How cold weather affects outdoor refrigeration units.

Winter in Chicago can be tough on outdoor commercial refrigeration equipment. Refrigeration compressor units that are installed outdoors must have cold weather controls to operate properly and maintain proper temperature in the cooler or freezer during the cold winter season.

When it gets cold out the refrigerant pressures will drop too low due to the cold air passing through the condenser coil. When this happens the space being conditioned will no longer maintain the proper temperature. A compressor unit without proper low ambient temperature controls may sit idle and not even turn on due to low pressure.  Don’t worry if this happens to you – Northeast Cooling can help keep your equipment running well this winter.

One way to maintain proper head pressure on an outdoor unit in cold weather is by using a fan cycling control. This control reads the head pressure of the system by connecting it to the high pressure refrigerant line. It makes and breaks power to the condenser fan motor to maintain a certain pressure.

Here is an example setting for R22 gas: Fan cycle setting 260# of pressure turns fan on.  230# of pressure turns fan off.

By keeping the head pressure above 200# the fan cycle control avoids a warm refrigeration unit during cold weather. This works well in most situations,but not all. A fan cycle control will not work well in sub zero windy weather. When it is very cold and windy out the pressures can still drop too low even if the condenser fan remains off. Extremely cold air can cause the refrigerant pressure to drop too low simply by blowing through the condenser coil.

Another way to maintain proper pressures in cold weather is by using a bypass valve. This valve lets refrigerant bypass the condenser coil when the pressures drop below a certain level. The dome on the bypass valve is charged with nitrogen. This gas does not change pressure based on temperature. That is why it is used to control the opening and closing of the bypass valve. When it is cold and the bypass valve senses a head pressure drop it lets the gas bypass going through the condenser coil and diverts it straight into the system liquid line. This set up works better for areas that are extremely cold and windy all winter.

When it gets cold this winter monitor your refrigeration equipment temperature, especially if the compressor unit is outdoors. If you notice your box warming up on cold days chances are it doesn’t have proper winter controls. This can end up damaging the compressor and other components within the system.

Northeast Cooling specializes in all types of commercial refrigeration and can help keep your equipment running well this winter.

Contact us for a quote on winter controlls to protect your equipment and your product!

Google+ Comments