30.5 (774.2)
36.0 (914.9)
36.0 (914.9)
30.5 (775.2)
30.5 (775.2)
30.5 (775.2)
36.0 (914.9)
41.4 (1052.3)
41.9 (1063.5)
30.5 (775.2)
30.5 (775.2)
30.5 (775.2)
36.0 (914.9)
41.4 (1052.3)
41.9 (1063.5)
30.5 (775.2)
36.0 (914.9)
36.0 (914.9)
41.9 (1063.5)
41.9 (1063.5)
30.5 (775.2)
36.0 (914.9)
36.0 (914.9)
41.9 (1063.5)
41.9 (1063.5)
46.2 (1173.2)
41.0 (1041.9)
41.0 (1041.9)
45.3 (1151.4)
45.3 (1151.4)
49.6 (1260.1)
49.6 (1260.1)
41.0 (1041.9)
41.0 (1041.9)
45.3 (1151.4)
45.3 (1151.4)
49.6 (1260.1)
49.6 (1260.1)
53.9 (1369.1)
41.0 (1041.9)
45.3 (1151.4)
45.3 (1151.4)
49.6 (1260.1)
49.6 (1260.1)
53.9 (1369.1)
FRT & BACK
SUPPORT
WIDTH
HEIGHT
8.0 (203.2) 25.9 (657.1)
8.0 (203.2) 25.9 (657.1)
8.0 (203.2) 25.9 (657.1)
8.0 (203.2) 25.9 (657.1)
8.0 (203.2) 25.9 (657.1)
8.0 (203.2) 25.9 (657.1)
8.0 (203.2) 25.9 (657.1)
8.0 (203.2) 25.9 (657.1)
8.0 (203.2) 22.9 (580.9)
8.0 (203.2) 22.9 (580.9)
8.0 (203.2) 22.1 (561.8)
8.0 (203.2) 22.1 (561.8)
8.0 (203.2) 27.7 (704.6)
8.0 (203.2) 27.0 (685.5)
8.0 (203.2) 22.9 (580.9)
8.0 (203.2) 22.9 (580.9)
8.0 (203.2) 22.1 (561.8)
8.0 (203.2) 22.1 (561.8)
8.0 (203.2) 27.7 (704.6)
8.0 (203.2) 27.0 (685.5)
8.0 (203.2) 20.6 (522.0)
8.0 (203.2) 20.6 (522.0)
8.0 (203.2) 26.2 (665.0)
8.0 (203.2) 25.4 (645.2)
8.0 (203.2) 30.9 (783.8)
8.0 (203.2) 25.5 (648.7)
8.0 (203.2) 20.6 (522.0)
8.0 (203.2) 20.6 (522.0)
8.0 (203.2) 26.2 (665.0)
8.0 (203.2) 25.4 (645.2)
8.0 (203.2) 30.9 (783.8)
8.0 (203.2) 25.5 (648.7)
8.0 (203.2) 20.6 (522.0)
8.0 (203.2) 26.2 (665.0)
8.0 (203.2) 25.4 (645.2)
8.0 (203.2) 30.9 (783.8)
8.0 (203.2) 25.5 (648.7)
8.0 (203.2) 20.6 (522.0)
8.0 (203.2) 26.2 (665.0)
8.0 (203.2) 25.4 (645.2)
8.0 (203.2) 30.9 (783.8)
8.0 (203.2) 25.5 (648.7)
8.0 (203.2) 35.9 (912.1)
8.0 (203.2) 28.6 (725.4)
8.0 (203.2) 24.4 (619.5)
8.0 (203.2) 24.4 (619.5)
8.0 (203.2) 18.6 (473.5)
8.0 (203.2) 21.4 (543.3)
8.0 (203.2) 19.6 (498.9)
8.0 (203.2) 28.6 (725.4)
8.0 (203.2) 24.4 (619.5)
8.0 (203.2) 24.4 (619.5)
8.0 (203.2) 18.6 (473.5)
8.0 (203.2) 21.4 (543.3)
8.0 (203.2) 19.6 (498.9)
8.0 (203.2) 19.6 (498.9)
8.0 (203.2) 24.4 (619.5)
8.0 (203.2) 24.4 (619.5)
8.0 (203.2) 18.6 (473.5)
8.0 (203.2) 21.4 (543.3)
8.0 (203.2) 19.6 (498.9)
8.0 (203.2) 19.6 (498.9)
WIDTH
20.0 (508.0)
20.0 (508.0)
20.0 (508.0)
20.0 (508.0)
20.0 (508.0)
20.0 (508.0)
20.0 (508.0)
20.0 (508.0)
44.0 (1118.6)
44.0 (1118.6)
44.0 (1118.6)
44.0 (1118.6)
44.0 (1118.6)
44.0 (1118.6)
44.0 (1118.6)
44.0 (1118.6)
44.0 (1118.6)
44.0 (1118.6)
44.0 (1118.6)
44.0 (1118.6)
43.6 (1108.2)
43.6 (1108.2)
43.6 (1108.2)
43.6 (1108.2)
43.6 (1108.2)
43.6 (1108.2)
43.6 (1108.2)
43.6 (1108.2)
43.6 (1108.2)
43.6 (1108.2)
43.6 (1108.2)
43.6 (1108.2)
43.6 (1108.2)
43.6 (1108.2)
43.6 (1108.2)
43.6 (1108.2)
43.6 (1108.2)
43.6 (1108.2)
43.6 (1108.2)
43.6 (1108.2)
43.6 (1108.2)
43.6 (1108.2)
43.6 (1108.2)
44.0 (1117.9)
44.0 (1117.9)
44.0 (1117.9)
44.0 (1117.9)
44.0 (1117.9)
44.0 (1117.9)
44.0 (1117.9)
44.0 (1117.9)
44.0 (1117.9)
44.0 (1117.9)
44.0 (1117.9)
44.0 (1117.9)
44.0 (1117.9)
44.0 (1117.9)
44.0 (1117.9)
44.0 (1117.9)
44.0 (1117.9)
44.0 (1117.9)
44.0 (1117.9)
Catalog WSC/WDC-4
Type II Table Continued
UNIT
SIZE
OIL PUMP
VESSEL CODE
WIDTH
HEIGHT
CONDENSER
WEIGHT
EVAPORATOR
WEIGHT
COMPRESSOR
WEIGHT
UNIT
SHIPPING
WEIGHT
6972 (3162)
7330 (3326)
7595 (3445)
8238 (3737)
7704 (3495)
8133 (3689)
8467 (3841)
9277 (4208)
9612 (4360)
10319 (4681)
10616 (4815)
11448 (5193)
12184 (5527)
14092 (6392)
10484 (4756)
11382 (5163)
11757 (5333)
12777 (5796)
13694 (6203)
15103 (6851)
11340 (5144)
12180 (5525)
12916 (5859)
14092 (6392)
15276 (6929)
17113 (7762)
12481 (5661)
13509 (6128)
14426 (6544)
15835 (7183)
17319 (7856)
19539 (8863)
12180 (5525)
12916 (5859)
14092 (6392)
15276 (6929)
17113 (7762)
13509 (6128)
14426 (6544)
15835 (7183)
17318 (7855)
19539 (8863)
21784 (9881)
20597 (9343)
22778 (10332)
25026 (11352)
27657 (13545)
30498 (13834)
33224 (15070)
20597 (9343)
22778 (10332)
25026 (11352)
27657 (13545)
30498 (13834)
33224 (15070)
36216 (16427)
22880 (10378)
25128 (11398)
27657 (12545)
30498 (13834)
33224 (15070)
36216 (16427)
050
1589 (718)
E1809 / C1609
n/a
n/a
2237 (1013)
870 (390)
050
1589 (718)
E2009 / C1609
n/a
n/a
2543 (1152)
870 (390)
050
1835 (831)
E2009 / C1809
n/a
n/a
2543 (1152)
870 (390)
050
2230 (1010)
E2209 / C2009
n/a
n/a
2708 (1227)
870 (390)
050
1870 (847)
E1812 / C1612
n/a
n/a
2504 (1134)
870 (390)
050
1870 (847)
E2012 / C1612
n/a
n/a
2862 (1296)
870 (390)
050
2183 (989)
E2012 / C1812
n/a
n/a
2862 (1296)
870 (390)
050
2677 (1213)
E2212 / C2012
n/a
n/a
3071 (1391)
870 (390)
063
1835 (831)
E2009 / C1809
20.8 (528.1) 30.6 (778.0)
2543 (1152)
3200 (1440)
063
2230 (1010)
E2209 / C2009
20.8 (528.1) 30.6 (778.0)
2708 (1227)
3200 (1440)
063
2511 (1137)
E2209 / C2209
20.8 (528.1) 30.6 (778.0)
2708 (1227)
3200 (1440)
063
2511 (1137)
E2609 / C2209
20.8 (528.1) 30.6 (778.0)
3381 (1532)
3200 (1440)
063
3210 (1454)
E2609 / C2609
20.8 (528.1) 30.6 (778.0)
3381 (1532)
3200 (1440)
063
3210 (1454)
E3009 / C2609
20.8 (528.1) 30.6 (778.0)
4397 (1992)
3200 (1440)
063
2183 (989)
E2012 / C1812
20.8 (528.1) 30.6 (778.0)
2862 (1296)
3200 (1440)
063
2677 (1213)
E2212 / C2012
20.8 (528.1) 30.6 (778.0)
3071 (1391)
3200 (1440)
063
3031 (1373)
E2212 / C2212
20.8 (528.1) 30.6 (778.0)
3071 (1391)
3200 (1440)
063
3031 (1373)
E2612 / C2212
20.8 (528.1) 30.6 (778.0)
3880 (1758)
3200 (1440)
063
3900 (1767)
E2612 / C2612
20.8 (528.1) 30.6 (778.0)
3880 (1758)
3200 (1440)
063
3900 (1767)
E3012 / C2612
20.8 (528.1) 30.6 (778.0)
5075 (2299)
3200 (1440)
079
2511 (1137)
E2209 / C2209
18.8 (476.5) 29.1 (739.6)
2708 (1227)
3200 (1440)
079
2511 (1137)
E2609 / C2209
18.8 (476.5) 29.1 (739.6)
3381 (1532)
3200 (1440)
079
3210 (1454)
E2609 / C2609
18.8 (476.5) 29.1 (739.6)
3381 (1532)
3200 (1440)
079
3210 (1454)
E3009 / C2609
18.8 (476.5) 29.1 (739.6)
4397 (1992)
3200 (1440)
079
4356 (1973)
E3009 / C3009
18.8 (476.5) 29.1 (739.6)
4397 (1992)
3200 (1440)
079
4356 (1973)
E3609 / C3009
19.8 (501.9) 26.7 (678.9)
5882 (2665)
3200 (1440)
079
3031 (1373)
E2212 / C2212
18.8 (476.5) 29.1 (739.6)
3071 (1391)
3200 (1440)
079
3031 (1373)
E2612 / C2212
18.8 (476.5) 29.1 (739.6)
3880 (1758)
3200 (1440)
079
3900 (1767)
E2612 / C2612
18.8 (476.5) 29.1 (739.6)
3880 (1758)
3200 (1440)
079
3900 (1767)
E3012 / C2612
18.8 (476.5) 29.1 (739.6)
5075 (2299)
3200 (1440)
079
5333 (2416)
E3012 / C3012
18.8 (476.5) 29.1 (739.6)
5075 (2299)
3200 (1440)
079
5333 (2416)
E3612 / C3012
19.8 (501.9) 26.7 (678.9)
6840 (3099)
3200 (1440)
087
2511 (1137)
E2609 / C2209
19.8 (501.9) 26.7 (678.9)
3381 (1532)
3200 (1440)
087
3210 (1454)
E2609 / C2609
19.8 (501.9) 26.7 (678.9)
3381 (1532)
3200 (1440)
087
3210 (1454)
E3009 / C2609
19.8 (501.9) 26.7 (678.9)
4397 (1992)
3200 (1440)
087
4356 (1973)
E3009 / C3009
19.8 (501.9) 26.7 (678.9)
4397 (1992)
3200 (1440)
087
4356 (1973)
E3609 / C3009
19.8 (501.9) 26.7 (678.9)
5882 (2665)
3200 (1440)
087
3031 (1373)
E2612 / C2212
19.8 (501.9) 26.7 (678.9)
3880 (1758)
3200 (1440)
087
3900 (1767)
E2612 / C2612
19.8 (501.9) 26.7 (678.9)
3880 (1758)
3200 (1440)
087
3900 (1767)
E3012 / C2612
19.8 (501.9) 26.7 (678.9)
5075 (2299)
3200 (1440)
087
5333 (2416)
E3012 / C3012
19.8 (501.9) 26.7 (678.9)
5075 (2299)
3200 (1440)
087
5333 (2416)
E3612 / C3012
19.8 (501.9) 26.7 (678.9)
6840 (3099)
3200 (1440)
087
7508 (3401)
E3612 / C3612
19.8 (501.9) 26.7 (678.9)
6840 (3099)
3200 (1440)
100
5333 (2416)
E3012 / C3012
19.8 (501.9) 34.8 (884.4)
5075 (2299)
6000 (2700)
100
5333 (2416)
E3612 / C3012
19.8 (501.9) 34.8 (884.4)
6840 (3099)
6000 (2700)
100
7508 (3401)
E3612 / C3612
19.8 (501.9) 34.8 (884.4)
6840 (3099)
6000 (2700)
100
7508 (3401)
E4212 / C3612
19.8 (501.9) 34.8 (884.4)
8922 (4042)
6000 (2700)
100
10267 (4651)
E4212 / C4212
19.8 (501.9) 34.8 (884.4)
8922 (4042)
6000 (2700)
100
10267 (4651)
E4812 / C4212
19.8 (501.9) 34.8 (884.4)
11125 (5040)
6000 (2700)
113
5333 (2416)
E3012 / C3012
19.8 (501.9) 34.8 (884.4)
5075 (2299)
6000 (2700)
113
5333 (2416)
E3612 / C3012
19.8 (501.9) 34.8 (884.4)
6840 (3099)
6000 (2700)
113
7508 (3401)
E3612 / C3612
19.8 (501.9) 34.8 (884.4)
6840 (3099)
6000 (2700)
113
7508 (3401)
E4212 / C3612
19.8 (501.9) 34.8 (884.4)
8922 (4042)
6000 (2700)
113
10267 (4651)
E4212 / C4212
19.8 (501.9) 34.8 (884.4)
8922 (4042)
6000 (2700)
113
10267 (4651)
E4812 / C4212
19.8 (501.9) 34.8 (884.4)
11125 (5040)
6000 (2700)
113
13077 (5924)
E4812 / C4812
19.8 (501.9) 34.8 (884.4)
11125 (5040)
6000 (2700)
126
5333 (2416)
E3612 / C3012
19.8 (501.9) 34.8 (884.4)
6840 (3099)
6000 (2700)
126
7508 (3401)
E3612 / C3612
19.8 (501.9) 34.8 (884.4)
6840 (3099)
6000 (2700)
126
7508 (3401)
E4212 / C3612
19.8 (501.9) 34.8 (884.4)
8922 (4042)
6000 (2700)
126
10267 (4651)
E4212 / C4212
19.8 (501.9) 34.8 (884.4)
8922 (4042)
6000 (2700)
126
10267 (4651)
E4812 / C4212
19.8 (501.9) 34.8 (884.4)
11125 (5040)
6000 (2700)
126
13077 (5924)
E4812 / C4812
19.8 (501.9) 34.8 (884.4)
11125 (5040)
6000 (2700)
Notes:
1.
The overall vessel length can vary depending on the specified tube length and pass arrangement. Consult the McQuay certified
submittal drawings, or unit dimensions beginning on page 66 in this catalog for specific vessel lengths.
2.
The oil pump width is the dimension from front to back. The height is from the bottom of the sump to the top of the control box located to
the right of the sump. Transporting the oil pump is usually not an issue when compared to the vessels.
3.
Allow plus / minus 1 inch (24.5mm) for manufacturing tolerance.
4.
All dimensions are shown in inches (mm).
5.
All weights are shown in lbs. (kg).
Catalog WSC/WDC-4
35
Pumpdown
Pumpout systems provide a means to collect and contain the refrigerant charge without loss,
when the access to internal chiller components is required for service.
McQuay condensers are sized to hold the entire unit refrigerant charge when not more than 90%
full at 90°F (32°C) ambient temperature. They are equipped with a tight-seating check valve at
the hot gas inlet and a manual shutoff valve in the liquid outlet. These valves, coupled with the
condenser design, satisfy the stringent requirements of the U.S. Department of Transportation for
refrigerant shipping containers, as well as ASME vessel codes. When service is required, the
refrigerant charge can be pumped down into the condenser by compressor operation and use of a
refrigerant transfer unit. All dual compressor units and single compressor units equipped with an
optional suction shutoff valve can also be pumped down to the evaporator. Elimination of the cost
and space requirements of an external pumpout system is a major McQuay advantage.
Electronic Expansion Valves
Controlled refrigerant flow over the entire capacity range saves energy and dollars.
Cooling loads and condenser water temperatures can change constantly. Refrigerant float valves
and orifices on competitive chillers are typically selected for peak load and peak condenser water
temperatures and offer only partial control of refrigerant flow at operating conditions experienced
over 95% of the time.
On McQuay chillers, modern, electronic or thermal expansion valves (depending on unit size)
meter refrigerant flow in direct response to load and unit conditions. In doing so, full utilization
of compressor, evaporator, and condenser efficiency over the entire operating range is achieved.
Intermittent refrigerant flood-back and excessive superheat characteristic of orifices and floats are
greatly reduced.
Factory Performance Test
Fast and trouble-free startup and operation.
All McQuay chillers are factory tested on ARI certified, microprocessor controlled, test stands.
The test stand microprocessors interface with the chiller MicroTech II controls, allowing
monitoring of all aspects of the test stand and chiller operation.
The test procedure starts with dehydration and evacuation of the refrigerant circuit and charging
with refrigerant and lubricant. This is followed by a run test at job conditions of flow and
temperature. Compressors must meet a stringent 0.14 in/sec vibration limit and the entire unit
must pass a moisture limit of 30 ppm. The testing helps ensure correct operation prior to
shipment, and allows factory calibration of chiller operating controls.
36
Catalog WSC/WDC-4
Options and Accessories
Vessels
Marine water boxes
Provides tube access for inspection, cleaning, and removal without dismantling water piping.
Flanges (Victaulic® connections are standard)
ANSI raised face flanges on either the evaporator or condenser. Mating flanges are by others.
0.028 or 0.035 in. tube wall thickness
For applications with aggressive water conditions requiring thicker tube walls.
Cupro-nickel or titanium tube material
For use with corrosive water conditions, includes clad tube sheets and epoxy coated water heads.
Water-side vessel construction of 300 psi (150 psi is standard)
For high pressure water systems, typically high-rise building construction.
Water differential pressure switches
This option provides evaporator and condenser water pressure differential switches as a factory
mounted and wired option. A proof-of-flow device is mandatory in both the chilled water and
condenser water systems.
Single insulation, ¾-inch, on evaporator, suction piping, and motor barrel
For normal machine room applications.
Double insulation, 1-½ inch, on evaporator, suction piping, and motor barrel
For high humidity locations and ice making applications.
Electrical
Optional starters for factory or field mounting
See details in the Motor Starter section of this manual and catalog PM Starter.
Variable frequency drives (VFD)
Efficiency: The variable frequency drive option is a technology that has been used for decades to
control motor speed on a wide variety of motor-drive applications. When applied to centrifugal
compressor motors, significant gains in compressor part load performance can be realized. The
improvement in efficiency and reduction of annual energy cost is maximized when there are long
periods of part load operation, combined with low compressor lift (lower condenser water
temperatures). When atmospheric conditions permit, McQuay chillers equipped with VFDs can
operate with entering condenser as low as 50°F (10°C), which results in extremely low kW/ton
values.
Combining the attributes of VFD drives and the extremely efficient McQuay WDC Dual
Centrifugal Chiller produces the industry's most efficient chiller based on the all-important IPLV
value. See “IPLV/NPLV Defined” on page 49 for details on the ARI IPLV efficiency rating.
Water-Side Economizers: Free cooling systems utilizing cold cooling tower water to remove heat
from the chilled water system through a heat exchanger are becoming popular because the ability
of a chiller to move seamlessly from mechanical cooling to the free cooling mode is an important
operational feature. When equipped with a VFD, McQuay chillers can operate with condenser
water down to 50°F (10°C) at which point the economizer heat exchanger can be activated and the
free cooling can go into effect.
Starting Inrush: The use of a VFD on centrifugal chillers also provides an excellent method of
reducing motor starting inrush, even better than solid state starters. Starting current can be closely
controlled since both the frequency and voltage are regulated. This can be an important benefit to
a building's electrical distribution system.
Sound: The sound level of centrifugal compressors is largely dependent on the impeller tip speed.
By reducing compressor speed the sound level is also reduced.
Catalog WSC/WDC-4
37
NEMA 4 watertight enclosure
For use where there is a possibility of water intrusion into the control panel.
NEMA 12 Dust tight enclosure
For use in dusty areas.
Controls
English or Metric Display
Either English or metric units for operator ease of use.
BAS interface module for the applicable protocol being used.
Factory-installed on the unit controller (can also be retrofitted). See page 21 for details.
Unit
Export packaging
Can be either slat or full crate for additional protection during shipment. Units normally shipped
in containers.
Pumpout Unit, Model RRU with or without storage vessel
Available in a variety of sizes. Details under the Pumpout section on page 45 of this manual.
Refrigerant monitor
For remote mounting, including accessories such as 4-20ma signal, strobe light, audible horn, air
pick-up filter. Details on page 47.
Hot gas bypass
For operation below 10% on WSC and 5% on WDC units. Reduces compressor cycling and its
attendant chilled water temperature swings.
Sound attenuation package
Consists of acoustical insulation on the discharge line.
Extended warranties
Extended 1, 2, 3, or 4-year warranties for parts only or for parts and labor are available for the
entire unit or compressor/motor only.
Optional Certified Test
A McQuay engineer oversees the testing, certifies the accuracy of the computerized results, and
then translates the test data onto an easy-to-read spreadsheet. The tests can be run at ARI load
points between 10% and 100% and are run to ARI tolerance of capacity and power. 50 Hz units
are run tested at 60 Hz to their maximum motor power.
