Specifications

Catalog WSC/WDC-4 5
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 WSC – Single compressor chiller
Cooling, most hours at part load WDC – Dual compressor chiller
Heating application TSC – Templifier water heater
Simultaneous cooling and heating HSC – Heat recovery chillers
Optimized part load performance 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!