An epic battle will be happening across Chicago. Outdoor Refrigeration Units will be fighting the elements to maintain proper temperature.
A Polar Vortex is making it’s way towards Chicago. We will experience some of the coldest weather in decades. Predicted temperatures for Monday are -12F & -40F windchill. Countless refrigeration systems will fail to maintain proper temperature. Most of these affected systems will have the compressor unit located outside. Outdoor commercial refrigeration condenser units located in regions that experience cold Winters must have low ambient operation controls. Units not designed to run in cold weather will not maintain proper temperature in the conditioned space when it gets cold out. The following are some of the different types of components that are needed to help a refrigeration unit run in cold weather.
Cold Weather Accessories & Controls
- Condenser Bypass Valve
- Condenser Fan Cycling Control
- Compressor Crank Case Heater
- Adjustable Low Pressure Control
The condenser bypass valve is used to used divert refrigerant from the condenser coil & instead pipe it right into the liquid line to maintain sufficient head pressure. This low ambient control works in any weather condition including subzero windy weather. This is the best cold weather control for your commercial refrigeration unit.
The condenser fan cycling control is used to cycle outdoor condenser fan motor on & off to try & maintain system head pressure. This method may not work well in extreme cold & windy conditions. This is especially true when the condenser coil has been installed facing West. Often wind travels West to East & can over cool the condenser even with the fan cycled off. This mostly happens on extremely cold & windy days. This is why we do not believe that a condenser fan cycling control is a good choice. There may be several days a year where a cooler or freezer will not operate correctly with a condenser fan cycling control.
The compressor crank case heater is used to prevent liquid refrigerant from migrating into compressor. The heater is energized all the time & keeps the compressor warm. This protects the compressor from liquid migration & liquid slugging.
All outdoor condensing units should have an adjustable low pressure control. Some units come with OEM nonadjustable low pressure controls that have a settings too high for cold ambient conditions. This may cause compressor to sit idle & not cool the space to be conditioned when it gets cold out. We recommend a standard pump down setting for all outdoor compressor units. The standard pump down setting is 20# low side compressor on & 0# low side compressor off.
Owners of commercial refrigeration systems in Chicago should keep a close eye on temperature & cycling during the extreme weather created by the Polar Vortex. If temperatures become erratic & warm up during the cold snap, chances are there is a problem with winter operation.
Please feel free to comment on this post or ask questions below. We are here for commercial refrigeration repair service during this weather & as always we are available 24/7/365.
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