Optional Witness Test
A McQuay engineer oversees the testing in the presence of the customer or their designate and
translates the test data onto an easy-to-read spreadsheet. The tests can be run at ARI load points
between 10% and 100%. It takes two to three hours of test time per load point specified. Tests are
run to ARI tolerances of capacity and power. 50 Hz units can be run-tested at 50 Hz using an
onsite 50 Hz generator.
38
Catalog WSC/WDC-4
Motor Controllers
Motor Starters
McQuay has a wide variety of starter types and options to fit virtually all applications. The
specifics of the final selection of size, enclosure, and options are covered in the catalog PM
Starters. Please consult the local McQuay sales office or the starter catalog for starter details.
This section contains a general overview only.
Mounting Options, Low Voltage, 200 to 600 Volts
Factory-mounted; starters furnished, mounted and wired in the factory. Due to shipping width
limitations, the starters for WSC 100 through 126 are shipped loose with cable kits and mounting
brackets for field installation and connection on the units by others.
Freestanding; furnished by McQuay and drop shipped to the job site for setting and wiring by
others.
Starters by others; starters furnished by others must meet McQuay Specification R35999901,
available from the local McQuay sales office. The starters are furnished and installed by others.
Table 4, Starter Mounting Arrangements
Size
FactoryMounted
FreeStanding
WSC/WDC 050-087
X
X
WSC 100-126
X
WDC 100-126
X
Brackets &
Cables
X
Mounting Options, Medium Voltage, 2300 to 6000 Volts
All starter types in these voltages are for field setting and wiring only.
Starter Types and Descriptions
Solid state starters are available for both low and medium voltages and are similar in construction
and features regardless of voltage.
For low voltage application, Wye-Delta Closed Transition starters are available, in addition to
solid state.
For medium voltage application, autotransformer, primary reactor reduced voltage and across-theline starters are offered in addition to solid state.
Variable Frequency Drives (VFD)
VFDs are available on all McQuay chillers including up to 2500 tons. The fact that the larger
chillers have dual compressors allows the VFD option at a reasonable price.
Catalog WSC/WDC-4
39
Variable Frequency Drives
Impact of Variable Frequency Drives
The chart below illustrates the relative IPLV efficiencies of various McQuay options for a typical
500-ton selection. The chiller cost increases as the efficiency improves.
Comparative Efficiencies (kW/Ton)
.6
.505
IPLV
.5
.403
.4
.365
.337
.3
WSC
WDC
WSC w/VFD
WDC w/VFD
Notes: WSC = Single Compressor Centrifugal Chiller
WDC = Dual Compressor Centrifugal Chiller
VFD = Variable Frequency Drive
The IPLV values (defined on page 49) are ARI Certified Ratings based on ARI Standard 550/5901998, Standard for Water Chilling Packages Using the Vapor Compression Cycle. Full load is at
44°F chilled water temperature with 2.4 gpm/ton, 85°F entering condenser water temperatures
with 3 gpm/ton. Part load points of 75%, 50%, and 25% employ condenser water temperature
relief (reduction) per the standard.
General
Single and dual compressor units can be equipped with a variable frequency drive (VFD). A VFD
modulates the compressor speed in response to load and evaporator and condenser pressures as
sensed by the microprocessor. Due to the outstanding part load efficiency, and despite the small
power penalty attributed to the VFD, the chiller can achieve outstanding overall efficiency. VFDs
really prove their worth when there is reduced load combined with low compressor lift (lower
condenser water temperatures) dominating the operating hours.
The traditional method of controlling centrifugal compressor capacity is by inlet guide vanes.
Capacity can also be reduced by slowing the compressor speed and reducing the impeller tip
speed, providing sufficient tip speed is retained to meet the discharge pressure requirements. This
method is more efficient than guide vanes by themselves.
In actual practice a combination of the two techniques is used. The microprocessor slows the
compressor (to a fixed minimum percent of full load speed) as much as possible, considering the
need for tip speed to make the required compressor lift. Guide vanes take over to make up the
difference in required capacity reduction. This methodology provides the optimum efficiency
under any operating condition.
40
Catalog WSC/WDC-4
Standard Components
1)
2)
3)
4)
5)
6)
7)
8)
9)
Incoming and outgoing power terminals.
Transformer to supply power to the control circuit, oil heaters and oil pump.
Redundant motor control relays with coils in series.
The VFD is current rated at 2 kHz carrier frequency for all 200–1000 HP drives. The drive is
capable of running at 110% of nameplate current continuously and provides a minimum of
150% of this rated current for 5 seconds.
The VFD will not generate damaging voltage pulses at the motor terminals when applied
within 500 feet of each other. Both drive and motor comply with NEMA MG1 section
30.40.4.2 which specifies these limits at a maximum peak voltage of 1600 Volts and a
minimum rise time of .1 microseconds.
Units drawing 240 amps or less are air-cooled. All others are water-cooled. Factory-mounted
water-cooled VFDs are factory piped to the chiller oil cooling system. Free-standing watercooled units require chilled water supply and return piping for the VFD cooling. VFDs have
a liquid-cooled heat sink assembly enabling liquid cooling of the drive through a single inlet
and outlet connection point, dissipating 25,000 BTUs/Hr for 600 HP, 20,000 BTUs/Hr for
450 HP, and 16,000 BTUs/Hr for 350 HP. The cooling circuit maintains water temperature
between 60°F and 104°F (15°C to 40°C).
The VFD and options are cUL¥ 508 listed. The drive and options are designed to comply
with the applicable requirement of the latest standards of ANSI, NEMA, National Electric
Code NEC, NEPU-70, IEEE 519-1992, FCC Part 15 Subpart J, CE 96.
The VFD is functionally tested under motor load. During this load test, the VFD is
monitored for correct phase current, phase voltages, and motor speed. Correct current limit
operation is verified by simulating a motor overload. Verification of proper factory presets
by scrolling through all parameters is performed to check proper microprocessor settings.
The computer port also verifies that the proper factory settings are loaded correctly in the
drive.
The VFD has the following basic features:
a) An overload circuit to protect an AC motor operated by the VFD output from extended
overload operation on an inverse time basis. This electronic overload is UL¥ and NEC
recognized as adequate motor protection. No additional hardware such as motor overload
relays or motor thermostats are required.
b) An LED display that digitally indicates:
Frequency output
Voltage output
Current output
Motor RPM
Input kW
Elapsed time
Time-stamped fault indication
DC bus volts
c) The capability of riding though power dips up to 10 seconds without a controller trip,
depending on load and operating condition.
d) RS232 port and Windows® based software for configuration, control, and monitoring.
e) An isolated 0-20mA, 4-20 mA or 0-4, 0-8, 0-10 volt analog speed input follower.
f) An isolated 0-10 V or 4-20 mA output signal proportional to speed or load.
Catalog WSC/WDC-4
41
g) Standard input/output (I/O) Expansion Interface Card with the following features:
−
−
−
−
−
−
−
10)
Proportional/integral (PI) regulator for setpoint control
Four isolated 24 VDC programmable digital inputs
An additional analog input for speed feedback to PI regulator
One frequency input (0 to 200 Hz) for digital control of current limit
Four programmable isolated digital outputs (24 VDC rated)
One form A output relay rated at 250 VAC or 24 VDC
Two NO/NC programmable output relays rated at 250 VAC or 24 VDC
The VFD includes the following protective circuits and features:
a) Motor current exceeds 200% of drive continuous current rating.
b) Output phase-to-phase short circuit condition.
c) Total ground fault under any operating condition.
d) High input line voltage.
e) Low input line voltage.
f) Loss of input or output phase.
g) External fault. (This protective circuit permits wiring of a remote NC safety contact to
shut down the drive).
h) Metal oxide varistors for surge suppression are provided at the VFD input terminals.
Options
Reactor
Used for control of line harmonics in some installations.
Incoming Line Termination (Chose one)
•
•
•
•
•
•
Terminal block
Non-fused disconnect with through-the-door handle
Fused disconnect with time delay fuses with through-the-door handle
Standard interrupting circuit breaker with through-the-door handle
High interrupting circuit breaker with through-the-door handle
Ultra high circuit breaker with through-the-door handle
Volts/Amps Meter with 3-phase Switch
General Arrangement
VFD Mounting
VFDs from size VFD 019 through VFD 072 can be factory-mounted on the same units and in the same
location as conventional starters or can be free-standing as shown below. Sizes VFD 090 through 120
are for free-standing only. Dimensions begin on page 66.
Chiller Model
WSC, WDC 050-087
WSC 100-126
WDC 100-126
Unit Mounted at
Factory (1)
X
Unit Mounted in
Field
X (3)
Free-Standing
(2)
X
X
X
Notes
1. Optional reactor is field-mounted and wired to unit mounted VFD.
2. Optional reactor is factory-mounted in the VFD enclosure.
3. Brackets and interconnecting cables shipped with unit.
42
Catalog WSC/WDC-4
VFD Line Harmonics
Care must be taken when applying VFDs due to the effect of line harmonics on the 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 may be critical to AC drive users 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.
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. Mount the drive far from the source transformer.
2. Add line reactors.
3. Use an isolation transformer.
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 may be done in the following ways:
1. Keep the PCC as far from the drives (close to the power source) as possible.
2. Increase the size (decrease the impedance) of the source transformer.
3. Increase the capacity (decrease the impedance) of the busway or cables from the source to the
PCC.
4. Make sure that added reactance is downstream (closer to the VFD than the source) from the PCC.
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 may be required on some
installations.
Catalog WSC/WDC-4
43
Figure 12, VFD (047 and Larger) Cooling Water Piping for Free-Standing VFD
* STOP
CHILLED
WATER
PUMP
VALVE
* BALANCING
* STOP
VALVE
VALVE
CHILLER
WATER
REGULATING
VALVE
(Factory Mounted)
VFD HEAT
EXCHANGER
SOLENOID
VALVE
(Factory Mounted)
* STOP
VALVE
* STRAINER
* Field Supplied Piping Components
* STOP
* DRAIN VALVE
MAX. 40 MESH
VALVE
OR PLUG
OIL COOLER CIRCUIT
SOLENOID
VALVE
(Factory Mounted)
WATER
REGULATING
VALVE
(Factory Mounted)
Table 5, Cooling Requirements
Combined
Compressor Oil
McQuay
Drive Model and VFD Cooling
Copper Tube Size
Number
Type K or L
VFD 019
N/A
VFD 025
N/A
VFD 047
1.0
VFD 060
1.0
VFD 072
1.0
VFD 090
1 1/4
VFD 120
1 1/4
VFD Cooling
Only Copper
Tube Size
Type K or L
Coolant
Method
N/A
N/A
7/8 in.
7/8 in.
7/8 in.
1.0 in.
1.0 in.
Air
Air
Water (1)
Water (1)
Water (1)
Water (1) (3)
Water (1) (3)
Max.
Entering
Coolant
Temperature
(°F)
104
104
90
90
90
90
90
Min. Entering
Coolant
Temperature
(°F)
Required
Pressure
Drop
feet
Maximum
Pressure
(Water
Side) psi
40
40
40
40
40
40
40
NA
NA
10 (2)
30 (2)
30 (2)
30 (2)
30 (2)
N/A
N/A
300
300
300
300
300
Notes:
1. Cooling water must be from the closed, chilled water circuit with corrosion inhibitors for steel and copper, and must be piped
across the chilled water pump.
2. The required pressure drop is given for the maximum coolant temperature. The water regulating valve will reduce the flow
when the coolant temperature is below the maximum in the table. The pressure drop includes the drop across the solenoid
valve, heat exchanger and water regulating valve.
3. Models VFD 090and 120 have a separate self-contained cooling loop with a recirculating water pump and heat exchanger, but
are piped the same as all water-cooled VFDs.
Table 6, Cooling Water Connection Sizes
Chiller Unit
WDC 100/126
WSC/WDC 050
All Others
44
Free-Standing VFD
Oil Cooler
VFD
1 1/2 in. FPT
3/4 in. MPT
Not Required
Air-Cooled
1 in. FPT
3/4 in MPT
Factory-Mounted VFD
Combined
1 1/2 in. FPT
Not Required
1 in. FPT
Catalog WSC/WDC-4
Refrigerant Recovery Units
Although McQuay chillers can pump the entire refrigerant charge into the condenser and valve it off, there
are occasions when pumpout units are required, due purely to specification requirements or unusual job
considerations.
McQuay offers two sizes of refrigerant recovery units (Model RRU) and one recovery unit that is factory
mounted on a storage vessel (Model PRU). Recovery units are ETL listed. Capacities for R-22 are ARI
certified. The storage tank is designed, constructed and stamped in accordance with ASME standards.
Model RRU Refrigerant Recovery Units
Size and Specifications
Model
RRU134-5
RRU134-3
(1) R-22 Liquid
Transfer Rate
lb/m (kg/m)
55 (25)
55 (25)
(1) R 22 Vapor
Transfer Rate
lb/m (kg/m)
1.56 (0.71)
1.56 (0.71)
Comp.
HP
(2) Chiller
Tons (kW)
Weight
lbs (kg)
1.5
1.5
300 (1050)
300 (1050)
115 (52)
115 (52)
Dimensions
LxWxH
Inch (cm)
21 x 14 x 19 (53 x 36 x 68)
21 x 14 x 19 (53 x 36 x 68)
RRU570-3
325 (148)
6.0 (2.7)
3
1000 (3500)
190 (86)
26 x 25 45 (66 x 63 x 114)
RRU570-V
325 (148)
6.0 (2.7)
3
1000 (3500)
190 (86)
26 x 25 45 (66 x 63 x 114)
RRU570-R
325 (148)
6.0 (2.7)
3
1000 (3500)
190 (86)
26 x 25 45 (66 x 63 x 114)
RRU570-D
325 (148)
6.0 (2.7)
3
1000 (3500)
190 (86)
26 x 25 45 (66 x 63 x 114)
NOTES:
1. Transfer rate for R-22 is ARI certified. R-134a capacity is given below in each unit's description.
2. Suggested maximum chiller capacity.
Electrical
1/50-60/110-115
1/50-60/220-230
1/50-60/220-230
3/50-60/220-230
3/50-60/360-460
3/60/575
Refrigerant Compatibility
Units are suitable for use with the following refrigerants normally found on McQuay chillers; R-12, R-22, R134a, R-410A, and R-500.
Standard Equipment
Equipment
Model
RRU134
RRU570
Power Cord
X
X
Filter-Driers
(2) 30 cu. in.
(1) 48 cu. in
X
X
(4) 10 ft.
(1) 10 ft + (2) 20 ft
Electromechanical Control
Hoses
Reducing Fittings
X
12 ft. Tank Float Switch Cable
X
Connection Sizes
½ in. Flare
¾ in. Flare
Model RRU134
Large 1 ½-HP open drive compressor, ½-inch lines, two-point
vapor extraction and oversized air-cooled condenser speed
recovery on smaller size chillers. Purging and switching from
liquid to vapor recovery only involves turning 3-way valvesno switching of hoses is necessary. Capacity with R-134a is
55 lb/min liquid, 1.34 lb/min vapor.
Catalog WSC/WDC-4
45
MODEL RRU570
Recovers at R-134a at 300 lb/min liquid and 5.7 lb/min vapor,
ideal for the medium size chiller job. Rugged 3 hp open-drive
compressor provides years of reliable service, even on
refrigerants heavily contaminated with oil, air, moisture, or acids.
Purging and switching from liquid to vapor recovery only
involves turning 3-way valves-no switching of hoses is
necessary. Suitable for most high pressure refrigerants and
blends. Equipped with air-cooled condenser.
Model PRU Packaged Recovery Units
The Model RRU134 transfer unit can be factory-mounted on a storage vessel providing a packaged unit
with a R-134a transfer capacity of 55 lb/min liquid and 1.34 lb/min of vapor combined with a storage
vessel with a capacity of 2105 pounds of R-134a. Includes (2) 20-ft. hoses.
Model
R-22 Liquid
Transfer Rate
lb/m (kg/m)
R-22 Vapor
Transfer Rate
lb/m (kg/m)
Weight
lb (kg)
Length
in (cm)
Width
in (cm)
Height
in (cm)
Electrical
PRU134-5
55 (25)
1.56 (0.71)
770 (349)
94 (239)
30 (76)
55 (139)
1/50-60/110-115
PRU134-3
55 (25)
1.56 (0.71)
770 (349)
94 (239)
30 (76)
55 (139)
1/50-60/220-230
Unit
Accessories
46
RHK-120
1.25 in. x 10 ft. hose with ball valves
RHK-240
1.25 in. x 20 ft. hose with ball valves
Catalog WSC/WDC-4
Refrigerant Monitors
Detects all halogen based refrigerants
Optional analog output for remote monitoring
Visual alarm indication
Fresh air inlet for automatic re-zeroing
ETL listed
Continuous digital display of system status
System malfunction detection and indication
Can sample up to 250 feet (76 meters) away
Multi-unit capability in a single monitor
UL STD 3101-1 and CAN/CSA 1010.1
MODELS
Model RM-1 1 Zone Monitor
Model RM-4 4 Zone Monitor
Model RM-8 8 Zone Monitor
Model RM-16 16 Zone Model
SPECIFICATIONS
Sensitivity: As low as 1 PPM
Range: 0 to 1000 PPM
Weight: 25 lbs. (11 kg)
Power: 120/240 Volt, 50/60 Hz
Operating Environment: 32°F-125°F
Size: W=16.5in. D=6.75in. H=15in.
Alarm Trip Points (Percent of Full Scale): Low Alarm=0 to 100, Main Alarm=0 to 100, High Alarm=100
Alarm Outputs: Indicator Light, Alarm Relays, RS232 Computer Interface
OPTIONS and ACCESSORIES
Analog Output, 4-20 ma (RMA-AO)
Remote Strobe Light, 120 V (RMA-L)
Remote Horn, 120V (RMA-H)
Remote Light and Horn Set (RMA-LH)
Plastic Pick-up Tubing, ¼ inch OD, 250 ft. Reel (RMA-T)
Diaphragm Pump (RMA-P) *
Course Replacement Filter (RMA-CF) *
5 Micron Replacement Filter (RMA-F) *
(*) Replacement parts. Original pump and filters are shipped with unit.
Catalog WSC/WDC-4
47
Unit Selection
Many combinations of compressor configuration
and condensers and evaporators are available for a
given capacity. The units range from low first cost
and relatively high kW per ton (COP) to high first
cost and low kW per ton (COP). A graphic display
of the optional performance available is shown at
the right. The COP curve would be mirrored and is
not shown for clarity. Optimum unit selection for
maximum operating return on the invested first cost
is in the area identified by the X.
Actual optimum unit selection will vary with
building
application
and
system
design.
Applications with minimal hours of operation
cannot justify a very low kW per ton (COP) unit.
Applications with high hours of operation will
justify high part load as well as full load efficiency units. For optimum selection an energy
analysis is available through your local McQuay Sales Representative.
Basic unit selections
All McQuay centrifugal chillers are computer selected to optimize the cooling output and total
kW. Computer selection allows for the specification of leaving chilled water temperature, entering
condenser water temperature, evaporator and condenser flow rates, number of passes, and fouling
factors. Glycol applications can also be specified.
Glycol operation
The addition of glycol to the chilled water system for freeze protection can be required for special
applications. Glycol solutions are required where the evaporating temperatures are below 33°F
(1°C).
ARI Certification
McQuay International has an on-going commitment to supply chillers that perform as specified.
To this extent, McQuay centrifugal chillers are part of the ARI Certification. On-going
performance verification of chiller capacity and power input plus ARI certified computerized
selection output provide the owner with specified performance in accordance with the latest
version of ARI Standard 550/590.
All chillers that fall within the scope of the certification program have an ARI certification label at
no cost to the owner. Equipment covered by the ARI certification program include all watercooled centrifugal and screw water chilling packages rated up to 2000 tons (7,000 kW) for 60
Hertz service at ARI standard rating conditions, hermetic or open drive, with electric driven motor
not exceeding 5000 volts, and cooling water (not glycol). For 50 hertz application the capacity
range covered is 200 to 1,000 tons (700 to 3500 kW).
Published certified ratings verified through testing by ARI include:
•
Capacity, tons (kW)
• Power, kW/ton (COP)
• Pressure drops, ft. of water (kPa)
• Integrated Part Load Value (IPLV) or Non-Standard Part Load Value (NPLV)
As part of the ARI certification program, ARI has the McQuay computer selection program used
to select and rate chillers. The certified computer program version number and issue date for all
manufacturers is listed in the ARI Directory of Certified Applied Air-Conditioning Products
available on www.ari.org.
48
Catalog WSC/WDC-4
ARI Standard 550/590-98 for Centrifugal or Screw Water-Chilling Packages and associated
manuals define certification and testing procedures and performance tolerances of all units that
fall within the application rating conditions.
Leaving chilled water temperature ......................... 40°F to 48°F (4.4°C to 8.9°C)
Entering condenser water temperature ................... 60°F to 95°F (15.6°C to 35°C)
Rating outside the range of the certification program can be listed or published but must include a
statement describing such. The standard rating conditions are:
Leaving chilled water temperature ......................... 44°F (6.7°C)
Evaporator waterside field fouling allowance........ 0.0001 ft2 x hr x°F/BTU (0.0176 m2 x °C/kW
Chilled water flow rate ........................................... 2.4 gpm/ton (0.043 l/s / kW)
Entering condenser water temperature ................... 85°F (29.4°C)
Condenser waterside field fouling allowance ........ 0.00025 ft2 x hr x°F/BTU (0.044 m2 x °C/kW
Condenser water flow rate ..................................... 3.0 gpm/ton (0.054 l/s / kW)
IPLV/NPLV Defined
Part load performance can be presented in terms of Integrated Part Load Value (IPLV), which is
based on ARI standard rating conditions (listed above), or Non-Standard Part Load Values
(NPLV), which is based on specified or job site conditions. IPLV and NPLV are based on the
following equation from ARI 550/590.
IPLV
or
NPLV
=
1
0.01 0.42 0.45 0.12
+
+
+
A
B
C
D
or
0.01A + 0.42 B + 0.45C + 0.12 D
Where: A = kW/ton at 100%
B = kW/ton at 75%
C = kW/ton at 50%
D = kW/ton at 25%
Where: A = COP at 100%
B = COP at 75%
C = COP at 50%
D = COP at 25%
Weighting
The percent of annual hours of operation at the four load points are as follows:
100% Load at 1%,
75% Load at 42%,
50% Load at 45%,
25% Load at 12%
Tolerances
The ARI test tolerance, per ARI Standard 550/590-98, for capacity (tons), power input per ton
(kW/ton), and heat balance is:
1500
§
·
% Tolerance = 10.5 − (0.07 x % FL ) + ¨
¸
© DTFLx % FL ¹
Where: FL = Full Load
DTFL = Chilled Water Delta-T at Full Load
This formula results in a ±5% tolerance on tons and kW/ton at the 100% load point and ARI
conditions.
Certification
Full ARI 550/590 participation and certification has been an on-going commitment at McQuay International. The ARI label affixed to
certified units certifies that the unit will meet the specified performance. This equipment is certified in accordance with ARI Standard
550/590, latest edition, provided the application ratings are within the scope of the certification program.
The program excludes the following applications: air and evaporative cooled chillers, capacity exceeding 2000 tons (7000 kW) on 60
hertz service, voltages above 5000 volts, brine and special fluids other than water and heat recovery units. The capacity range for 50
hertz is 200 to 1,000 tons (700 to 3500 kW).
Catalog WSC/WDC-4
49
Application Considerations
Optimum Water Temperatures and Flow Rates
A key to improving energy efficiency for any chiller is minimizing the lift, or pressure difference,
between the compressor suction and discharge pressures. Reducing the lift reduces the
compressor work, and hence its energy consumption per unit of output. The chiller typically has
the largest motor of any component in a chilled water system.
Higher leaving chilled water temperatures
Warmer leaving chilled water temperatures will raise the compressor’s suction pressure and
decrease the lift, improving efficiency. Using 45°F (7.0°C) leaving water instead of 42°F (5.5°C)
will make a significant improvement.
Evaporator temperature drop
The industry standard has been a ten-degree temperature drop in the evaporator. Increasing the
drop to 12 or 14 degrees will improve the evaporator heat transfer, raise the suction pressure, and
improve chiller efficiency. Chilled water pump energy will also be reduced.
Condenser entering water temperature
As a general rule, a one-degree drop in condenser entering water temperature will reduce chiller
energy consumption by two percent. Cooler water lowers the condensing pressure and reduces
compressor work. One or two degrees can make a noticeable difference. The incremental cost of
a larger tower can be small and provide a good return on investment.
Condenser water temperature rise
The industry standard of 3 gpm/ton or about a 9.5-degree delta-T seems to work well for most
applications. Reducing condenser water flow to lower pumping energy will increase the water
temperature rise, resulting in an increase in the compressor’s condensing pressure and energy
consumption. This is usually not a productive strategy.
System analysis
Although McQuay is a proponent of analyzing the entire system, it is generally effective to place
the chiller in the most efficient mode because it is, by far, a larger energy consumer than pumps.
The McQuay Energy Analyzer™ program is an excellent tool to investigate the entire system
efficiency, quickly and accurately. It is especially good at comparing different system types and
operating parameters. Contact you local McQuay sales office for assistance on your particular
application.
For Best Chiller Efficiency
Vessel
Evaporator
Evaporator
Evaporator
Condenser
Condenser
Activity
Higher leaving water Temperatures
Higher water temperature drops
Lower flow rates
Lower entering water temperature
Higher flow rates (3.0 gpm/ton or higher)
Example
44°F instead of 42°F
12 degrees F instead of 10 degrees
2.4 gpm/ton instead of 3.0 gpm/ton
84°F instead of 85°F
3.0 gpm/ton instead of 2.5 gpm/ton
The designer must determine the proper chiller efficiency for a given application. The most
efficient chiller is not always the best. A life cycle analysis (as performed by McQuay’s Energy
Analyzer program, for example) is the only way to be sure of the best selection. Utility costs, load
factors, maintenance costs, cost of capital, tax bracket; in other words, all the factors affecting
owning cost, must be considered.
Generally, the attempts to save the last few full load kW are very costly. For example, the cost to
go from 0.58 to 0.57 kW/ton could be very costly because of the large number of copper tubes that
would have to be added to the heat exchangers.
50
Catalog WSC/WDC-4
Low Condenser Water Temperature Operation
When ambient wet bulb temperature are lower than design, the condenser water temperature can
be allowed to fall. Lower temperatures will improve chiller performance.
Up to 300 Tons
McQuay centrifugal chillers up to 300 tons are equipped with electronic expansion valves (EXV)
and will start and run with entering condenser water temperatures as low as shown in Figure 13 or
as calculated from the following equation on which the curves are based.
Figure 13, Minimum Entering Condenser Water Temperature (EXV)
Minimum Entering Condenser Water Temperature - 10 F Range
65.0
44 LChWT
42 LChWT
46 LChWT
60.0
ECWT, F
55.0
50.0
45.0
40.0
35.0
30.0
0
10
20
30
40
50
60
70
80
90
100
110
Percent Load
Min. ECWT = 5.25 + 0.88*(LWT) - DTFL*(PLD/100) + 22*(PLD/100)2
•
•
•
•
ECWT = Entering condenser water temperature
LWT = Leaving chilled water temperature
DTFL = Chilled Water Delta-T at full load
PLD = The percent chiller load point to be checked
For example; at 44°F LWT, 10 degree F Delta-T, and 50% full load operation, the entering
condenser water temperature could be as low as 44.5°F. This provides excellent operation with
water-side economizer systems.
Over 300 Tons
Chillers over 300 tons are equipped with thermal expansion valves (TXV) and will start and run
with entering condenser water temperatures as low as calculated by the following equation and
shown in the chart following.
Min. ECWT = 7.25 + LWT– 1.25* DTFL(PLD/100) + 22*(PLD/100) 2
• ECWT = Entering condenser water temperature
• LWT = Leaving chilled water temperature
• DTFL = Chilled Water Delta-T at full load
• PLD = The percent chiller load point to be checked
Catalog WSC/WDC-4
51
Figure 14, Minimum Entering Condenser Water Temperature (TXV)
Minimum Entering Condenser Water Temperature - 10 F Range
65.0
44 LChWT
42 LChWT
46 LChWT
60.0
ECWT, F
55.0
50.0
45.0
40.0
35.0
30.0
0
10
20
30
40
50
60
70
80
90
100
110
Percent Load
For example; at 44°F LWT, 10 degree F Delta-T, and 50% full load operation, the entering
condenser water temperature could be as low as 50.5°F. This provides excellent operation with
water-side economizer systems.
Depending on local climatic conditions, using the lowest possible entering condenser water
temperature may be more costly in total system power consumed than the expected savings in
chiller power would suggest, due to the excessive fan power required.
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 total peak load chiller power. McQuay’s Energy Analyzer program can optimize
the chiller/tower operation for specific buildings in specific locales.
Even with tower fan control, some form of water flow control, such as tower bypass, is
recommended.
Figure 15 illustrates two temperature actuated tower bypass arrangements. The “Cold Weather”
scheme provides better startup under cold ambient air temperature conditions. The check valve
may be required to prevent entraining air at the pump inlet.
Figure 15, Bypass, Mild Weather Operation
52
Bypass, Cold Weather Operation
Catalog WSC/WDC-4
Mixing Single and Dual Compressor Chillers
Dual compressor chillers excel at part load operation, while single compressor chillers usually
have better full load efficiency. A good chiller plant strategy is to install one dual and one or more
single compressor units. Run the dual until it is fully loaded, then switch to the single compressor
unit and run it only at full load, using the dual to trim the load.
Series Counterflow and Series Parallel Chillers
The design of piping systems can greatly impact chiller performance. A popular system is to place
the evaporators in series with the chilled water flowing from one evaporator to the next as shown
in Figure 16 and Figure 17. Two different condenser water piping arrangements can be used.
Parallel flow (Figure 16) divides the total condenser flow between the two condensers. The
counterflow system (Figure 17) puts all of the condenser water through the condenser of the lag
chiller (chiller producing the coldest evaporator leaving water) and then through the lead chiller
(chiller seeing the warmest evaporator water temperatures).
For the evaporator design, it is a good design philosophy to use two identical machines. Since the
lead machine will see the warmest evaporator water, the lead machine will have the greater
capacity and larger portion of the total system evaporator temperature drop. Again referring to
Figure 16 and Figure 17, the lead machine has an 8.4 degree drop (56.0°F-47.6°F) and the lag
machine has a 5.6 degree drop (47.6°F – 42.0°F).
Condenser water flow is important to overall system efficiency. With parallel flow (Figure 16),
the condensers have identical flow conditions (95 to 85 degrees in this example) with the
compressor lift shown. With counterflow arrangement the lift on the lead machine is significantly
lower, reducing compressor work and making the overall system efficiency about 2% better. Even
though the chiller performance is different, it is good practice to use the same chiller models.
Both the WSC and WDC chillers are suitable for series counterflow arrangement and include
controls specifically designed for series chillers. For more information, please refer to
Application guide AG –31-003: Chiller plant design.
Figure 16, Series Parallel Flow
Figure 17, Series Counterflow Flow
Catalog WSC/WDC-4
53
Oil Coolers
McQuay centrifugal chillers, sizes 063 through 126, have a factory-mounted, water-cooled oil
cooler with a temperature controlled water regulating valve and solenoid valve for each
compressor. Cooling water connections are located at the rear of the unit, near the compressor
and are shown on the specific unit certified drawings. Models WDC 063 through 087 have the
cooling water connections in the lower portion of one tube sheet. Models WSC and WDC 050
chillers have refrigerant-cooled oil coolers and do not require a cooling water connection.
WDC 063, 079, 087, 100 and 126 dual compressor chillers are equipped as above, but the water
piping for the two oil coolers is factory piped to a common inlet and outlet connection.
Field water piping to the inlet and outlet connections must be installed according to good piping
practices and must include stop valves to isolate the cooler for servicing. A 1" minimum cleanable
filter (40 mesh maximum) and drain valve or plug must also be field installed. The water supply
for the oil cooler must be from the chilled water circuit, or from an independent clean source such
as city water. When using chilled water, it is important that the water pressure drop across the
evaporator is greater than the pressure drop across the oil cooler or insufficient oil cooler flow
will result. If the pressure drop across the evaporator is less than the oil cooler, the oil cooler
must be piped across the chilled water pump, provided that its pressure drop is sufficient. The
water flow through the oil cooler will be adjusted by the unit's regulating valve so that the
temperature of oil supplied to the compressor bearings (leaving the oil cooler) is between 90°F
and 110°F (32°C and 43°C).
Compressors using chilled water for oil cooling will often start with warm "chilled water" in the
system until the chilled water loop temperature is pulled down. With cooling water in the 40°F to
55°F (4°C to 13°C) range, considerably less water will be used and the pressure drop will be
greatly reduced. The following table contains oil cooler data at various inlet water temperatures.
Table 7, Oil Cooler Performance
Hot Side
POE Lub
Cold Side
Water
Cold Side
Water
Cold Side
Water
Cold Side
Water
1.54
WSC 063 - 087
Flow, gpm
9.9
11.9
2.9
2.0
Inlet Temperature, °F
118.0
80.0
65.0
55.0
45.0
Outlet Temperature, °F
100.0
87.3
94.5
98.3
101.4
-
4.3
0.3
0.14
0.09
Flow, gpm
15.8
21.9
5.11
3.5
2.7
Inlet Temperature, °F
120.0
80.0
65.0
55.0
45.0
Outlet Temperature, °F
100.0
87.0
95.0
99.0
102.3
-
3.78
0.23
0.11
0.07
Pressure Drop, psi
WSC 100 - 126
Pressure Drop, psi
NOTES:
1.
2.
Data is for a single compressor (oil cooler). Double the flow rates shown for WDC dual compressor chillers.
Pressure drop includes the oil cooler and control valve.
When supplied with city water, the oil piping must discharge through a trap into an open drain to
prevent draining the cooler by siphoning. The city water can also be used for cooling tower
makeup by discharging it into the tower sump from a point above the highest possible water level.
NOTE: Particular attention must be paid to chillers with variable chilled water flow through the
evaporator. The pressure drop available at low flow rates can very well be insufficient to supply
the oil cooler with enough water. In this case an auxiliary booster pump can be used or city water
employed.
54
Catalog WSC/WDC-4
Cooling Water Connection Sizes: WDC 100/126 have 1 1/2 in. FPT connections, all other WDC
and WSCs are 1 in. FPT.
Figure 18, Oil Cooler Piping Across Chilled Water Pump
PUMP
CHILLER
R
S
OIL COOLER
STOP
VALUE
SOLENOID
VALVE
STOP
VALVE
STRAINER
MAX. 40 MESH
DRAIN VALVE
OR PLUG
Figure 19, Oil Cooler Piping With City Water
R
OIL COOLER
S
SOLENOID
VALVE
WATER
SUPPLY
COOLING TOWER
STOP
VALVE
STRAINER
MAX. 40
MESH
DRAIN VALVE
OR PLUG
COOLING TOWER MAKEUP
DISCHARGE ABOVE
HIGHEST POSSIBLE
WATER LEVEL
OPEN
DRAIN
Pumps
Model WSC and WDC chiller compressor motors operate at 3600 rpm on 60 Hz power (3000 rpm
on 50 Hz). When VFDs are employed, the hertz/speed can be reduced by 70%. To avoid the
possibility of objectionable harmonics in the system piping, 4-pole, 1800/1500 rpm system pumps
should be used. The condenser water pump(s) must be cycled off when the last chiller of the
system cycles off. This will keep cold condenser water from migrating refrigerant to the
condenser. Cold liquid refrigerant in the condenser can make start-up difficult. In addition,
turning off the condenser water pump(s) when the chillers are not operating will conserve energy.
Piping
Piping must be adequately supported to remove weight and strain on the chiller’s fittings and
connections. Be sure piping is adequately insulated. Install a cleanable 20-mesh water strainer
upstream of the evaporator and condenser. Install enough shutoff valves to permit draining water
from the evaporator or condenser without draining the complete system.
CAUTION
Freeze Notice: The evaporator and condenser are not self-draining. Both must be
blown out to completely remove water to help prevent freezup.
Include thermometers and pressure gauges at the chiller inlet and outlet connections and air vents
at the high points of piping. The water heads can be interchanged (end for end), allowing water
connections to be made at either end of the unit. Use new head gaskets when interchanging water
heads. When water pump noise is objectionable, use rubber isolation sections at both the inlet and
Catalog WSC/WDC-4
55
outlet of the pump. Vibration eliminator sections in the condenser inlet and outlet water lines are
not normally required. Where noise and vibration are critical and the unit is mounted on spring
isolators, flexible piping and conduit connections are necessary. If not factory installed, a flow
switch or pressure differential switch must be installed in the leaving chilled water line in
accordance with the flow switch manufacturer’s instructions.
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.
A water treatment service should be used. McQuay International is not responsible for damage or
faulty operation from untreated or improperly treated water.
Machine Room Ventilation
In the market today, centrifugal chillers are available with either hermetic or open type motors.
Hermetic motors are cooled with refrigerant and dissipate their heat through the cooling tower.
On the other hand, open motors circulate equipment room air across themselves for cooling and
reject the heat to the equipment room. McQuay chillers have hermetic motors and DO NOT
require additional ventilation.
For chillers with open-drive type, air-cooled motors, good engineering practice dictates that the
motor heat be removed to prevent high equipment room temperatures. In many applications this
requires a large volume of ventilation air, or mechanical cooling to properly remove this motor
heat.
EXAMPLE: 1000 tons x 0.6 kW/Ton x 0.04 motor heat loss x 0.284 Tons/kW = 7 tons (24 kW) cooling
The energy and installation costs of ventilation or mechanical cooling equipment must be
considered when evaluating various chillers. For a fair comparison, the kW used for the
ventilation fans, or if mechanical cooling is required, the additional cooling and fan energy must
be added to the open motor compressor energy when comparing hermetic drives. Additionally,
significant costs occur for the purchase, installation, and maintenance of the ventilation or air
handling units.
Equipment room ventilation and safety requirements for various refrigerants is a complex subject
and is updated from time to time. The latest edition of ASHRAE 15 should be consulted.
Thermal Storage
McQuay chillers are designed for use in thermal storage systems. The chillers have two operating
conditions that must be considered. The first is normal air-conditioning duty where leaving
evaporator fluid temperatures range from 40°F to 45°F (4.4°C to 7.2°C). The second condition
occurs during the ice making process when leaving fluid temperatures are in the 22°F to 26°F
(-5.6°C to -3.3°C) range.
The MicroTech II control system will accommodate both operating points. The ice mode can be
started or stopped by an input signal to the microprocessor from a BAS or through a chilled water
reset signal. When a signal is received to change from the ice mode to the normal operating mode,
the chiller will shut down until the system fluid temperature rises to the higher setpoint. The
chiller will then restart and continue operation at the higher leaving fluid temperature. When
changing from normal cooling to the ice mode, the chiller will load to maximum capacity until the
lower setpoint is reached.
Computer selections must be made to check that the chiller will operate at both conditions. If the
“ice mode” is at night, the pressure differentials between the evaporator and condenser are usually
similar to normal cooling applications. The leaving fluid temperature is lower, but the condensing
temperature is also lower because the cooling tower water is colder. If the ice mode can also
56
Catalog WSC/WDC-4
operate during the day, when cooling tower water temperatures are high, a proper selection
becomes more difficult because the two refrigerant pressure differentials are significantly
different.
A three-way condenser water control valve is always required.
Variable Speed Pumping
Variable speed pumping involves changing system water flow relative to cooling load changes.
McQuay centrifugal chillers are designed for this duty with two limitations.
First, the rate of change in the water flow needs to be slow, not greater than 10% of the change per
minute. The chiller needs time to sense a load change and respond.
Second, the water velocity in the vessels must be 3 to 10 fps (0.91 and 3.0 m/sec). Below 3 fps
(0.91 m/sec), laminar flow occurs which reduces heat transfer. Above 10 fps (3.0 m/sec),
excessively high pressure drops and tube erosion occur. These flow limits can be determined from
the McQuay selection program.
We recommend variable flow only in the evaporator because there is virtually no change in chiller
efficiency compared to constant flow. In other words, there is no chiller energy penalty. Although
variable speed pumping can be done in the condenser loop, it is usually unwise. The intent of
variable flow is to reduce pump horsepower. However, reducing condenser water flow increases
the chiller’s condensing pressure, increasing the lift that the compressor must overcome which, in
turn, increases the compressor’s energy use. Consequently, pump energy savings can be lost
because the chiller operating power is significantly increased.
Low condenser flow can cause premature tube fouling and subsequent increased compressor
power consumption. Increased cleaning and/or chemical use can also result.
Vibration Mounting
Every McQuay chiller is run tested and compressor vibration is measured and limited to a
maximum rate of 0.14 inches per second, which is considerably more stringent than other
available compressors. Consequently, floor-mounted spring isolators are not usually required.
Rubber mounting pads are shipped with each unit. It is wise to continue to use piping flexible
connectors to reduce sound transmitted into the pipe and to allow for expansion and contraction.
Operating/Standby Limits
Equipment room operating temperature (check factory for VFD applications): 32°F to 104°F.
Equipment room standby temperature: 32°F to 122°F.
Maximum entering condenser water temperature, startup: design plus 5 degrees F.
Maximum oil cooler/VFD entering water temperature: 90°F.
Minimum leaving chilled water temperature without anti-freeze: 38°F.
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, and loss of
temperature control.
For normal comfort cooling applications where the cooling load changes relatively slowly, we
recommend a minimum system volume of three minutes times the flow rate (gpm). For example,
if the design chiller flow rate is 1000 gpm, we recommend a minimum system volume of 3000
gallons (1000 gpm x 3 minutes).
For process applications where the cooling load can change rapidly, additional system water
volume is needed. A process example would be a quench tank where the load would be stable
Catalog WSC/WDC-4
57
until the hot material is dipped into the water tank. Then, the load would increase drastically.
Large storage capacity will usually be required for this type of application.
System volume = {1000 gpm x 3 minutes} + {(5 increment of 10% increase) x (3 minutes) x 1000
gpm} = 18,000 gallons
Since there are many other factors that can influence performance, systems can successfully
operate below these suggestions. However, as the water volume decreases below these
suggestions, the possibility of problems increases. We believe that these guidelines should be an
industry standard and not just recommendations from McQuay.
Relief Valves
Vessel Relief Valves
Figure 20, Typical Vent Piping
Relief valve connection sizes are 1-inch FPT and are in
the quantity shown in Table 10 and Table 11 for the
evaporator and condenser. In addition, there is a relief
valve (3/8 inch flare) on the top of the oil sump of all
units except variants of the 050 compressor, which
have the valve mounted on the motor end of the
compressor.
All relief valves must be piped to the outside of the
building in accordance with ANSI/ASHRAE 15-2001.
The new 2001 standard has revised the calculation
method compared to previous issues.
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 or replacement,
leaving the other in operation. Only one of the two
valves is in operation at any time. Where 4 valves are
shown, on some large vessels, they consist of two
relief valves mounted on each of two transfer valves.
Only two relief valves of the four are active at any
time.
Vent piping is sized for only one valve of the set since only one can be in operation at a time.
Relief Pipe Sizing (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 HFC-134a vessels is calculated as
follows:
Inch-Pound Units
SI Units
L=
(
0.215d 5 PO2 − P22
fC r2
)− d
* ln
(PO / P2 )
6f
L=
(
7.4381 x 10 −15 d 5 PO2 − P22
fC r2
)− d
*ln
(PO / P2 )
500 f
Where
L = equivalent length of discharge piping
Rr = rated capacity as stamped on the relief valve in lb/min (kg/s)
f = Moody friction factor in fully turbulent flow. Typical values given in
Table 8, Moody friction factor (f)
Piping NPS
1
2
3
4
58
DN
25
50
80
100
ID (in.)
1.049
2.067
3.068
4.026
f
0.0225
0.0190
0.0173
0.0163
Catalog WSC/WDC-4
d = inside diameter of pipe
ln = natural logarithm
P2 = absolute pressure at outlet of discharge piping, psi (kPa)
Po = allowed back pressure (absolute) at the outlet of the relief valve. psi (kPa), 15% of set
pressure,
Po = (0.15P) + atmospheric pressure
McQuay centrifugal chillers have the following relief valve settings and discharge capacity:
WSC evaporator and condenser = 200 psi, 75.5 lb of air/min
WDC evaporator = 180 psi, 68.5 lb of air/min
WDC condenser = 225 psi, 84.4 lb of air/min
Since the pressures and valve size are fixed for McQuay chillers, the above equation can be
reduced to the simple table shown below.
Table 9, Relief Valve Piping Sizes
Pipe Size inch (NPT)
1 1/4
1 1/2
2
2 1/2
3
4
Moody Factor
Equivalent length (ft)
0.0209
2.2
0.0202
18.5
0.0190
105.8
0.0182
296.7
0.0173
973.6
0.0163
4117.4
NOTE: A 1-inch pipe is too small to handle these valves. A pipe increaser must be installed at the valve outlet.
Per ASHRAE Standard 15, the pipe size cannot be less than the relief device. The discharge from
more than one relief valve can be run into a common header, the area of which shall not be less
than the sum of the areas of the connected pipes. For further details, refer to ASHRAE Standard
15. The common header can be calculated by the formula:
DCommon = §¨ D12 + D22 ....D n2 ·¸
©
¹
0.5
The above information is a guide only. Consult local codes and/or latest version of ASHRAE
Standard 15 for sizing data.
Standby Power
The McQuay dual compressor chillers have a considerable advantage over the same capacity
single compressor chillers when it comes to installations incorporating engine-driven standby
generators for emergency power. Starting with only one compressor greatly reduces the load on
the power plant and can reduce its size, saving considerable plant first cost.
It is essential that any centrifugal chiller connected to standby power come to a complete stop and
then be restarted with the standby power. Attempting to switch from regular line power to
auxiliary power while the compressor is running can result in extreme transient torque that will
severely damage the compressor.
Electrical Data
Wiring and Conduit
Wire sizes must comply with local and state electrical codes. Where total amperes require larger
conductors than a single conduit would permit, limited by dimensions of motor terminal box, two or
more conduits can be used. Where multiple conduits are used, all three phases must be balanced in
each conduit. Failure to balance each conduit will result in excessive heating of the conductors and
unbalanced voltage.
An interposing relay can be required on remote mounted starter applications when the length of the
conductors run between the chiller and starter is excessive.
Note: On WDC dual compressor units, dual power leads are standard, requiring separate power leads
properly sized and protected to each compressor starter or VFD. Separate disconnects must be used.
Catalog WSC/WDC-4
59
NOTES for Following Wiring Diagram
1. Compressor motor starters are either factory mounted and wired, or shipped separate for field
mounting and wiring. If provided by others, starters must comply with McQuay specification
359AB99. All line and load side power conductors must be copper.
2. If starters are freestanding, then field wiring between the starter and the control panel is required.
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. Main power wiring between starter and motor terminal is factory-installed
when units are supplied with unit-mounted starters. Wiring of free-standing starter must be wired
in accordance with NEC and connection to compressor motor terminals must be made with
copper wire and copper lugs only.
3. For optional sensor wiring, see unit control diagram. It is recommended that dc wires be run
separately from 115 Vac wiring.
4. Customer furnished 24 or 120 Vac power for alarm relay coil can be connected between UTB1
terminals 84 power and 51 neutral of the control panel. For normally open contacts, wire
between 82 & 81. For normally closed contacts, wire between 83 & 81. The alarm is operator
programmable. The maximum rating of the alarm relay coil is 25 VA.
5. Remote on/off control of unit can be accomplished by installing a set of dry contacts between
terminals 70 and 54.
6. Evaporator and condenser flow switches are required and must be wired as shown. WDC dual
compressor units require DPDT switches. If field supplied pressure differential switches are
used then these must be installed across the vessel and not the pump.
7. 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 (UTBI) 85 power / 86 neutral,
PE equipment ground.
8. Optional customer supplied 115 Vac, 25 VA maximum coil rated chilled water pump relay (EP 1 &
2) can be wired as shown. This option will cycle the chilled water pump in response to building
load.
9. 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.
10. Optional customer supplied 115 Vac, 25 VA maximum coil rated cooling tower fan relays (CL C4) can be wired as shown. This option will cycle the cooling tower fans in order to maintain unit
head pressure.
11. Auxiliary 24 Vac rated contacts in both the chilled water and condenser water pump starters must
be wired as shown.
12. For VFD, Wye-Delta, and solid state starters connected to six (6) terminal motors. The
conductors between the starter and motor carry phase current and selection shall be based on
58 percent of the motor rated load amperes (RLA). Wiring of free-standing starter must be in
accordance with the NEC and connection to the compressor motor terminals shall be made with
copper wire and copper lugs only. Main power wiring between the starter and motor terminals is
factory-installed when chillers are supplied with unit-mounted starters.
13. Optional Protocol Selectability BAS interfaces. The locations and interconnection requirements
for the various standard protocols are found in their respective installation manuals, obtainable
from the local McQuay sales office and also shipped with each unit:
Modbus IM 743-0
LonWorks IM 735-0
BACnet IM 736-0
14. The “Full Metering” or “Amps Only Metering” option will require some field wiring when freestanding starters are used. Wiring will depend on chiller and starter type. Consult the local
McQuay sales office for information on specific selections.
60
Catalog WSC/WDC-4
Figure 21, Typical Field Connection Diagram, WSC Unit
MICROTECH CONTROL
BOX TERMINALS
(115V)
GND
(24V)
PE
54
85
POWER
* NOTE 7
86
NEUTRAL
* NOTE 10
* COOLING
TOWER
FOURTH
STAGE
STARTER
55
O
C4
74
H
A
O
86
* NOTE 10
O
A
EP2
86
C
79
H
* COOLING
TOWER
THIRD
STAGE
STARTER
70
80
H
C3
73
H
A
O
EP1
78
A
C
77
* NOTE 10
76
H
* COOLING
TOWER
SECONDH
STAGE
STARTER
O
C2
75
A
H
O
* NOTE 10
O
A
CP2
H
* COOLING
TOWER
FIRST
STAGE
STARTER
C
T3-S
C1
A
EF
CF
81
COMMON
82(NO)
A
83(NC)
ALARM RELAY
(NOTE 4)
84
POWER
H
52
O
COOLING TOWER
BYPASS VALVE
71
1-10 VDC
CP1
A
C
71
1-10 VDC
COOLING TOWER VFD
L1
L2
53
MICROTECH
COMPRESSOR CONTROL
BOX TERMINALS
CTB1
L3
NOTE 2
(NOTE 1)
-LOAD-
U
V
W
115 VAC
T1
GND
COMPRESSOR
MOTOR
STARTER
STARTER LOAD SIDE TERMINBALS
VFD
PE
CP1
L1
CP2
L2
23(5A)
23
24(5)
24
25
25
1
1
T6
T2
T4
T3
T5
COMPRESSOR TERMINALS
STARTER LOAD SIDE TERMINBALS
WYE-DELTA
T1
T2
T3
T1
T2
T3
T4
T5
T6
T4
T5
T6
2
2
3
4
4
6
11
11
11
12
12
22
22
NOTE 2
LESS
THAN
30V
OR
24VAC
- FOR DETAILS OF CONTROL REFER
TO UNIT CONTROL SCHEMATIC
330342101
- COMPRESSOR CONTROL
SCHEMATIC 330342201
- LEGEND: 330343001
COMPRESSOR TERMINALS
3
- FOR DC VOLTAGE AND 4-20 MA
CONNECTIONS (SEE NOTE 3)
STARTER LOAD SIDE TERMINBALS
SOLID STATE
T1
T1
T2
T6
T2
* FIELD SUPPLIED ITEM
NOTE 12
T3
T4
T3
T5
COMPRESSOR TERMINALS
STARTER LOAD SIDE TERMINBALS
MEDIUM AND HIGH VOLTAGE
T1
T2
T3
T1
T2
T3
COMPRESSOR TERMINALS
330387901-0A
See notes on preceding page.
Catalog WSC/WDC-4
61
Control Power
The 115-volt control power can be supplied from the starter or a transformer (meeting the
requirements of McQuay Specification 359A999) separate from the starter. Either source must be
properly fused with 20-amp dual element fuses or with a circuit breaker selected for motor duty.
If the control transformer or other power source for the control panel is remote from the unit,
conductors must be sized for a maximum voltage drop of 3%. Required circuit ampacity is 20
amps at 115 volts. Conductor size for long runs between the control panel and power source,
based upon National Electrical Code limitations for 3% voltage drop, can be determined from the
table below.
Control Power Line Sizing
Maximum Length, ft (m)
Wire Size (AWG)
Maximum Length, ft (m)
0 (0) to 50 (15.2)
12
120 (36.6) to 200 (61.0)
Wire Size (AWG)
6
50 (15.2) to 75 (22.9)
10
200 (61.0) to 275 (83.8)
4
75 (22.9) to 120 (36.6)
8
275 (83.8) to 350 (106.7)
3
Notes:
1.
Maximum length is the distance a conductor will traverse between the control power source and the unit control panel.
2.
Panel terminal connectors will accommodate up to number 10 AWG wire. Larger conductors will require an intermediate
junction box.
62
Catalog WSC/WDC-4
Chiller Identification
To provide a wide range of components to match job requirements of capacity, efficiency and
competitive initial cost, McQuay WSC and WDC centrifugal chillers are selected by computer
and identified by their components.
The variations of compressor, impeller, gear ratio, evaporator and condenser tube surface and
configuration provide over 1,000,000 combinations of standard components within the range of 80
to 2,500 tons. It is impractical to catalog all of these combinations. Therefore, computer selection
for specific application conditions is required. The complete unit model code is then established
as follows:
Figure 22, Chiller Identification
MODEL CODE EXAMPLE:
W S C - 063M - AQ - 18S / E2012- E B- 2 * A / C1812- B L Y Y - 2 * A Y Y Y R / 134
COMPRESSOR
Packaged Water Cooled
Centrifugal Chiller
S = Single Compressor
D = Dual Compressor
Hermetic Compressor Model
Compressor/Impeller Code
Gear Ratio
Motor/Voltage Code
EVAPORATOR
Evaporator Shell Description
[Diameter (in.), Length (ft.)]
Tube Count Code
Tube Type Code
Number of Passes (1, 2, 3)
Water Inlet Location (R = Right Inlet; L = Left Inlet)
Connection Type
Condenser Shell Description [Diameter (in.), Length (ft.)]
Tube Count Code
Type Type Code
CONDENSER
Tube Count Code (Heat Recovery Condenser)
Tube Type Code (Heat Recovery Conderser)
Number of Passes (1, 2, 3)
Water Inlet Location (R = Right Inlet; L = Left Inlet)
Connection Type
Number of Passes (Heat Recovery Condenser)
Water Inlet Location (Heat Recovery Condenser)
Connection Type (Heat Recovery Condenser)
R
Motor Manufacturer
Refrigeration Type (134 = HFC-134a)
Catalog WSC/WDC-4
63
Physical Data and Weights
Evaporator
The optional insulation of cold surfaces includes the evaporator and non-connection water head,
suction piping, compressor inlet, motor housing, and motor coolant suction line.
The insulation used is UL recognized (File # E55475). It is 3/4" thick ABS/PVC flexible foam
with skin having a K factor of 0.28 at 75°F. The 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 appropriate requirements 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
Refrigerant side design pressure is 200 psi (1380 kPa) on WSC units. WDC evaporators are 180
psi (1242 kPa) and WDC condensers are 225 psi (1552 kPa). Standard water-side design pressure
is 150 psi (1034 kPa) on all vessels. 300 psi (2068 kPa) is available as an option.
In the event insulation is to be field installed, the approximate total square footage of insulation
surface required for individual packaged chillers is tabulated by evaporator code and can be found
below.
Table 10, Evaporator Physical Data
Evaporator
Code
WSC
WDC
Water
Volume
gal (L)
23 (87)
27 (103)
31 (117)
37 (139)
38 (145)
45 (170)
63 (240)
79 (301)
88 (335)
110 (415)
61 (231)
72 (273)
101 (381)
126 (478)
74 (281)
89 (336)
157 (594)
128 (484)
152 (574)
243 (918)
222 (841)
347 (1313)
481 (1819)
327 (1237)
556 (2106)
661 (2503)
Insulation
Area
sq ft (m2)
75 (7.0)
78 (7.2)
82 (7.6)
84 (7.8)
66 (6.1)
90 (8.3)
90 (8.3)
144 (13.4)
131 (12.1)
157 (14.6)
76 (7.1)
102 (9.4)
102 (9.4)
162 (15.0)
86 (8.0)
115 (10.6)
207 (19.2)
155 14.4)
129 (11.9)
239 (22.2)
148 (13.7)
264 (24.5)
330 (30.6)
169 (15.6)
302 (281)
377 (35.0)
Vessel Dry
Weight
lb (kg)
2237 (1013)
2504 (1134)
2543 (1152)
2862 (1296)
2708 (1227)
3071 (1391)
3550 (1609)
4200 (1903)
4410 (1999)
5170 (2343)
3381 (1532)
3880 (1758)
4745 (2150)
5645 (2558)
4397 (1992)
5075 (2299)
7085 (3211)
5882 (2665)
6840 (3099)
9600 (4351)
8922 (4042)
12215 (5536)
15045 (6819)
11125 (5040)
16377 (7429)
17190 (7791)
Number
of Relief
Valves
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
1
1
2
1
2
2
2
2
2
Add for
MWB
lb (kg)
338 (153)
338 (153)
478 (217)
478 (217)
600 (272)
600 (272)
600 (272)
600 (272)
700 (317)
700 (317)
899 (407)
899 (407
899 (407
899 (407
1386 (628)
1386 (628)
1386 (628)
2115 (958)
2115 (958)
2115 (958)
2836 (1285)
2836 (1285)
2836 (1285)
4578 (2074)
4578 (2074)
4578 (2074)
E1809
X
E1812
X
E2009
X
E2012
X
E2209
X
E2212
X
E2212
X
E2216
X
E2412
X
E2416
X
E2609
X
E2612
X
E2612
X
E2616
X
E3009
X
E3012
X
E3016
X
E3609
X
E3612
X
E3616
X
E4212
X
E4216
X
E4220
X
E4812
X
E4816
X
E4820
X
Notes:
1. Water capacity is based on standard tube configuration and standard heads.
2. Vessel weight includes the shell, maximum tubes, and standard heads, no refrigerant.
3. MWB, marine water box, weight add is the water box weight minus a standard dished head weight.
64
MWB Cover
Only, Weight
lb (kg)
99 (45)
99 (45)
148 (67)
148 (67)
175 (79)
175 (79)
175 (79)
175 (79)
240 (109)
240 (109)
302 (137)
302 (137)
302 (137)
302 (137)
517 (234)
517 (234)
517 (234)
805 (365)
805 (365)
805 (365)
1181 (535)
1181 (535)
1181 (535)
1837 (832)
1837 (832)
1837 (832)
Catalog WSC/WDC-4
Condenser
With positive pressure systems, the pressure variance with temperature is always predictable, and
the vessel design and relief protection are based upon pure refrigerant characteristics. Negative
pressure systems are not ASME designed, inspected and stamped. R-134a requires ASME vessel
design, inspection and testing and uses spring-loaded pressure relief valves. Negative pressure
units use rupture disks. When an over pressure condition occurs, the rupture disk is permanently
destroyed. Spring-loaded relief valves purge only the amount of refrigerant required to reduce the
system pressure to the valve setting level and then close.
Refrigerant side design pressure is 200 psi (1380 kPa) on WSC units and 225 psi (1552 kPa) on
WDC units. Standard water side design pressure is 150 psi (1034 kPa) on all vessels. 300 psi
(2068 kPa) is available as an option.
Pumpdown
To facilitate compressor service, all McQuay centrifugal chillers are designed to permit
pumpdown and isolation of the entire refrigerant charge in the unit’s condenser. Dual compressor
units, and single compressor units equipped with the optional suction shutoff valve, can also be
pumped down into the evaporator. No separate pumpout receiver is required on most
installations.
Table 11, Condenser Physical Data
Condenser
Code
WSC
WDC
Pumpdown
Capacity
lb (kg)
Water
Volume
gal (L)
Vessel Dry
Weight
lb (kg)
Number
of Relief
Valves
Add for
MWB
lb (kg)
C1609
X
468 (213)
24 (92)
1589 (718)
2
283 (128)
C1612
X
677 (307)
33 (123)
1870 (847)
2
283 (128)
C1809
X
597 (271)
34 (128)
1835 (831)
2
402 (182)
C1812
X
845 (384)
44 (166)
2183 (989)
2
402 (182)
C2009
X
728 (330)
47 (147)
2230 (1010)
2
478 (216)
C2012
X
971 (440)
62 (236)
2677 (1213)
2
478 (216)
C2209
X
822 (372)
60 (228)
2511 (1137)
2
478 (216)
C2212
X
1183 (537)
76 (290)
3031 (1373)
2
478 (216)
C2212
X
1110 (504)
89 (337)
3075 (1395)
2
478 (216)
C2216
X
1489 (676)
114 (430)
3861 (1751)
2
478 (216)
C2416
X
1760 (799)
143 (540)
4647 (2188)
2
685 (310)
C2609
X
1242 (563)
89 (335)
3210 (1454)
2
902 (408)
C2612
X
1656 (751)
111 (419)
3900 (1767)
2
902 (408)
C2616
X
2083 (945)
159 (603)
5346 (2425)
2
902 (408)
C3009
X
1611 (731)
114 (433)
4356 (1973)
2
1420 (643)
C3012
X
2148 (975)
144 (545)
5333 (2416)
2
1420 (643)
C3016
X
2789 (1265)
207 (782)
6752 (3063)
4
1420 (643)
C3612
X
2963 (1344)
234 (884)
7508 (3401)
2
2115 (958)
C3616
X
3703 (1725)
331 (1251)
9575 (4343)
4
2115 (958)
C4212
X
3796 (1722)
344 (1302)
10267 (4651)
2
2836 (1285)
C4216
X
5010 (2273)
475 (1797)
12662 (5743)
4
2836 (1285)
C4220
X
5499 (2494)
634 (2401)
17164 (7785)
4
2836 (1285)
C4812
X
4912 (2228)
491 (1855)
13077 (5924)
4
4578 (2074)
C4816
X
5581 (2532)
717 (2715)
18807 (8530)
4
4578 (2074)
C4820
X
7034 (3191)
862 (3265)
23106 (10481)
4
4578 (2074)
Notes:
1. Condenser pumpdown capacity based on 90% full at 90°F.
2. Vessel weight includes the shell, maximum tubes, and standard heads, no refrigerant.
3. MWB, marine water box, weight add is the water box weight minus a standard dished head weight.
MWB Cover
Only,
Weight
lb (kg)
81 (37)
81 (37)
124 (56)
124 (56)
148 (67)
148 (67)
148 (67)
148 (67)
148 (67)
148 (67)
230 (104)
302 (137)
302 (137)
302 (137)
517 (234)
517 (234)
517 (234)
805 (364)
805 (364)
1181 (535)
1181 (535)
1181 (535)
1837 (8320
1837 (8320
1837 (8320
Compressor
Table 12, Compressor Weights
Compressor Size Ÿ
Weight lb (kg) Ÿ
Catalog WSC/WDC-4
048/050
870
(390)
063
3200
(1440)
079
3200
(1440)
087
3200
(1440)
100
6000
(2700)
113
6000
(2700)
126
6000
(2700)
65
Dimensions
Notes: 1. Drawings included in this section are for rough layout purposes only. Detailed certified drawings, as pdf hard copies o
dgm files, are available from the local McQuay sales office. Do not use for final construction drawings.
2. Obtain specific unit certified drawings for detailed dimensions of water, oil cooler, and relief valve connections.
3. Dimensions in inches (mm).
4. See Physical Data and Weights section for component and unit weights.
5. Allow three feet of service access on all four sides, plus allow the length of the tubes, plus two feet on one end, for
tube removal. The last two numbers in the vessel code are the tube length in feet. The NEC may require more than
3 feet clearance in front of control panels or starting equipment depending voltage and layout.
6. The adjustable control interface panel is shipped unmounted from the unit. When mounted, it can be folded back
within the confines of the unit width and height.
Figure 23, WSC 048/WSC 050, 85 to 165 Tons, (300 to 580 kW)
ADJUSTABLE OPERATOR
INTERFACE PANEL
UNIT
CONTROL
BOX
1” FPT VESSEL RELIEF
VALVE CONNECTIONS
FACTORY
MOUNTED
STARTER
(OPTIONAL)
B
0.75” FPT OIL
COOLER CONNECTION
EVAPORATOR
CONDENSER
Y
X
A
D
E
IN
F
OUT
G
OUT
IN
Y
Z
C
C +16”
VESSEL
CODE
EVAP COND
E1809 C1609
E1812 C1612
E2009 C1609
E2012 C1612
E2009 C1809
E2012 C1812
E2209 C2009
E2212 C2012
66
OVERALL
OVERALL WIDTH
CENTER OF GRAVITY
W/O
HEAD CONN HEIGHT
STARTER
BOTH ENDS
A
B
C
X
Y
Z
134
71
42
55
31
17
(3404)
(1803)
(1067)
(1397) (787) (432)
169
71
42
72
30
16
(4293)
(1803)
(1067)
(1829) (762) (406)
134
71
42
55
31
16
(3404)
(1803)
(1067)
(1397) (787) (406)
169
71
42
72
30
16
(4293)
(1803)
(1067)
(1829) (762) (406)
134
71
42
55
31
17
(3404)
(1803)
(1067)
(1397) (787) (432)
169
71
42
73
30
17
(4293)
(1803)
(1067)
(1854) (762) (432)
134
71
42
55
30
17
(3404)
(1803)
(1067)
(1397) (762) (432)
169
71
42
73
29
17
(4293)
(1803)
(1067)
(1854) (737) (432)
OVERALL LENGTH
1&3
PASS
A
134
(3404)
169
(4293)
134
(3404)
169
(4293)
134
(3404)
169
(4293)
134
(3404)
169
(4293)
2
PASS
A
128
(3251)
163
(4140)
128
(3251)
163
(4140)
128
(3251)
163
(4140)
129
(3277)
164
(4166)
CONNECTIONS
FOOTPRRINT
D
113
(2870)
148
(3759)
113
(2870)
148
(3759)
113
(2870)
148
(3759)
113
(2870)
148
(3759)
E
111
(2819)
145
(3683)
111
(2819)
145
(3683)
111
(2819)
145
(3683)
111
(2819)
145
(3683)
F
42
(1067)
42
(1067)
42
(1067)
42
(1067)
42
(1067)
42
(1067)
42
(1067)
42
(1067)
G
34
(864)
34
(864)
34
(864)
34
(864)
34
(864)
34
(864)
34
(864)
34
(864)
EVAP
2
PASS
COND
2
PASS
6
5
6
5
6
5
6
5
6
6
6
6
8
6
8
6
Catalog WSC/WDC-4
Figure 24, WSC 063, 160 to 300 Tons (560 to 1050 kW)
ADJUSTABLE OPERATOR
INTERFACE PANEL
UNIT
CONTROL
BOX
1” FPT VESSEL RELIEF
VALVE CONNECTIONS
FACTORY
MOUNTED
STARTER
(OPTIONAL)
B
0.75” FPT OIL
COOLER CONNECTION
EVAPORATOR
CONDENSER
Y
X
A
D
E
OUT
IN
F
G
OUT
IN
Y
Z
C
C +17”
VESSEL CODE
EVAP
COND
E2009 C1809
E2012 C1812
E2209 C2009
E2212 C2012
E2209 C2209
E2212 C2212
E2609 C2209
E2612 C2212
E2609 C2609
E2612 C2612
E3012 C2612
E3009 C2609
OVERALL LENGTH
1&3
PASS
2
PASS
HEAD CONN.
BOTH ENDS
CONNECTIONS
OVERALL
OVERALL
WIDTH W/O CENTER OF GRAVITY
HEIGHT
STARTER
FOOTPRINT
A
A
A
B
C
X
Y
Z
D
E
F
G
134
(3404)
169
(4293)
134
(3404)
169
(4293)
134
(3404)
169
(4293)
134
(3404)
169
(4293)
134
(3404)
169
(4293)
175
(4445)
140
(3556)
128
(3251)
163
(4140)
129
(3277)
164
(4166)
129
(3277)
164
(4166)
129
(3277)
164
(4166)
129
(3277)
164
(4166)
167
(4242)
132
(3353)
134
(3404)
169
(4293)
134
(3404)
169
(4293)
134
(3404)
169
(4293)
134
(3404)
169
(4293)
134
(3404)
169
(4293)
175
(4445)
140
(3556)
76
(1930)
76
(1930)
76
(1930)
76
(1930)
76
(1930)
76
(1930)
80
(2032)
80
(2032)
86
(2184)
86
(2184)
90
(2286)
91
(2235)
42
(1067)
42
(1067)
42
(1067)
42
(1067)
42
(1067)
42
(1067)
46
(1168)
46
(1168)
48
(1219)
48
(1219)
53
(1346)
52
(1321)
50
(1270)
68
(1727)
50
(1270)
68
(1727)
51
(1295)
68
(1727)
51
(1295)
69
(1753)
51
(1295)
69
(1753)
67
(1702)
52
(1321)
37
(940)
36
(914)
36
(914)
34
(864)
35
(889)
34
(864)
37
(940)
35
(889)
40
(1016)
38
(965)
41
(1041)
41
(1041)
16
(406)
17
(432)
17
(432)
17
(432)
17
(432)
17
(432)
20
(508)
20
(508)
20
(508)
21
(533)
21
(533)
25
(635)
113
(2870)
148
(3759)
113
(2870)
148
(3759)
113
(2870)
148
(3759)
113
(2870)
148
(3759)
113
(2870)
148
(3759)
148
(3759)
113
(2870)
111
(2819)
145
(3683)
111
(2819)
145
(3683)
111
(2819)
145
(3683)
111
(2819)
145
(3683)
111
(2819)
145
(3683)
145
(3683)
111
(2819)
42
(1067)
42
(1067)
42
(1067)
42
(1067)
42
(1067)
42
(1067)
46
(1168)
46
(1168)
48
(1219)
48
(1219)
53
(1646)
56
(1422)
34
(864)
34
(864)
34
(864)
34
(864)
34
(864)
34
(864)
38
(965)
38
(965)
40
(1016)
40
(1016)
45
(1143)
48
(1219)
EVAP
2
PASS
COND
2
PASS
6
6
6
6
8
6
8
6
8
8
8
8
8
8
8
8
8
8
8
8
10
8
10
8
Note: See notes on page 66.
Catalog WSC/WDC-4
67
Figure 25, WSC 079/087, 300 to 600 Tons (1050 to 2110 kW)
ADJUSTABLE OPERATOR
INTERFACE PANEL
UNIT
CONTROL
BOX
1” FPT VESSEL RELIEF
VALVE CONNECTIONS
FACTORY
MOUNTED
STARTER
(OPTIONAL)
B
EVAPORATOR
0.75” FPT OIL
COOLER CONNECTION
CONDENSER
Y
X
A
D
E
OUT
IN
F
G
OUT
IN
Y
Z
C
C +17”
VESSEL CODE
EVAP
COND
E2209 C2209
E2212 C2212
E2609 C2209
E2612 C2212
E2609 C2609
E2612 C2612
E3009 C2609
E3009 C3009
E3012 C2612
E3012 C3012
E3609 C3009
E3612 C3012
E3612 C3612
“A” OVERALL LENGTH
1&3
PASS
2
PASS
OVERALL
OVERALL
HEAD CONN. HEIGHT WIDTH W/O
STARTER
BOTH ENDS
CONNECTIONS
CENTER OF GRAVITY
FOOTPRINT
A
A
A
B
C
X
Y
Z
D
E
F
G
134
(3404)
169
(4293)
134
(3404)
169
(4293)
134
(3404)
169
(4293)
140
(3556)
140
(3556)
175
(4445)
175
(4445)
140
(3556)
175
(4445)
175
(4445)
129
(3277)
164
(4166)
129
(3277)
164
(4166)
129
(3277)
164
(4166)
132
(3353)
132
(3353)
167
(4242)
167
(4242)
133
(3378)
168
(4267)
168
(4267)
134
(3404)
169
(4293)
134
(3404)
169
(4293)
134
(3404)
169
(4293)
140
(3556)
140
(3556)
175
(4445)
175
(4445)
140
(3556)
175
(4445)
175
(4445)
74
(1880)
74
(1880)
78
(1981)
78
(1981)
83
(2108)
83
(2108)
88
2235)
93
(2362)
88
(2235)
93
(2362)
94
(2388)
94
(2388)
105
(2667)
45
(1143)
45
(1143)
49
(1245)
49
(1245)
52
(1321)
52
(1321)
56
(1422)
58
(1473)
56
(1422)
58
(1473)
74
(1880)
74
(1880)
80
(2032)
50
(1270)
68
(1727)
51
(1295)
69
(1753)
51
(1295)
69
(1753)
52
(1321)
52
(1321)
69
(1753)
70
(1778)
52
(1321)
70
(1778)
70
(1778)
35
(889)
34
(864)
40
(1016)
35
(889)
37
(940)
38
(965)
41
(1041)
43
(1092)
40
(1016)
41
(1041)
43
(1092)
41
(1041)
46
(1168)
18
(457)
18
(457)
22
(559)
21
(533)
21
(533)
22
(559)
25
(635)
26
(660)
25
(635)
26
(660)
34
(864)
34
(864)
38
(965)
113
(2870)
148
(3759)
113
(2870)
148
(3759)
113
(2870)
148
(3759)
113
(2870)
113
(2870)
148
(3759)
148
(3759)
113
(2870)
148
(3759)
148
(3759)
111
(2819)
145
(3683)
111
(2819)
145
(3683)
111
(2819)
145
(3683)
111
(2819)
111
(2819)
145
(3683)
145
(3683)
111
(2819)
145
(3683)
145
(3683)
45
(1173)
45
(1173)
49
(1245)
49
(1245)
52
(1321)
52
(1321)
56
(1422)
58
(1473)
56
(1422)
58
(1473)
74
(1880)
74
(1879)
80
(2032)
37
(9398)
37
(9398)
41
(1041)
41
(1041)
44
1118)
44
1118)
48
(1219)
50
(1270)
48
(1219)
50
(1270)
66
(1676)
66
(1676)
72
(1829)
EVAP
2
PASS
COND
2
PASS
8
8
8
8
8
8
8
8
8
8
8
8
10
8
10
10
10
8
10
10
12
10
12
10
12
12
Notes:
1. E3612/C3612 combination is available on WSC 087 only.
2. E2209/C2209 and E2212/C2212 available on WSC 079 only.
3. See notes on page 66.
68
Catalog WSC/WDC-4
Figure 26, WSC 100-113-126, 600 to 1300 Tons (2100 to 4550 kW)
ADJUSTABLE OPERATOR
INTERFACE PANEL
UNIT
CONTROL
BOX
1” FPT VESSEL RELIEF
VALVE CONNECTIONS
FACTORY
MOUNTED
STARTER
(OPTIONAL)
B
EVAPORATOR
1” FPT OIL
COOLER CONNECTION
CONDENSER
Y
X
A
D
E
IN
F
OUT
G
OUT
IN
Y
Z
C
C +28”
VESSEL CODE
EVAP
COND
E3012
C3012
E3612
C3012
E3612
C3612
E4212
C3612
E4212
C4212
E4812
C4212
E4812
C4812
OVERALL LENGTH
1&3
PASS
2
PASS
CONNECTIONS
OVERALL
OVERALL
HEAD CONN HEIGHT WIDTH W/O CENTER OF GRAVITY
STARTER
BOTH ENDS
FOOTPRINT
A
A
A
B
C
X
Y
Z
D
E
F
G
175
(4445)
175
(4445)
175
(4445)
175
(4445)
175
(4445)
181
(4597)
181
(4597)
167
(4242)
168
(4267)
168
(4267)
170
(4318)
170
(4318)
175
(4445)
175
(4445)
175
(4445)
175
(4445)
175
(4445)
175
(4445)
175
(4445)
181
(4597)
181
(4597)
97
(2464)
99
(2515)
99
(2515)
99
(2515)
102
(2591)
106
(2692)
106
(2692)
61
(1549)
74
(1880)
80
(2032)
86
(2184)
92
(2337)
98
(2489)
104
(2642)
65
(1651)
68
(1727)
68
(1727)
69
(1753)
69
(1753)
69
(1753)
70
(1778)
47
(1194)
47
(1194)
46
(1168)
45
(1143)
45
(1143)
46
(1168)
46
(1168)
21
(553)
27
(686)
31
(787)
35
(889)
37
(940)
42
1067)
46
(1168)
148
(3759)
148
(3759)
148
(3759)
148
(3759)
148
(3759)
148
(3759)
145
(3683)
145
(3683)
145
(3683)
145
(3683)
145
(3683)
145
(3683)
145
(3683)
145
(3683)
61
(1549)
74
(1880)
80
(2032)
86
(2184)
92
2337)
98
2489)
104
(2642)
53
(1346)
66
(1676)
72
(1829)
78
(1981)
84
(2134)
90
(2286)
96
(2438)
EVAP
2
PASS
COND
2
PASS
10
10
12
10
12
12
14
12
14
14
18
14
18
18
Notes:
1. The optional unit-mounted starter is shipped separate for field mounting, brackets and interconnecting cables are shipped with the unit.
2. E3012/C3012 available on 100 only, E4812/C4812 available on 126 only.
3. See notes on page 66.
Catalog WSC/WDC-4
69
Figure 27, WDC 048/050, 180 to 320 tons (630 to 4620 kW)
ADJUSTABLE OPERATOR
INTERFACE PANEL
UNIT
CONTROL
BOX
1” FPT VESSEL RELIEF
VALVE CONNECTIONS
B
STARTER
(OPTIONAL)
EVAPORATOR
STARTER
(OPTIONAL)
1” FPT OIL COOLER CONNECTION
Y
CONDENSER
X
A
D
OUT
IN
FOOTPRINT
OUT
IN
Y
Z
C
C + 20”
VESSEL CODE
EVAP
COND
E2212
C2212
E2216
C2216
E2412
C2212
E2416
C2216
E2612
C2212
E2616
C2216
OVERALL LENGTH
1&3
2
PASS
PASS
OVERALL
OVERALL
HEAD CONN HEIGHT WIDTH W/O
BOTH ENDS
STARTER
CONNECTIONS
CENTER OF GRAVITY
FOOTPRINT
A
A
A
B
C
X
Y
Z
D
E
F
G
169
(4299)
218
(5544)
169
(4299)
218
(5544)
169
(4299)
218
(5544)
164
(4158)
213
(5404)
165
(4180)
214
(5428)
165
(4180)
214
(5428)
169
(4299)
218
(5544)
169
(4299)
218
(5544)
169
(4299)
218
(5544)
79
(2020)
79
(2020)
85
(2149)
83
(2108)
85
(2149)
85
(2149)
40
(1024)
40
(1024)
44
(1131)
43
(1092)
44
(1131)
44
(1131)
72
(1838)
93
(2367)
73
(1854)
95
(2413)
75
(1918)
97
(2467)
29
(733)
31
(800)
33
(838)
34
(864)
35
(902)
36
(921)
15
(384)
20
(498)
18
(457)
20
(496)
20
(505)
19
(492)
150
(3802)
199
(5050)
150
(3802)
199
(5050)
150
(3802)
199
(5050)
147
(3726
196
(4974)
147
(3726
196
(4974)
147
(3726
196
(4974)
41
(1024)
41
(1024)
45
(1131)
43
(1092)
45
(1131)
45
(1131)
35
(872)
35
(872)
39
(979)
38
(965)
39
(979)
39
(979)
EVAP
2
PASS
COND
2
PASS
8
8
8
8
8
8
8
8
8
8
8
8
Note: See notes on page 66.
70
Catalog WSC/WDC-4
Figure 28, WDC 063, 320 to 600 tons (1120 to 2100 kW)
UNIT
CONTROL
BOX
ADJUSTABLE OPERATOR
INTERFACE PANEL
1” FPT VESSEL RELIEF
VALVE CONNECTIONS
B
STARTER
(OPTIONAL)
EVAPORATOR
STARTER
(OPTIONAL)
1” FPT OIL COOLER CONNECTION
Y
CONDENSER
X
A
D
OUT
IN
FOOTPRINT
OUT
IN
Y
Z
C
C + 15”
VESSEL CODE
OVERALL LENGTH
1&3
EVAP
COND
E2416 C2416
E2416 C2616
E2616 C2416
E2616 C2616
E3016 C3016
E3616 C3016
E3616 C3616
PASS
OVERALL
OVERALL
HEAD CONN HEIGHT WIDTH W/O
STARTER
PASS .BOTH ENDS
2
CONNECTIONS
CENTER OF GRAVITY
FOOTPRINT
A
A
A
B
C
X
Y
Z
D
E
F
G
218
(5544)
218
(5544)
218
(5544)
218
(5544)
221
(5623)
224
(5685)
224
(5685)
214
(5426)
214
(5426)
214
(5426)
214
(5426)
214
(5445)
218
(5518)
218
(5518)
218
(5544)
218
(5544)
218
(5544)
218
(5544)
221
(5623)
224
(5685)
224
(5685)
80
(2032)
80
(2032)
80
(2032)
80
(2032)
90
(2280)
99
(2496)
106
(2686)
58
(1470)
58
(1470)
58
(1470)
58
(1470)
64
(1619)
71
(1808)
75
(1886)
91
(2318)
91
(2324)
91
(2324)
92
(2340)
95
(2410)
36
(911)
35
(895)
36
(911)
35
(899)
40
(1029)
17
(425)
17¼
(438)
16
(419)
17
(435)
21
(537)
(2)
(2)
(2)
(2)
(2)
(2)
199
(5048)
199
(5048)
199
(5048)
199
(5048)
199
(5048)
199
(5048)
199
(5048)
196
(4972)
196
(4972)
196
(4972)
196
(4972)
196
(4972)
196
(4972)
196
(4972)
58
(1470)
58
(1470)
58
(1470)
58
(1470)
64
(1619)
71
(1808)
75
(1886)
50
(1267)
50
(1267)
50
(1267)
50
(1267)
56
(1416)
63
(1605)
67
(1682)
EVAP
2
PASS
COND
2
PASS
8
8
8
8
8
8
8
8
10
10
12
10
12
12
Notes:
1.
Additional starter width for E3616/C3616 and E3616/C3016 is 4 inches rather than the 15 inches show in drawing.
2.
Consult McQuay sales office.
3.
See notes on page 66.
.
Catalog WSC/WDC-4
71
Figure 29, WDC 079 and WDC 087, 600 to 1200 tons (2100 to 4220 kW)
ADJUSTABLE OPERATOR
INTERFACE PANEL
UNIT
CONTROL
BOX
1” FPT VESSEL RELIEF
VALVE CONNECTIONS
B
STARTER
(OPTIONAL)
EVAPORATOR
STARTER
(OPTIONAL)
1” FPT OIL COOLER CONNECTION
Y
CONDENSER
X
A
D
OUT
IN
FOOTPRINT
OUT
IN
Y
Z
C
SEE NOTE 1
VESSEL CODE
EVAP COND
E3016 C3016
E3616 C3016
E3616 C3616
E4216 C4216
OVERALL LENGTH
1&3
2
PASS
PASS
OVERALL
OVERALL
WIDTH W/O
HEIGHT
CENTER OF GRAVITY
BOTH ENDS
STARTER
CONNECTIONS
HEAD CONN
FOOTPRINT
A
A
A
B
C
X
Y
Z
D
E
F
G
221
(5620)
224
(5696)
224
(5698)
224
(5698)
214
(5442)
218
(5531)
218
(5531)
219
(5556)
221
(5620)
224
(5696)
224
(5698)
224
(5698)
94
(2407)
100
(2530)
106
(2686)
100
(2530)
57
(1454)
71
(1808)
74
(1886)
93
(2343)
93
(2369)
94
(2388)
94
(2392)
97
(2458)
44
(1127)
45
(1149)
48
(1232)
44
(1127)
19
(492)
32
(803)
32
(822)
47
(1172)
199
(5050)
199
(5050)
199
(5050)
199
(5050)
196
(4974)
196
(4974)
196
(4974)
196
(4974)
57
(1453)
57
(1453)
74
(1886)
93
(2343)
49
(1250)
49
(1250)
66
(1682)
89
(2241)
EVAP
2
PASS
COND
2
PASS
10
10
12
10
12
12
14
14
Note: See notes on page 66.
72
Catalog WSC/WDC-4
Figure 30, WDC 100, 1200 to 1700 tons, (4200 to 5950 kW), 16 foot shells
WDC 113, 1400 to 1900 tons, (4900 to 6700 kW), 16 foot shells
WDC 126, 1600 to 2700 tons, (5600 to 9450 kW), 16 foot shells
ADJUSTABLE OPERATOR
INTERFACE PANEL
UNIT
CONTROL
BOX
1” FPT VESSEL RELIEF
VALVE CONNECTIONS
EVAPORATOR
1.5” FPT OIL COOLER CONNECTION
CONDENSER
OUT
IN
OUT
IN
VESSEL CODE
OVERALL LENGTH
1&3
EVAP
COND
PASS
A
E3616 C3616
E4216 C4216
E4816 C4816
OVERALL
OVERALL
2
HEAD CONN HEIGHT WIDTH W/O
STARTER
PASS BOTH ENDS
A
224
218
(5692) (5528)
224
219
(5692) (5554)
230
224
(5848) (5703)
CONNECTIONS
CENTER OF GRAVITY
W/O STARTER
FOOTPRINT
A
B
C
X
Y
Z
D
E
F
G
224
(5692)
224
(5692)
230
(5848)
104
(2652)
107
(2722)
116
(2956)
95
(2419)
100
(2545)
110
(2792)
93
(2353)
94
(2381)
95
(2400)
51
(1292)
50
(1254)
52
(1318)
40
(1003)
44
(1105)
51
(1292)
199
(5050)
199
(5050)
199
(5050)
196
(4974)
196
(4974)
196
(4974)
95
(2419)
100
(2545)
110
(2792)
87
(2216)
92
(2342)
102
(2589)
EVAP
2
PASS
COND
2
PASS
12
12
14
16
18
18
Notes:
1. E3616/C3616 is available on WDC 100 only.
2. See notes on page 66.
Catalog WSC/WDC-4
73
Figure 31, WDC 100, 1200 to 1700 tons, (4200 to 5950 kW), 20 foot shells
WDC 113, 1400 to 1900 tons, (4900 to 6700 kW), 20 foot shells
WDC 126, 1600 to 2700 tons, (5600 to 9450 kW), 20 foot shells
ADJUSTABLE OPERATOR
INTERFACE PANEL
B
UNIT
CONTROL
BOX
EVAPORATOR
1.5” FPT OIL COOLER CONNECTION
Y
1” FPT VESSEL RELIEF
VALVE CONNECTIONS
CONDENSER
X
A
D
OUT
IN
FOOTPRINT
OUT
IN
Y
Z
C
VESSEL CODE
OVERALL LENGTH
1&3
EVAP
COND
PASS
A
E4220 C4220
E4820 C4820
OVERALL
OVERALL
HEAD CONN HEIGHT WIDTH W/O
STARTER
PASS BOTH ENDS
2
A
272
267
(6909) (6772)
276
271
(7010) (6890)
CONNECTIONS
CENTER OF GRAVITY
FOOTPRINT
A
B
C
X
Y
Z
D
E
F
G
272
(6909)
276
(7010)
102
(2591)
111
(2810)
92
(2343)
104
(2648)
117
(2991)
118
(3007)
46
(1165)
49
(1238)
36
(921)
43
(1105)
247
(6269)
247
(6269)
244
(6193)
244
(6193)
92
(2343)
104
(2648)
84
(2140)
96
(2444)
EVAP
2
PASS
COND
2
PASS
14
16
18
18
Note: See notes on page 66.
74
Catalog WSC/WDC-4
Marine Water Boxes (WSC)
Marine water boxes are an available option on all evaporator and condenser sizes. Epoxy coating of the water boxes and
clad tube sheets are available for extreme duty applications. Caution: There is some nomenclature confusion in the
industry. McQuay refers to our standard dished heads as “dished heads”. Some manufacturers refer to them, or similar
devices as “water boxes”. They are not “marine water boxes” with removable end covers as illustrated below.
REAR FACING ONLY
REAR FACING ONLY
REAR FACING ONLY
Dimensions with Victaulic or Flanged Connections (150 PSI Non-ASME - Victaulic Connection)
Evap.
Dia. 'AAA'
E18 8.625
E20 8.625
E22 10.750
E26 10.750
E30 14.000
E36 16.000
E42 20.000
E48 24.000
'BBB'
15.00
16.00
17.00
19.00
21.00
24.00
27.00
30.00
1 PASS
'CCC 'DDD'
19.25 18.00
19.25 18.00
21.25 20.00
21.25 20.00
28.50 26.50
29.50 28.00
34.75 33.00
38.50 36.50
'EEE'
9.00
9.00
10.00
10.00
13.25
14.00
16.50
18.25
'AAA'
6.625
6.625
8.625
8.625
10.750
12.750
14.000
18.00
'BBB'
15.00
16.00
17.00
19.00
21.00
24.00
27.00
30.00
2 PASS
'CCC' 'DDD'
19.25 18.00
19.25 18.00
21.25 20.00
21.25 20.00
28.50 26.50
29.50 28.00
34.75 33.00
38.50 36.50
3 PASS
'EEE' 'FFF' 'GGG' 'AAA' 'BBB' 'CCC' 'DDD' 'EEE' 'FFF'
9.00 4.78 21.00 4.500 15.00 19.25 18.00 9.00 5.85
9.00 5.63 16.00 4.500 16.00 19.25 18.00 9.00 6.69
10.00 5.59 23.00 5.563 17.00 21.25 20.00 10.00 7.12
10.00 7.07 19.00 6.625 19.00 21.25 20.00 10.00 8.07
13.25 8.13 21.00 6.625 21.00 28.50 26.50 13.25 10.19
14.00 9.75 24.00 8.625 24.00 29.50 28.00 14.00 11.81
16.50 11.63 27.00 10.750 27.00 34.75 33.00 16.50 13.25
18.25 12.50 36.00 12.750 30.00 38.50 36.50 18.25 15.13
Cond.
1 PASS
2 PASS
3 PASS
Dia. 'AAA' 'BBB' 'CCC 'DDD' 'EEE' 'AAA' 'BBB' 'CCC' 'DDD' 'EEE' 'FFF' 'GGG' 'AAA' 'BBB' 'CCC' 'DDD' 'EEE' 'FFF'
C16 8.625 14.00 15.25 14.00 7.00 5.563 14.00 15.25 14.00 7.00 4.35 14.00
C18 8.625 15.00 19.25 18.00 9.00 6.625 15.00 19.25 18.00 9.00 4.78 15.00
C20 8.625 16.00 19.25 18.00 9.00 6.625 16.00 19.25 18.00 9.00 5.63 16.00
Consult local sales office
C22 10.750 17.00 21.25 20.00 10.00 8.625 17.00 21.25 20.00 10.00 5.59 23.00
C26 10.750 19.00 21.25 20.00 10.00 8.625 19.00 21.25 20.00 10.00 7.07 19.00
C30 14.000 21.00 28.50 26.50 13.25 10.750 21.00 28.50 26.50 13.25 8.13 21.00
C36 16.000 24.00 30.25 28.00 14.00 12.750 24.00 30.25 28.00 14.00 9.75 24.00
C42 20.000 27.00 32.50 30.00 15.00 14.000 27.00 32.50 30.00 15.00 11.63 27.00
C48 24.000 30.00 39.5 36.00 18.25 18.000 30.00 39.5 36.50 18.25 12.50 36.50
1. Dimensions in inches (mm).
2. Flanges are ANSI raised face. Mating flanges by others.
3. Some condensers with flanges can have staggered connections due to flange interference. Consult factory.
4. Flange add 0.5 inches to the distance from the vertical centerline to the flange faces than shown with victaulic couplings
Catalog WSC/WDC-4
75
Marine Water Boxes (WDC)
FIGURE 1
FIGURE 2
2 and 4 Pass Cond. (Except 18 in. 2 Pass)
Evap. And Cond. 1 Pass
Cover
Thickness
“C”
Nozzle Flanges
Are Optional
.50
“D”
“A”
“B”
“F”
FIGURE 3
FIGURE 4
2 and 4 Pass Cond. (Except 18 in. 2 Pass)
All 2 Pass Evap. - All 3 Pass Cond.
18 in. 2 Pass Cond.
Nozzle Flanges
Are Optional
Nozzle Flanges
Are Optional
“E”
“E”
“E”
“E”
.50
.50
“D”
“D”
Notes:
Shell
Vessel
O.D.
16
18
20
22
26
30
36
42
48
Evap
Cond
Evap
Cond
Evap
Evap
Cond
Evap
Cond
Evap
Cond
Evap
Cond
Evap
Cond
Evap
Cond
1. Evaporator connections are front facing only.
2. Condenser connections are rear facing only.
A
B
C
5
5
7
7
7
8
8
8
8
12
12
12
12
13
13
-----
13.00
13.00
17.25
17.25
17.25
19.50
19.50
19.50
19.50
27.75
27.75
28.00
28.00
30.50
30.50
---------
14.00
14.00
18.00
18.00
18.00
20.00
20.00
20.00
20.00
28.00
28.00
28.00
28.00
30.00
30.00
36.00
36.00
Outline Dimensions
D
Fig 2
Fig 3
Fig 4
14.50 - - - - - 22.50
14.50
16.50
22.50
22.50 - - - - - 22.50
16.50 - - - - - 22.50
22.50 - - - - - 22.50
22.50 - - - - - 22.50
22.50
22.50
22.50
22.50 - - - - - 22.50
22.50
22.50
22.50
24.50 - - - - - 24.50
27.50
27.50
27.50
27.50 - - - - - 27.50
27.50
27.50
27.50
27.50 - - - - - 35.50
27.50
27.50
27.50
36.00 - - - - - 40.00
36.00
36.00
-----
E
Fig 3
----4.35
----------------5.62
----7.07
----8.12
----9.75
----11.63
----11.50
Fig 4
6.94
6.94
7.94
7.06
7.88
10.12
9.93
11.69
11.69
13.62
13.00
16.50
16.33
19.38
11.63
22.64
-----
F
15.00
15.00
19.25
19.25
19.25
21.50
21.50
21.50
21.50
29.75
29.75
30.00
30.00
33.00
33.00
39.25
39.25
Connections
Cover
Thick- Pipe Size For Passes
ness 1P
2P
3P
4P
1.00
8
5
4
4
1.25
8
6
5
4
1.25
8
6
5
4
1.50
10
8
6
5
1.50
10
8
8
6
1.75
14
10
8
8
2.00
16
12
10
8
2.00
20
16
12
10
2.75
---
18
---
---
Notes: See notes on previous page.
76
Catalog WSC/WDC-4
Table 13, Unit Weights, Single Compressor, WSC
1809 / 1609
1812 / 1612
2009 / 1609
2012 / 1612
2009 / 1809
2012 / 1812
2209 / 2009
2212 / 2012
Unit Refrig.
Charge (1)
Lbs. (kg)
341 (154)
447 (202)
395 (179)
519 (235)
410 (186)
539 (244)
479 (216)
631 (287)
Max. Unit Weight Without Starter
Shipping
Operating
lbs. (kg)
lbs. (kg)
5771 (2618)
6168 (2798)
6504 (2950)
7004 (3177)
6130 (2781)
6591 (2990)
6933 (3145)
7510 (3407)
6395 (2901)
6932 (3144)
7267 (3296)
7938 (3601)
7038 (3192)
7760 (3520)
8077 (3664)
8972 (4070)
Max. Unit Weight With Starter
Shipping
Operating
lbs. (kg)
lbs. (kg)
6972 (3162)
7368 (3342)
7704 (3495)
8204 (3721)
7330 (3326)
7791 (3534)
8133 (3689)
8711 (3951)
7595 (3445)
8132 (3689)
8467 (3841)
9138 (4145)
8238 (3737)
8960 (4064)
9277 (4208)
10172 (4614)
WSC063
WSC063
WSC063
WSC063
WSC063
WSC063
WSC063
WSC063
WSC063
WSC063
WSC063
WSC063
2009 / 1809
2012 / 1812
2209 / 2009
2212 / 2012
2209 / 2209
2212 / 2212
2609 / 2209
2612 / 2212
2609 / 2609
2612 / 2612
3009 / 2609
3012 / 2612
410 (186)
539 (244)
479 (217)
631 (286)
495 (224)
651 (295)
651 (295)
859 (389)
686 (311)
905 (410)
825 (374)
1098 (497)
8412(3816)
9284 (4211)
9119 (4136)
10182 (4619)
9416 (4271)
10557 (4789)
10248 (4648)
11577 (5251)
10984 (4982)
12494 (5667)
12892 (5848)
13903 (6306)
8949 (4059)
9955 (4516)
9841 (4464)
11077 (5025)
10235 (4643)
11570 (5248)
11258 (5107)
12817 (5806)
12228 (5547)
14020 (6359)
14246 (6462)
15569 (7062)
9612 (4360)
10484 (4756)
10319 (4681)
11382 (5163)
10616 (4815)
11757 (5333)
11448 (5193)
12777 (5796)
12184 (5527)
13694 (6203)
14092 (6392)
15103 (6851)
10149 (4604)
11155 (5060)
11040 (5008)
12277 (5569)
11435 (5187)
12770 (5792)
12458 (5651)
14017 (6358)
13428 (6091)
15220 (6904)
15446 (7006)
16769 (7606)
WSC079
WSC079
WSC079
WSC079
WSC079
WSC079
WSC079
WSC079
WSC079
WSC079
WSC079
WSC079
2209 / 2209
2212 / 2212
2609 / 2209
2612 / 2212
2609 / 2609
2612 / 2612
3009 / 2609
3012 / 2612
3009 / 3009
3012 / 3012
3609 / 3009
3612 / 3012
495 (224)
651 (295)
651 (295)
859 (389)
686 (311)
905 (410)
825 (374)
1098 (497)
855 (387)
1147 (520)
1173 (531)
1563 (708)
10140 (4600)
11281 (5117)
10980 (4981)
12309 (5592)
11716 (5314)
13226 (5999)
12892 (5848)
14635 (6638)
14076 (6385)
16119 (7312)
15913 (7218)
18340 (8319)
10959 (4971)
12294 (5577)
11990 (5439)
13548 (6145)
12960 (5879)
14752 (6692)
14246 (6462)
16301 (7394)
15644 (7096)
18061 (8192)
17929 (8133)
20807 (9438)
11340 (5144)
12481 (5661)
12180 (5525)
13509 (6128)
12916 (5859)
14426 (6544)
14092 (6392)
15835 (7183)
15276 (6929)
17319 (7856)
17113 (7762)
19540 (8863)
12159 (5515)
13494 (6121)
13190 (5983)
14749 (6690)
14160 (6423)
15952 (7236)
15446 (7006)
17501 (7938)
16844 (7640)
19261 (8737)
19129 (8677)
22007 (9982)
WSC087
WSC087
WSC087
WSC087
WSC087
WSC087
WSC087
WSC087
WSC087
WSC087
WSC087
2609 / 2209
2612 / 2212
2609 / 2609
2612 / 2612
3009 / 2609
3012 / 2612
3009 / 3009
3012 / 3012
3609 / 3009
3612 / 3012
3612 / 3612
651 (295)
859 (389)
686 (311)
905 (410)
825 (374)
1098 (497)
862 (390)
1147 (520)
1173 (531)
1563 (708)
1635 (740)
10980 (4981)
12309 (5583)
11716 (5314)
13226 (5999)
12892 (5848)
14635 (6638)
14076 (6385)
16118 (7311)
15913 (7218)
18339 (8319)
20584 (9337)
11990 (5439)
13549 (6146)
12960 (5879)
14752 (6692)
14246 (6462)
16301 (7394)
15644 (7096)
18060 (8192)
17929 (8133)
20806 (9438)
23799 (10795)
12180 (5525)
13509 (6128)
12916 (5859)
14426 (6544)
14092 (6392)
15835 (7183)
15276 (6929)
17318 (7855)
17113 (7762)
19539 (8863)
21784 (9881)
13190 (5983)
14749 (6690)
14160 (6423)
15592 (7073)
15446 (7006)
17501 (7938)
16844 (7640)
19260 (8736)
19129 (8677)
22006 (9982)
24999 (11340)
WSC100
WSC100
WSC100
WSC100
WSC100
WSC100
3012 / 3012
3612 / 3012
3612 / 3612
4212 / 3612
4212 / 4212
4812 / 4212
1147 (520)
1563 (708)
1635 (740)
2081 (943)
2164 (980)
2688 (1217)
19397 (8798)
21578 (9788)
23826 (10807)
26457 (12001)
29298 (13290)
32024 (14526)
21339 (9679)
24045 (10907)
27041 (12266)
30260 (13726)
34024 (15433)
37623 (17066)
20597 (9343)
22778 (10332)
25026 (11352)
27657 (13545)
30498 (13834)
33224 (15070)
22539 (10224)
25245 (11451)
28241 (12810)
31460 (14270)
35224 (15978)
38823 (17610)
WSC113
WSC113
WSC113
WSC113
WSC113
WSC113
WSC113
3012 / 3012
3612 / 3012
3612 / 3612
4212 / 3612
4212 / 4212
4812 / 4212
4812 / 4812
1147 (520)
1563 (708)
1635 (740)
2081 (943)
2164 (980)
2688 (1217)
2867 (1299)
19397 (8798)
21578 (9788)
23826 (10807)
26457 (12001)
29298 (13290)
32024 (14526)
35016 (15883)
21339 (9679)
24045 (10907)
27041 (12266)
30260 (13726)
34024 (15433)
37623 (17066)
41817 (18968)
20597 (9343)
22778 (10332)
25026 (11352)
27657 (13545)
30498 (13834)
33224 (15070)
36216 (16427)
22539 (10224)
25245 (11451)
28241 (12810)
31460 (14270)
35224 (15978)
38823 (17610)
43017 (19513)
WSC126
WSC126
WSC126
WSC126
WSC126
WSC126
3612 / 3012
3612 / 3612
4212 / 3612
4212 / 4212
4812 / 4212
4812 / 4812
1563 (708)
1635 (740)
2081 (943)
2164 (980)
2164 (980)
2867 (1299)
21680 (9834)
23928 (10854)
26457 (12001)
29298 (13290)
32024 (14526)
35016 (15883)
24147 (10953)
27143 (12312)
30260 (13726)
34024 (15433)
37623 (17066)
41817 (18968)
22880 (10378)
25128 (11398)
27657 (12545)
30498 (13834)
33224 (15070)
36216 (16427)
25347 (11497)
28343 (12856)
31460 (14270)
35224 (15978)
38823 (17610)
43017 (19513)
Unit
Evaporator /
Condenser Size
WSC050
WSC050
WSC050
WSC050
WSC050
WSC050
WSC050
WSC050
NOTE: (1) Shipping and operating weights include the refrigerant charge.
Catalog WSC/WDC-4
77
Table 14, Dual Compressor, WDC
Max. Unit Weight Without Starter
Shipping
Operating
lbs. (kg)
lbs. (kg)
Max. Unit Weight With Starter
Shipping
Operating
lbs. (kg)
lbs. (kg)
Unit
Evaporator /
Condenser Size
WDC050
1812 / 1612
8861 (4019)
9564 (4338)
11261 (5108)
11964 (5427)
WDC050
1812 / 1812
9217 (4181)
10018 (4544)
11617 (5269)
12418 (5633)
WDC050
1816 / 1816
10468 (4748)
11268 (5111)
12868 (5837)
13668 (6200)
WDC050
2012 / 1812
9671 (4387)
10534 (4778)
12071 (5475)
12934 (5867)
WDC050
2016 / 1816
11024 (5000)
12110 (5493)
13424 (6089)
14510 (6582)
WDC050
2212 / 2212
11123 (5045)
12403 (5626)
13523 (6134)
14803 (6715)
WDC050
2216 / 2216
12874 (5840)
14485 (6470)
15274 (6928)
16885 (7659)
WDC050
2412 / 2212
12348 (5601)
13836 (6276)
14748 (6690)
16236 (7365)
WDC050
2416 / 2216
13957 (6331)
15820 (7176)
16357 (7419)
18220 (8264)
WDC050
2612 / 2212
12836 (5822)
14428 (6544)
15236 (6911)
16828 (7633)
WDC050
2616 / 2216
14642 (6642)
16643 (7549)
17042 (7730)
19043 (8638)
WDC063
2416 / 2416
18673 (8470)
20422 (9263)
21407 (9710)
23156 (10503)
WDC063
2416 / 2616
19365 (8784)
21294 (9577)
22099 (10024)
23848 (10817)
WDC063
2616 / 2416
19282 (8746)
21207 (9639)
22016 (9986)
23763 (10779)
WDC063
2616 / 2616
20025 (9083)
22091 (9939)
22759 (10323)
24646 (11179)
WDC063
3016 / 3016
23545 (10680)
26405 (11830)
26279 (11920)
28815 (13070)
WDC063
3616 / 3016
27763 (12604)
31018 (14082)
30163 (13694)
33418 (15172)
WDC063
3616 / 3616
32027 (14540)
35115 (15942)
33427 (15176)
37515 (17032)
WDC079
3016 / 3016
25131 (11399)
27671 (12551)
27531 (12488)
30071 (13640)
WDC079
3616 / 3016
28763 (13047)
32018 (14523)
31163 (14135)
34418 (15612)
WDC079
3616 / 3616
32027 (14527)
36115 (16382)
34427 (15616)
38515 (17470)
WDC079
4216 / 4216
44470 (20189)
51463 (23364)
47204 (21431)
54197 (24605)
WDC087
3016 / 3016
26157 (11865)
28697 (13017)
28891 (13105)
31431 (14257)
WDC087
3616 / 3016
29789 (13512)
33044 (14989)
32523 (14752)
35778 (15322)
WDC087
3616 / 3616
33053 (14993)
37141 (16847)
35787 (16233)
39875 (18087)
WDC087
4216 / 4216
44470 (20189)
51463 (23364)
47204 (21431)
54197 (24605)
WDC100
3616 / 3616
41816 (18967)
46513 (21098)
See Note
See Note
WDC100
4216 / 4216
50470 (22893)
57463 (26065)
See Note
See Note
WDC100
4816 / 4816
59185 (26846)
68996 (31296)
See Note
See Note
WDC100
4220 / 4220
54802 (24858)
63248 (28689)
See Note
See Note
WDC100
4820 / 4820
65964 (29921)
77698 (35243)
See Note
See Note
WDC113
3616 / 3616
41816 (18967)
46513 (21098)
See Note
See Note
WDC113
4216 / 4216
50470 (22893)
57463 (26065)
See Note
See Note
WDC113
4816 / 4816
59185 (26846)
68996 (31296)
See Note
See Note
WDC113
4220 / 4220
54802 (24858)
63248 (28689)
See Note
See Note
WDC113
4820 / 4820
65964 (29921)
77698 (35243)
See Note
See Note
WDC126
4216 / 4216
50470 (22893)
57463 (26065)
See Note
See Note
WDC126
4816 / 4816
59185 (26846)
68996 (31296)
See Note
See Note
WDC126
4220 / 4220
54802 (24858)
63248 (28689)
See Note
See Note
WDC126
4820 / 4820
65964 (29921)
77698 (35243)
See Note
See Note
Note: Unit not available with factory mounted starters.
78
Catalog WSC/WDC-4
Supplemental Publications
McQuay has a large number of publications and software applications relating to centrifugal
chillers and to chilled water systems in general. The latest versions are available on
www.mcquay.com or from the local McQuay sales office. Some of the available material is listed
below:
Catalogs/Manuals
•
PM Templifier, a catalog with detailed information on the capacities and application of
Templifier™ Heat Pump Water Heaters.
•
PM Starter, a catalog with detailed information on unit mounted and freestanding starters for
McQuay centrifugal chillers. It contains descriptions, dimensions, lug sizes and other
valuable information.
•
IOMM WSCWDC, the installation an operating manual for centrifugal chillers.
Application Guides
•
AG 31-002, Centrifugal Chiller Fundamentals, a 20 page general guide, discussing
compressor theory, vessel design and pass optimization, capacity control, prime movers and
dual compressor chillers.
•
AG 31-003, Chiller Plant Design, a 94 page comprehensive guide on designing chilled water
plants. Some of the subjects included are water temperatures and ranges, mechanical room
safety, parallel versus series flow, primary/secondary systems, free cooling, heat recovery, and
many more.
•
AG 31-007 Refrigerant Application Guide, discusses refrigerant chemistry, specific refrigerant
characteristics, phase-outs, substitutes, and what the future holds.
Application Bulletins
•
Application Bulletin, Issue No 1, Centrifugal Chillers with VFDs, discusses speed/lift
relationships, condenser water relief, and applying VFDs.
•
Application Bulletin, Issue No 4, Overview of ASHRAE Standard 90.1-1999, summarizes
HVAC equipment efficiency requirements.
MicroTech II Controls
•
A/SP 31-171, McQuay Chiller Systems with Protocol Selectability™ BAS communication
modules, discusses the benefits and application of McQuay’s MicroTech II controller with
Protocol Selectability interface with BAS.
•
A/SP 31-187, McQuay Chiller System Manager (CSM), contains a description of the CSM
panel used for control of up to twelve chillers in a chilled water plant.
•
IM 735, installation manual for LONWORKS communication module on chillers.
•
IM 736, installation manual for BACnet communication module on chillers.
•
IM 743, installation manual for Modbus communication module on chillers.
•
IM 781, installation manual for Chiller System Manager (CSM).
•
OM 780, operating manual for the Chiller System Manager (CSM).
Software
•
•
Energy Analyzer™, gives fast answers, with life cycle analysis, for optimizing chiller plant
type and terminal equipment.
Acoustic Analyzer™, with known equipment sound levels, this program will provide sound
levels at various distances, with various wall configurations, giving total site results.
Catalog WSC/WDC-4
79
Specifications
SECTION 15XXX
CENTRIFUGAL CHILLERS
SINGLE COMPRESSOR
PART 1 — GENERAL
1.1 SUMMARY
Section includes design, performance criteria, refrigerants, controls, and installation requirements for
water-cooled centrifugal chillers.
1.2 REFERENCES
Comply with the following codes and standards
ARI 550/590
NEC
ANSI/ASHRAE 15
OSHA as adopted by the State
ASME Section VIII
1.3 SUBMITTALS
Submittals shall include the following:
A.
Dimensioned plan and elevation view drawings, including motor starter cabinet, required
clearances, and location of all field piping and electrical connections.
B.
Summaries of all auxiliary utility requirements such as: electricity, water, air, etc.
Summary shall indicate quality and quantity of each required utility.
C.
Diagram of control system indicating points for field interface and field connection.
Diagram shall fully depict field and factory wiring.
D.
Manufacturer’s certified performance data at full load plus IPLV or NPLV.
E
Before shipment, submit a certification of satisfactory completion of factory run test signed
by a company officer. The test shall be performed on an ARI Certified test stand and
conducted according to ARI Standard 550/590.
F
Installation and Operating Manuals.
1.4 QUALITY ASSURANCE
A.
Qualifications: Equipment manufacturer must specialize in the manufacture of the
products specified and have five years experience with the equipment and refrigerant
offered.
B.
Regulatory Requirements: Comply with the codes and standards in Section 1.2.
C.
Chiller manufacturer plant shall be ISO Registered.
1.5 DELIVERY AND HANDLING
A.
Chillers shall be delivered to the job site completely assembled and charged with
refrigerant and oil.
B.
Comply with the manufacturer’s instructions for rigging and transporting units. Leave
protective covers in place until installation.
1.6 WARRANTY
The refrigeration equipment manufacturer’s warranty shall be for a period of (one) -- OR -- (two) -Or-- (five) years from date of equipment start up or 18 months from shipment whichever occurs
first. The warranty shall include parts and labor costs for the repair or replacement of defects in
material or workmanship.
1.7 MAINTENANCE
Chiller maintenance shall be the responsibility of the owner with the following exceptions:
A.
The manufacturer shall provide the first year scheduled oil and filter change if required.
B.
The manufacturer shall provide first year purge unit maintenance if required.
80
Catalog WSC/WDC-4
PART 2 — PRODUCTS
2.1 ACCEPTABLE MANUFACTURERS
A.
McQuay International
B.
(Approved Equal)
2.2 UNIT DESCRIPTION
Provide and install as shown on the plans a factory-assembled, factory charged, and factory runtested water-cooled packaged chiller. Each unit shall be complete with a single-stage hermetic
centrifugal compressor with lubrication and control system, factory mounted starter, evaporator,
condenser, refrigerant control device and any other components necessary for a complete and
operable chiller package.
2.3 DESIGN REQUIREMENTS
A.
General: Provide a complete water-cooled hermetic centrifugal compressor water-chilling
package as specified herein. Machine shall be provided according to referenced standards
Section 1.2. In general, unit shall consist of a compressor, condenser, evaporator,
lubrication system, starter and control system.
Note: Chillers shall be charged with a refrigerant such as R-134a, not subject to the
Montreal Protocol and the U. S. Clean Air Act.
B.
Performance: Refer to schedule on the drawings. The chiller shall be capable of stable
operation to ten percent of full load with standard ARI entering condensing water relief
without the use of hot gas bypass.
C.
Acoustics: Sound pressure levels for the complete unit shall not exceed the following
specified levels. Provide the necessary acoustic treatment to chiller as required. Sound
data shall be measured according to ARI Standard 575-87. Data shall be in dB. Data shall
be the highest levels recorded at all load points. Test shall be in accordance with ARI
Standard 575.
Octave Band
63
125
250
500
1000
2000
4000
8000 dba
____
____
____
____
____
____
____
____ ____
2.4 CHILLER COMPONENTS
A.
Compressor:
1.
Unit shall have a single-stage hermetic centrifugal compressor. Casing design
shall ensure major wearing parts, main bearings, and thrust bearings are
accessible for maintenance and replacement. The lubrication system shall protect
machine during coast down period resulting from a loss of electrical power.
2.
The impeller shall be statically and dynamically balanced. The compressor shall
be vibration tested and not exceed a level of 0.14 IPS.
3.
Movable inlet guide vanes actuated by an internal oil pressure driven piston shall
accomplish unloading. Compressors using an unloading system that requires
penetrations through the compressor housing or linkages, or both that must be
lubricated and adjusted are acceptable provided the manufacturer provides a fiveyear inspection agreement consisting of semi-annual inspection, lubrication, and
annual change out of any compressor seals. A statement of inclusion must
accompany any quotations.
4.
If the compressor is not equipped with guide vanes for each stage and movable
discharge diffusers, then furnish hot gas bypass and select chillers at 5% lower
kW/ton than specified to compensate for bypass inefficiency at low loads.
B.
Lubrication System: The compressor shall have an independent lubrication system to
provide lubrication to all parts requiring oil. Provide a heater in the oil sump to maintain
oil at sufficient temperature to minimize affinity of refrigerant, and a thermostatically
controlled water-cooled oil cooler. Coolers located inside the evaporator or condenser are
not acceptable due to inaccessibility. A positive displacement oil pump shall be powered
through the unit control transformer.
Catalog WSC/WDC-4
81
C.
D.
E.
82
Refrigerant Evaporator and Condenser:
1. Evaporator and condenser shall be of the shell-and-tube type, designed, constructed,
tested and stamped according to the requirements of the ASME Code, Section VIII.
Regardless of the operating pressure, the refrigerant side of each vessel will bear the
ASME stamp indicating compliance with the code and indicating a test pressure of 1.1
times the working pressure, but not less than 100 psig. Provide intermediate tube
supports at a maximum of 24 inch spacing.
2. Tubes shall be enhanced for maximum heat transfer, rolled into steel tube sheets and
sealed with Locktite® or equal sealer. The tubes shall be individually replaceable.
3. Provide isolation valves and sufficient volume to hold the full refrigerant charge in the
condenser or provide a separate pumpout system with storage tank..
4. The water sides shall be designed for a minimum of 150 psi or as specified elsewhere.
Vents and drains shall be provided.
5. Evaporator minimum refrigerant temperature shall be 33°F.
6. An electronic or thermal refrigerant expansion valve shall control refrigerant flow to
the evaporator. Fixed orifice devices or float controls with hot gas bypass are not
acceptable because of inefficient control at low load conditions. The liquid line shall
have a moisture indicating sight glass.
7. The evaporator and condenser shall be separate shells. A single shell containing both
vessel functions is not acceptable because of the possibility of internal leaks.
8. Reseating type spring loaded pressure relief valves according to ASHRAE-15 safety
code shall be furnished. The evaporator shall be provided with single or multiple
valves. The condenser shall be provided with dual relief valves equipped with a
transfer valve so one valve can be removed for testing or replacement without loss of
refrigerant or removal of refrigerant from the vessel. Rupture disks are not acceptable.
9. The evaporator, suction line, and any other component or part of a component subject
to condensing moisture shall be insulated with UL recognized 3/4 inch closed cell
insulation. All joints and seams shall be carefully sealed to form a vapor barrier.
10. Provide factory-mounted thermal dispersion flow switches on each vessel to prevent
unit operation with no flow.
Prime Mover: Squirrel cage induction motor of the hermetic type of sufficient size to
efficiently fulfill compressor horsepower requirements. Motor shall be liquid refrigerant
cooled with internal thermal overload protection devices embedded in the winding of each
phase. Motor shall be compatible with the starting method specified hereinafter. If the
Contractor chooses to provided an open drive motor or compressor, verify in the submittal
that the scheduled chiller room ventilation system will accommodate the additional heat
and maintain the equipment room at design indoor temperature based on 95°F outdoor
ambient ventilation air available.
If additional cooling is required, manufacturer shall be responsible for the installation,
wiring and controls of a cooling system. Chiller selection shall compensate for tonnage
and efficiency loss to make certain the owner is not penalized.
Motor Starter:
1.
The main motor starter is to be factory mounted and fully wired to the chiller
components and factory tested during the run test of the unit.
-- OR -The main motor starter is to be furnished by the chiller manufacturer and shipped
loose for floor mounting and field wiring to the chiller package. It shall be freestanding with NEMA-1 enclosure designed for top entry and bottom exit and with
front access.
2.
For open drive air-cooled motors the chiller manufacturer shall be responsible for
providing the cooling of the refrigeration machinery room. The sensible cooling
load shall be based on the total heat rejection to the atmosphere from the
refrigeration units.
Catalog WSC/WDC-4
3.
F.
Catalog WSC/WDC-4
For open motor units, an oil reservoir shall collect any oil and refrigerant that
leaks past the seal. A float device shall be provided to open when the reservoir is
full, directing the refrigerant/oil mixture back into the compressor housing.
Manufacturer shall warrant the shaft seal, reservoir, and float valve system against
leakage of oil and refrigerant to the outside of the refrigerating unit for a period of
5 years from the initial start-up including parts and labor to replace a defective
seal and any refrigerant required to trim the charge original specifications.
4.
The starter must comply with the requirements of Section 1.2.
Low Voltage (200 through 600 volts) motor controllers are to be continuous
5.
duty AC magnetic type constructed according to NEMA standards for Industrial
Controls and Systems (ICS) and capable of carrying the specified current on a
continuous basis. The starter shall be:
Autotransformer - The autotransformer starter shall be of the closed transition
type and equipped with multiple taps for 80%, 65%, 50%, and set up for the 65%
tap. A clearly marked timer shall be adjustable from 0 to 30 seconds.
-- OR -Wye-Delta Closed Transition - The wye contactor shall be capable of handling
33% of the delta locked rotor current and be equipped with properly sized
resistors to provide a smooth transition. The resistors shall be protected with a
transition resistor protector, tripping in a maximum of two seconds, locking out
the starter, and shall be manually reset. A clearly marked transition timer shall be
adjustable from 0 to 30 seconds.
-- OR -Solid-State Reduced Voltage - Starter shall be furnished with silicon controlled
rectifiers (SCR) connected for starting and include a bypass contactor. When
operating speed is reached, the bypass contactor shall be energized removing the
SCRs from the circuit during normal running.
6.
The starter shall be coordinated with the chiller package(s) making certain all
terminals are properly marked according to the chiller manufacturer’s wiring
diagrams.
7.
The starters shall be equipped with redundant motor control relays (MCR) with
coils in parallel. The relays interconnect the starters with the unit control panels
and directly operate the main motor contactors. The MCRs shall constitute the
only means of energizing the motor contacts.
8.
The main contactors shall have a normally open and a normally closed auxiliary
contact rated at 125VA pilot duty at 115 VAC. An additional set of normally open
contacts shall be provided for each MCR.
9.
There shall be electronic overloads in each phase set at 107% of the rated load
amps of each motor. Overloads shall be manual reset and shall de-energize the
main contactors when the overcurrent occurs. The overloads shall be adjustable
and selected for mid-range. Overloads shall be adjusted for a locked rotor trip
time of 8 seconds at full voltage and must trip in 60 seconds or less at reduced
voltage (33% of delta LRA).
10.
Each starter shall have a current transformer and adjustable voltage dropping
resistor(s) to supply a 5.0 VAC signal at full load to the unit control panels.
11.
Each starter shall be equipped with a line-to-115 VAC control transformer, fused
in both the primary and secondary, to supply power to the control panels, oil
heaters and oil pumps.
12.
Each starter shall include the following protective devices:
a) Phase failure and reversal protection
-ORVariable Frequency Drive
The chiller shall be equipped with a Variable Frequency Drive (VFD) to automatically
regulate compressor speed in response to cooling load and compressor pressure lift. The
83
chiller control shall coordinate compressor speed and guide vane position to optimize
chiller efficiency.
1.
A digital regulator shall provide V/Hz control.
2.
The VFD shall have 110% continuous overload of continuous amp rating with no
time limit, PWM (pulse width modulated) output, IGBT (insulated gate bipolar
transistors) power technology, full power rating at 2kHz, DC bus inductor
(choke), and wireless construction.
3.
Units 273 amps and below shall be air-cooled, units above 274 amps shall be
water-cooled. All heat producing devices shall be contained in a single heatsink
with single inlet and out connections for the connection of chilled water. When
factory mounted on the chiller package, the water connections shall be piped and
leak tested at the factory.
Medium Voltage (601 through 5000 volts) and High Voltage (5001 through 7200 volts).
The starter shall be:
1. Solid-State Reduced Voltage - Starter shall be furnished with silicon controlled
rectifiers (SCR) connected for starting and include a bypass contactor. When
operating speed is reached, the bypass contactor shall be energized removing the
SCRs from the circuit during normal running.
2. The starter shall be coordinated with the chiller package(s) making certain all
terminals are properly marked according to the chiller manufacturer’s wiring
diagrams.
3. The starters shall be equipped with redundant motor control relays (MCR) with coils
in parallel. The relays interconnect the starters with the unit control panels and
directly operate the main motor contactors. The MCRs shall constitute the only means
of energizing the motor contacts.
4. The main contactors shall have a normally open and a normally closed auxiliary
contact rated at 125VA pilot duty at 115 VAC. An additional set of normally open
contacts shall be provided for each MCR.
5. There shall be electronic overloads in each phase set at 107% of the rated load amps
of each motor. Overloads shall be manual reset and shall de-energize the main
contactors when the overcurrent occurs. The overloads shall be adjustable and
selected for mid-range. Overloads shall be adjusted for a locked rotor trip time of 8
seconds at full voltage and must trip in 60 seconds or less at reduced voltage (33% of
delta LRA).
6. Each starter shall have a current transformer and adjustable voltage dropping
resistor(s) to supply a 5.0 VAC signal at full load to the unit control panels.
7. Each starter shall be equipped with a line-to-115 VAC control transformer, fused in
both the primary and secondary, to supply power to the control panels, oil heaters and
oil pumps.
8. Each starter shall include the following:
a) Phase failure and reversal protection
b) Load break disconnect switch
c) Current limiting power fuses
--OR-Across-the-Line type with primary contactor allowing locked rotor amps to reach the motor
when energized.
--OR-Autotransformer type factory wired to the 65% tap with drawout magnetic, three-pole,
vacuum break shorting contactor, drawout magnetic, two-pole, vacuum break starting
contactor, and open delta starting auto-transformer factory set at 65%.
--OR-Primary Reactor type with drawout magnetic, three-pole, vacuum break shorting assembly,
and three-phase starting reactor, factory set at the 65% tap.
All medium and high voltage starters shall have the following components:
84
Catalog WSC/WDC-4
G.
Catalog WSC/WDC-4
Main Control Relays
Redundant motor control relays with coils in parallel and contacts in series to interlock the
starter with the chiller. These two relays shall constitute the only means of energizing the
motor contractors. No other devices (manual or automatic) with the capability of
energizing the starter can be used. The starter is controlled by the unit microprocessor.
Motor Protection and Overloads
The starter shall include overload protection functions. These controls include:
• Solid state overload (overcurrent) protection
• Phase unbalance protection
• Phase reversal and phase loss protection.
• Adjustable overload to closely match motor performance
• Three current transformers to measure motor current and a fourth current transformer
for input to the chiller microprocessor.
Undervoltage (UV) Relay
The undervoltage relay is an adjustable three-phase protection system that is activated
when the voltage falls below a predetermined safe value and is factory set at 85% of
nominal.
Control Voltage Transformer
The starter is provided with a 3KVA control transformer with both secondary and primary
fuses to supply control power to the chiller.
Additional Standard Components
• Mechanical type solderless connectors to handle wire sizes indicated by the NEC.
• Three isolated vertical line contactors
• Three-pole, gang operated non-load break isolating switch
• Three vertically mounted current limiting power fuse blocks (fuses included)
• Magnetic three-pole, vacuum break contactor
• Single phase control circuit transformer
• Vertically mounted control circuit primary current limiting fuses
• Current transformers
• Load terminals
• Control circuit terminal blocks and secondary fuses
• Phase failure and reversal relay
CHILLER CONTROLLER
Base unit/compressor control is done through a 4-by-20-character display to view system
parameters, denote alarms and input setpoints.
In conjunction with the standalone base unit controller, the chiller manufacturer shall
supply a redundant, state-of-the-art Operator Workstation, complete with super VGA
color touchscreen monitor, keyboard and USB port.
The operator workstation shall have inherent trend logging capabilities, which are
transferable to other PC management systems such as an Excel spreadsheet via a USB port.
Active trend logging data shall be available for viewing in 20 minute, 2 hour or 8 hour
intervals. A full 24 hours of history is downloadable via a USB port. The following
trended parameters shall be displayed:
• Entering and leaving chilled water temps
• Entering and leaving condenser water temps
• Evaporator saturated refrigerant pressure
• Condenser saturated refrigerant pressure
• Net oil pressure
• % rated load amps
85
In addition to the trended items above, other real-time operating parameters are also shown
on the touchscreen. These items can be displayed in two ways: by chiller graphic showing
each component or from a color-coded, bar chart format. At a minimum, the following
critical areas must be monitored:
• Oil sump temperature
• Oil feed line temperature
• Evaporator saturated refrigerant temperature
• Suction temperature
• Condenser saturated refrigerant temperature
• Discharge temperature
• Liquid line temperature
Complete unit operating instructions shall be viewable on the touchscreen and be
downloadable via an onboard USB port.
Complete fault history shall be displayed using an easy to decipher, color coded set of
messages that are date and time stamped. The last 20 faults shall be downloadable from
the USB port.
Automatic corrective action to reduce unnecessary cycling shall be accomplished through
pre-emptive control of low evaporator or high discharge pressure conditions to keep the
unit operating through ancillary transient conditions.
System specific, chiller plant architecture software shall be employed to display the chiller,
piping, pumps and cooling tower. Chiller plant optimization software for up to 3 chillers
shall also be included to provide automatic control of: evaporator and condenser pumps
(primary and standby), up to 4 stages of cooling tower fans and a cooling tower modulating
bypass valve and/or cooling tower fan variable frequency drives. There shall be five
possible tower control strategies:
• Tower fan staging only – up to 4 stages controlled by either the entering condenser
water temperature or lift differential temperature between the condenser and
evaporator saturated temperatures.
• Tower fan staging plus low limit - controlled as in # 1 plus tower bypass valve set at a
minimum entering condenser water temperature
• Tower staging with staged bypass control – similar to # 2 with additional control of the
bypass valve between fan staging to smooth control and minimize fan staging.
• VFD staging only – in this mode, a variable speed drive controls the first fan with up
to 3 more fans to be staged on and off and there is no bypass valve.
• VFD and Valve Staging – same as # 4 plus bypass valve control
Factory mounted DDC controllers shall support operation on a BACnet, Modbus or
LONWORKS network a factory-installed communication module.
Factory mounted DDC controller(s) shall support operation on a BACnet®,
Modbus® or LONMARKS ® network via one of the data link / physical layers listed
below as specified by the successful Building Automation System (BAS) supplier.
• BACnet MS/TP master (Clause 9)
• BACnet IP, (Annex J)
• BACnet ISO 8802-3, (Ethernet)
• LONMARKS FTT-10A. The unit controller shall be LONMARKS® certified.
The information communicated between the BAS and the factory mounted unit
controllers shall include the reading and writing of data to allow unit monitoring,
control and alarm notification as specified in the unit sequence of operation and the
unit points list.
86
Catalog WSC/WDC-4
For chillers communicating over a LONMARK network, the corresponding
LONMARK eXternal Interface File (XIF) shall be provided with the chiller submittal
data.
All communication from the chiller unit controller as specified in the points list shall
be via standard BACnet objects. Proprietary BACnet objects shall not be allowed.
BACnet communications shall conform to the BACnet protocol (ANSI/ASHRAE1352001). A BACnet Protocol Implementation Conformance Statement (PICS) shall be
provided along with the unit submittal.
2.5. MISCELLANEOUS ITEMS
A.
Pumpout System: The unit shall be equipped with a pumpout system complete with a
transfer pump, condensing unit, and storage vessel constructed according to ASME Code
for Unfired Pressure Vessels and shall bear the National Board stamp. If the design of the
unit allows the charge to be transferred to and isolated in the main condenser, then a
pumpout system is not required. Transfer of refrigerant charge shall be accomplished by
either main compressor operation, migration, or gravity flow. Isolation shall be
accomplished with valves located at the inlet and outlet of the condenser. The main
condenser shall be sized to contain the refrigerant charge at 90°F according to ANSIASHRAE 15.A.
B.
Purge System (Negative Pressure Chillers Only):
1. The chiller manufacturer shall provide a separate high efficiency purge system that
operates independently of the unit and can be operated while the unit is off. The
system shall consist of an air-cooled condensing unit, purge condensing tank, pumpout
compressor and control system.
2. A dedicated condensing unit shall be provided with the purge system to provide a
cooling source whether or not the chiller is running. The condensing unit shall
provide a low purge coil temperature to result in a maximum loss of 0.1 pounds of
refrigerant per pound of purged air.
3. The purge tank shall consist of a cooling coil, filter-drier cores, water separation tube,
sight glass, drain, and air discharge port. Air and water are separated from the
refrigerant vapor and accumulated in the purge tank.
4. The pumpout system shall consist of a small compressor and a restriction device
located at the pumpout compressor suction connection.
5. The purge unit shall be connected to a 100% reclaim device.
C.
Vacuum Prevention System (negative pressure chillers only): Chiller manufacturer shall
supply and install a vacuum prevention system for each chiller. The system shall
constantly maintain 0.05 psig inside the vessel during non-operational periods. The system
shall consist of a precision pressure controller, two silicon blanket heaters, a pressure
transducer, and solid-state safety circuit.
D.
Refrigerant Detection Device (negative pressure chillers only): Chiller manufacturer shall
supply and install a refrigerant detection device and alarm capable of monitoring
refrigerant at a level of 10 ppm. Due to the critical nature of this device and possible
owner liability, the chiller manufacturer shall guarantee and maintain the detection monitor
for five years after owner acceptance of the system.
E.
Waffle type vibration pads for field mounting under unit feet.
PART 3 — EXECUTION
3.1 INSTALLATION
A.
Install according to manufacturer’s requirements, shop drawings, and Contract Documents.
B.
Adjust chiller alignment on concrete foundations, sole plates or subbases as called for on
drawings.
C.
Arrange the piping on each vessel to allow for dismantling the pipe to permit head removal
and tube cleaning.
D.
Furnish and install necessary auxiliary water piping for oil cooler.
E.
Coordinate electrical installation with electrical contractor.
Catalog WSC/WDC-4
87
F.
G.
3.2 START-UP
A.
B.
88
Coordinate controls with control contractor.
Provide all materiel required to ensure a fully operational and functional chiller.
Units shall be factory charged with the proper refrigerant and oil.
Factory Start-Up Services: Provide for as long a time as is necessary to ensure proper
operation of the unit, but in no case for less than two full working days. During the period
of start-up, the Start-up Technician shall instruct the Owner’s representative in proper care
and operation of the unit.
Catalog WSC/WDC-4
SECTION 15XXX
CENTRIFUGAL CHILLERS
DUAL COMPRESSOR
PART 1 — GENERAL
1.1 SUMMARY
Section includes design, performance criteria, refrigerants, controls, and installation requirements for
water-cooled centrifugal chillers.
1.02 REFERENCES
Comply with the following codes and standards
ARI 550/590
NEC
ANSI/ASHRAE 15
OSHA as adopted by the State
ASME Section VIII
1.3 SUBMITTALS
Submittals shall include the following:
A.
Dimensioned plan and elevation view Drawings, including motor starter cabinet, required
clearances, and location of all field piping and electrical connections.
B.
Summaries of all auxiliary utility requirements such as: electricity, water, air, etc.
Summary shall indicate quality and quantity of each required utility.
C.
Diagram of control system indicating points for field interface and field connection.
Diagram shall fully depict field and factory wiring.
D.
Manufacturer’s certified performance data at full load plus IPLV or NPLV.
E
Installation and Operating Manuals.
1.4 QUALITY ASSURANCE
A.
Qualifications: Equipment manufacturer must specialize in the manufacture of the
products specified and have five years experience with the equipment and refrigerant
offered.
B.
Regulatory Requirements: Comply with the codes and standards in Section 1.2.
C.
Chiller manufacturer plant shall be ISO Registered.
1.5
DELIVERY AND HANDLING
A.
Chillers shall be delivered to the job site completely assembled and charged with
refrigerant and oil.
B.
Comply with the manufacturer’s instructions for rigging and transporting units. Leave
protective covers in place until installation.
1.6
WARRANTY
The refrigeration equipment manufacturer’s warranty shall be for a period of (one) -- Or -- (two) -Or-- (five) years from date of equipment start or 18 months from shipment whichever occurs first.
The warranty shall include parts and labor costs for the repair or replacement of defects in material
or workmanship. The refrigerant charge shall be warranted against contamination from a motor
burnout for five years.
1.7
MAINTENANCE
Maintenance of the chillers shall be the responsibility of the owner with the following exceptions:
A.
The manufacturer shall provide the first year scheduled oil and filter change if required.
B.
The manufacturer shall provide first year purge unit maintenance if required.
PART 2 — PRODUCTS
2.1
ACCEPTABLE MANUFACTURERS
A. McQuay International
B. (Approved Equal)
2.2
UNIT DESCRIPTION
Catalog WSC/WDC-4
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2.3
Provide and install as shown on the plans a factory assembled, charged, and run-tested water-cooled
packaged chiller. Each unit shall be complete with two single-stage hermetic centrifugal
compressors each having independent lubrication and control systems, factory mounted starters, and
isolation valves. The evaporator, condenser, and refrigerant control device of each unit shall be
common to the compressors. The chiller unit shall be capable of running on one compressor with
the other compressor or any of its auxiliaries removed.
DESIGN REQUIREMENTS
A.
General: Provide a complete water-cooled dual hermetic compressor centrifugal water
chiller as specified herein. Machine shall be provided according to standards, Section 1.2.
In general, unit shall consist of two compressors, refrigerant condenser and evaporator, two
lubrication systems, two starters and two control systems.
Note: Chillers shall be charged with a refrigerant such as HFC-134a, not subject to the
Montreal Protocol and the U. S. Clean Air Act.
B.
Performance: Refer to schedule on the drawings. The chiller shall be capable of stable
operation to five percent of full load with standard ARI entering condensing water relief
without hot gas bypass.
C.
Acoustics: Sound pressure for the unit shall not exceed the following specified levels.
Provide the necessary acoustic treatment to chiller as required. Sound data shall be
measured according to ARI Standard 575-87and shall be in dB. Data shall be the highest
levels recorded at all load points. Test shall be in accordance with ARI Standard 575.
Octave Band
63
125
250
500
1000
2000
4000
8000
dba
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____
____
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2.4 CHILLER COMPONENTS
A.
Compressors:
1.
Unit shall have two single-stage hermetic centrifugal compressors. Casing design
shall ensure major wearing parts, main bearings and thrust bearings are accessible for
maintenance and replacement. Lubrication system shall protect machine during coast
down resulting from a loss of power.
2.
Impeller shall be statically and dynamically balanced. The compressor shall be
vibration tested and not exceed 0.14 IPS.
3.
Movable inlet guide vanes actuated by an internal oil pressure driven piston shall
accomplish unloading. Compressors using an unloading system that requires
penetrations of the compressor housing or linkages, or both, that must be lubricated
and adjusted are acceptable provided the manufacturer provides a five-year inspection
agreement consisting of semi-annual inspection, lubrication, and annual changeout of
compressor seals. A statement of inclusion must accompany any quotations.
4.
If compressors are not equipped with guide vanes for each stage and movable
discharge diffusers, then furnish hot gas bypass and select chillers at 5% lower kW/ton
than specified to compensate for bypass inefficiency at low loads.
B.
Lubrication System: Each compressor shall have an independent lubrication system to
provide lubrication to all parts requiring oil. Provide a heater in the oil sump to maintain
oil at sufficient temperature to minimize affinity of refrigerant, and a thermostatically
controlled water-cooled oil cooler. Coolers located inside the evaporator or condenser are
not acceptable due to inaccessibility. A positive displacement submerged oil pump shall be
powered through the unit control transformer.
C.
Refrigerant Evaporator and Condenser:
1.
90
Evaporator and condenser shall be of the shell-and-tube type, designed,
constructed, tested and stamped according to the requirements of the ASME Code,
Section VIII. Regardless of the operating pressure, the refrigerant side of each
vessel will bear the ASME stamp indicating compliance with the code and
indicating a test pressure of 1.3 times the working pressure but not less than 100
psig. Provide intermediate tube supports at a maximum of 18 inch spacing.
Catalog WSC/WDC-4
2.
D.
E.
Catalog WSC/WDC-4
Tubes shall be enhanced for maximum heat transfer, rolled into steel tube sheets
and sealed with Locktite or equal sealer. The tubes shall be individually
replaceable and secured to the intermediate supports without rolling.
3.
Provide sufficient isolation valves and condenser volume to hold full refrigerant
charge in the condenser during servicing or provide a separate pumpout system and
storage tank sufficient to hold the charge of the largest unit being furnished.
4.
The water sides shall be designed for a minimum of 150 psig or as specified
elsewhere. Vents and drains shall be provided.
5.
Chilled water minimum refrigerant temperature shall be 33°F.
6.
An electronic or thermal refrigerant expansion valve shall control refrigerant flow
to the evaporator. Fixed orifice devices or float controls with hot gas bypass are
not acceptable because of inefficient control at low load conditions. The liquid
line shall have a moisture indicating sight glass.
7.
The evaporator and condenser shall be separate shells. A single shell containing
both vessel functions is not acceptable because of the possibility of internal leaks.
8.
Interstage economizers shall be used between each compressor stage for increased
efficiency.
9.
Reseating type spring loaded pressure relief valves according to ASHRAE-15
safety code shall be furnished. The evaporator shall be provided with single or
multiple valves. The condenser shall be provided with dual relief valves equipped
with a transfer valve so one valve can be removed for testing or replacement
without loss of refrigerant or removal of refrigerant from the vessel. Rupture disks
are not acceptable.
10.
The evaporator, suction line, and any other component or part of a component
subject to condensing moisture shall be insulated with UL recognized 3/4 inch
closed cell insulation. All joints and seams shall be carefully sealed to form a
vapor barrier.
11.
Provide Factory-mounted thermal dispersion flow switches on each vessel to
prevent unit operation with no flow, furnished, installed and wired by the
contractor.
Prime Mover: Squirrel cage induction motor of the hermetic type of sufficient size to
efficiently fulfill compressor horsepower requirements. Motor shall be liquid refrigerant
cooled with internal thermal overload protection devices embedded in the winding of each
phase. Motor shall be compatible with the starting method specified hereinafter. If the
Contractor chooses to provided an open drive motor or compressor, verify in the submittal
that the scheduled chiller room ventilation system will accommodate the additional heat
and maintain the equipment room at design indoor temperature based on 95°F outdoor
ambient ventilation air available.
If additional cooling is required, manufacturer shall be responsible for the installation,
wiring and controls of a cooling system. Chiller selection shall compensate for tons and
efficiency loss to make certain the owner is not penalized.
Motor Starters:
1.
The main motor starters are to be factory mounted and fully wired to the chiller
components and factory tested during the run test of the unit.
-- OR -The main motor starters are to be furnished by the chiller manufacturer and
shipped loose for floor mounting and field wiring to the chiller package. They
shall be free-standing with NEMA-1 enclosure designed for top entry and bottom
exit and with front access.
2.
For air-cooled motors the chiller manufacturer shall be responsible for providing
the cooling of the refrigeration machinery room. The sensible cooling load shall
be based on the total heat rejection to the atmosphere from tow refrigeration units.
3.
For open motor unit, an oil reservoir shall collect any oil and refrigerant that leaks
past the seal. A float device shall be provided to open when the reservoir is full,
directing the refrigerant/oil mixture back into the compressor housing.
91
F.
92
Manufacturer shall warrant the shaft seal, reservoir, and float valve system against
leakage of oil and refrigerant to the outside of the refrigerating unit for a period of
5 years from the initial start-up including parts and labor to replace a defective
seal and any refrigerant required to trim the charge original specifications.
4.
The starters must comply with Section 1.2 as required.
Low Voltage (200 through 600 volts) controllers are to be continuous duty AC
5.
magnetic type constructed according to NEMA standards for Industrial Controls
and Systems (ICS) and capable of carrying the specified current on a continuous
basis. The starters shall be:
Autotransformer - The autotransformer starters shall be of the closed transition
type and equipped with multiple taps for 80%, 65%, 50%, and set up for the 65%
tap. A clearly marked timer shall be adjustable from 0 to 30 seconds.
-- OR -Wye-Delta Closed Transition - The wye contactor shall be capable of handling
33% of the delta locked rotor current and be equipped with properly sized
resistors to provide a smooth transition. The resistors shall be protected with a
transition resistor protector, tripping in a maximum of two seconds, locking out
the starter, and shall be manually reset. A clearly marked transition timer shall be
adjustable from 0 to 30 seconds.
-- OR -Solid-State Reduced Voltage - Starter shall be furnished with silicon controlled
rectifiers (SCR) connected for starting and include a bypass contactor. When
operating speed is reached, the bypass contactor shall be energized removing the
SCRs from the circuit during normal running.
All Low Voltage starters shall:
6.
Be coordinated with the chiller package(s) making certain all terminals are
properly marked according to the chiller manufacturer’s wiring diagrams.
7.
The starters shall be equipped with redundant motor control relays (MCR) with
coils in parallel. The relays interconnect the starters with the unit control panels
and directly operate the main motor contactors. The MCRs shall constitute the
only means of energizing the motor contacts.
8.
The main contactors shall have a normally open and a normally closed auxiliary
contact rated at 125VA pilot duty at 115 VAC. An additional set of normally open
contacts shall be provided for each MCR.
9.
There shall be electronic overloads in each phase set at 107% of the rated load
amps of each motor. Overloads shall be manual reset and shall de-energize the
main contactors when the overcurrent occurs. The overloads shall be adjustable
and selected for mid-range. Overloads shall be adjusted for a locked rotor trip
time of 8 seconds at full voltage and must trip in 60 seconds or less at reduced
voltage (33% of delta LRA).
10.
Each starter shall have a current transformer and adjustable voltage dropping
resistor(s) to supply a 5.0 VAC signal at full load to the unit control panels.
11.
Each starter shall be equipped with a line to 115 VAC control transformer, fused
in both the primary and secondary, to supply power to the control panels, oil
heaters and oil pumps.
12.
Each starter shall include the following protective devices:
a) Phase failure and reversal protection
b) Stall protection
-ORVariable Frequency Drive
1.
The chiller shall be equipped with a Variable Frequency Drive (VFD) to
automatically regulate each compressor speed in response to cooling load and
compressor pressure lift. The chiller control shall coordinate compressor speed
and guide vane position to optimize chiller efficiency.
Catalog WSC/WDC-4
2.
3.
A digital regulator shall provide V/Hz control.
The VFD shall have 110% continuous overload of continuous amp rating with no
time limit, PWM (pulse width modulated) output, IGBT (insulated gate bipolar
transistors) power technology, full power rating at 2kHz, DC bus inductor
(choke), and wireless construction.
4.
Units 273 amps and below shall be air-cooled, units above 274 amps shall be
water-cooled. All heat producing devices shall be contained in a single heatsink
with single inlet and out connections for the connection of chilled water. When
factory mounted on the chiller package, the water connections shall be piped and
leak tested at the factory.
Medium Voltage (601 through 5000 volts) and High Voltage (5001 through 7200 volts).
The starter shall be:
Solid-State Reduced Voltage - Starter shall be furnished with silicon controlled
rectifiers (SCR) connected for starting and include a bypass contactor. When
operating speed is reached, the bypass contactor shall be energized removing the
SCRs from the circuit during normal running.
1.
The starter shall be coordinated with the chiller package(s) making certain
all terminals are properly marked according to the chiller manufacturer’s
wiring diagrams.
2.
The starters shall be equipped with redundant motor control relays (MCR)
with coils in parallel. The relays interconnect the starters with the unit
control panels and directly operate the main motor contactors. The MCRs
shall constitute the only means of energizing the motor contacts.
3.
The main contactors shall have a normally open and a normally closed
auxiliary contact rated at 125VA pilot duty at 115 VAC. An additional set
of normally open contacts shall be provided for each MCR.
4.
There shall be electronic overloads in each phase set at 107% of the rated
load amps of each motor. Overloads shall be manual reset and shall deenergize the main contactors when the overcurrent occurs. The overloads
shall be adjustable and selected for mid-range. Overloads shall be adjusted
for a locked rotor trip time of 8 seconds at full voltage and must trip in 60
seconds or less at reduced voltage (33% of delta LRA).
5.
Each starter shall have a current transformer and adjustable voltage
dropping resistor(s) to supply a 5.0 VAC signal at full load to the unit
control panels.
6.
Each starter shall be equipped with a line-to-115 VAC control transformer,
fused in both the primary and secondary, to supply power to the control
panels, oil heaters and oil pumps.
7.
Each starter shall include the following:
8.
Phase failure and reversal protection
9.
Load break disconnect switch
10.
Current limiting power fuses
--OR-Across-the-Line type with primary contactor allowing locked rotor amps to reach the motor
when energized.
--OR-Autotransformer type factory wired to the 65% tap with drawout magnetic, three-pole,
vacuum break shorting contactor, drawout magnetic, two-pole, vacuum break starting
contactor, and open delta starting auto-transformer factory set at 65%.
--OR-Primary Reactor type with drawout magnetic, three-pole, vacuum break shorting assembly,
and three-phase starting reactor, factory set at the 65% tap.
All medium and high voltage starters shall have the following components:
Main Control Relays
Catalog WSC/WDC-4
93
G.
94
Redundant motor control relays with coils in parallel and contacts in series to interlock the
starter with the chiller. These two relays shall constitute the only means of energizing the
motor contractors. No other devices (manual or automatic) with the capability of energizing
the starter can be used. The starter is controlled by the unit microprocessor.
Motor Protection and Overloads
The starter shall include overload protection functions. These controls include:
• Solid state overload (overcurrent) protection
• Phase unbalance protection
• Phase reversal and phase loss protection.
• Adjustable overload to closely match motor performance
• Three current transformers to measure motor current and a fourth current transformer
for input to the chiller microprocessor.
Undervoltage (UV) Relay
The undervoltage relay is an adjustable three-phase protection system that is activated
when the voltage falls below a predetermined safe value and is factory set at 85% of
nominal.
Control Voltage Transformer
The starter is provided with a 3KVA control transformer with both secondary and primary
fuses to supply control power to the chiller.
Additional Standard Components
•
Mechanical type solderless connectors to handle wire sizes indicated by the NEC.
•
Three isolated vertical line contactors
•
Three-pole, gang operated non-load break isolating switch
•
Three vertically mounted current limiting power fuse blocks (fuses included)
•
Magnetic three-pole, vacuum break contactor
•
Single phase control circuit transformer
•
Vertically mounted control circuit primary current limiting fuses
•
Current transformers
•
Load terminals
•
Control circuit terminal blocks and secondary fuses
•
Phase failure and reversal relay
CHILLER CONTROLLER
Base unit/compressor control is done through a 4-by-20-character display to view system
parameters, denote alarms and input setpoints.
In conjunction with the standalone base unit controller, the chiller manufacturer shall
supply a redundant, state-of-the-art Operator Workstation, complete with super VGA color
touchscreen monitor, keyboard and USB port.
The operator workstation shall be common for both compressors and have inherent trend
logging capabilities, which are transferable to other PC management systems such as an
Excel spread sheet via a USB port. Active trend logging data shall be available for
viewing in 20 minute, 2 hour or 8 hour intervals. A full 24 hours of history is
downloadable via diskette. The following trended parameters shall be displayed:
• Entering and leaving chilled water temps
• Entering and leaving condenser water temps
• Evaporator saturated refrigerant pressure
• Condenser saturated refrigerant pressure
• Net oil pressure for each compressor
• % rated load amps for entire unit
In addition to the trended items above, other real-time operating parameters are also shown
on the touchscreen. These items can be displayed in two ways: by chiller graphic showing
Catalog WSC/WDC-4
each component or from a color-coded, bar chart format. At a minimum, the following
critical areas must be monitored:
• Oil sump temperature per compressor
• Oil feed line temperature per compressor
• Evaporator saturated refrigerant temperature for unit
• Suction temperature for unit
• Condenser saturated refrigerant temperature for unit
• Discharge temperature for unit
• Liquid line temperature for unit
The unit operating and maintenance instructions shall be viewable on the touchscreen and
downloadable via an onboard USB port.
Complete fault history shall be displayed using an easy to decipher, color coded set of
messages that are date and time stamped. The last 20 faults shall be downloadable from
the USB port.
Automatic corrective action to reduce unnecessary cycling shall be accomplished through
pre-emptive control of low evaporator or high discharge pressure conditions to keep the
unit operating through ancillary transient conditions.
System specific, chiller plant architecture software shall be employed to display the chiller,
piping, pumps and cooling tower. Chiller plant optimization software for up to 4 chillers
shall also be included to provide automatic control of: evaporator and condenser pumps
(primary and standby), up to 4 stages of cooling tower fans and a cooling tower modulating
bypass valve or cooling tower variable frequency drives. There shall be five possible tower
control strategies:
• Tower fan staging only – up to 4 stages controlled by either the entering condenser
water temperature or lift differential temperature between the condenser and
evaporator saturated temperatures.
• Tower fan staging plus low limit - controlled as in # 1 plus tower bypass valve set at a
minimum entering condenser water temperature.
• Tower staging with staged bypass control – similar to # 2 with additional control of the
bypass valve between fan staging to smooth control and minimize fan staging.
• VFD staging only – in this mode, a variable speed drive controls the first fan with up
to 3 more fans to be staged on and off and there is no bypass valve.
• VFD and Valve Staging – same as # 4 plus bypass valve control.
Factory mounted DDC controllers shall support operation on a BACnet, Modbus or
LONWORKS network via a factory-installed communication module.
Factory mounted DDC controller(s) shall support operation on a BACnet®, Modbus® or
LONMARKS ® network via one of the data link / physical layers listed below as specified
by the successful Building Automation System (BAS) supplier.
•
•
•
•
BACnet MS/TP master (Clause 9)
BACnet IP, (Annex J)
BACnet ISO 8802-3, (Ethernet)
LONMARKS FTT-10A. The unit controller shall be LONMARKS®
certified.
The information communicated between the BAS and the factory mounted unit controllers
shall include the reading and writing of data to allow unit monitoring, control and alarm
notification as specified in the unit sequence of operation and the unit points list.
For chillers communicating over a LONMARK network, the corresponding LONMARK
eXternal Interface File (XIF) shall be provided with the chiller submittal data.
All communication from the chiller unit controller as specified in the points list shall be via
standard BACnet objects. Proprietary BACnet objects shall not be allowed. BACnet
communications shall conform to the BACnet protocol (ANSI/ASHRAE135-2001). A
BACnet Protocol Implementation Conformance Statement (PICS) shall be provided along
with the unit submittal.
Catalog WSC/WDC-4
95
2.5.
MISCELLANEOUS ITEMS
A.
Pumpout System: The unit shall be equipped with a pumpout system complete with a
transfer pump, condensing unit, and storage vessel constructed according to ASME Code
for Unfired Pressure Vessels and shall bear the National Boards stamp. If the design of the
unit allows the charge to be transferred to and isolated in the main condenser, then a
pumpout system is not required. Transfer of refrigerant charge shall be accomplished by
either main compressor operation, migration, or gravity flow. Isolation shall be
accomplished with valves located at the inlet and exit of the condenser. The main
condenser shall be sized to contain the refrigerant charge at 90°F according to ANSIASHRAE 15.A.
B.
Purge System (negative pressure chillers only):
1. The chiller manufacturer shall provide a separate high efficiency purge system that
operates independently of the unit and can be operated while the unit is off. The
system shall consist of an air-cooled condensing unit, purge condensing tank, pumpout
compressor and control system.
2. A dedicated condensing unit shall be provided with the purge system to provide a
cooling source whether or not the chiller is running. The condensing unit shall
provide a low purge coil temperature to result in a maximum loss of 0.1 pounds of
refrigerant per pound of purged air.
3. The purge tank shall consist of a cooling coil, filter-drier, water separation tube, sight
glass, drain, and air discharge port. Air and water are separated from the refrigerant
vapor and accumulated in the purge tank.
4. The pumpout system shall consist of a small compressor and a restriction device
located at the pumpout compressor suction connection.
5. The purge unit shall be connected to a 100% reclaim device.
C.
Vacuum Prevention System (Negative pressure chillers only): Chiller manufacturer shall
supply and install a vacuum prevention system for each chiller. The system shall
constantly maintain 0.05 psig inside the vessel during non-operational periods. The system
shall consist of a precision pressure controller, two silicon blanket heaters, a pressure
transducer, and solid-state safety circuit.
D.
Refrigerant Detection Device (negative pressure chillers only): Chiller manufacturer shall
supply and install a refrigerant detection device and alarm capable of monitoring
refrigerant at a level of 10 ppm. Due to the critical nature of this device and possible
owner liability, the chiller manufacturer shall guarantee and maintain the detection monitor
for five years after owner acceptance of the system.
E.
Waffle type vibration pads for field mounting under unit feet.
PART 3 — EXECUTION
3.1
INSTALLATION
A.
Install per manufacturer’s requirements, shop drawings, and Contract Documents.
B.
Adjust chiller alignment on foundations, or subbases as called for on drawings.
C.
Arrange piping to allow for dismantling to permit head removal and tube cleaning.
D.
Furnish and install necessary auxiliary water piping for oil cooler.
E.
Coordinate electrical installation with electrical contractor.
F.
Coordinate controls with control contractor.
G.
Provide all materiel required for a fully operational and functional chiller.
3.2
START-UP
A.
Units shall be factory charged with the proper refrigerant and oil.
B.
Factory Start-Up Services: Provide for as long a time as is necessary to ensure proper
operation of the unit, but in no case for less than two full working days. During the period
of start-up, The Start-up Technician shall instruct the Owner’s representative in proper care
and operation of the unit.
96
Catalog WSC/WDC-4
Catalog WSC/WDC-4
97
98
Catalog WSC/WDC-4
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.
Post Office Box 2510, Staunton, Virginia 24402 • (800) 432-1342 • www.mcquay.com
Catalog WSCWDC-4 (9/05)
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