Crankcase Pressure Regulating Valves

Crankcase Pressure Regulating Valves

In orden to limit the power requirement of the compressor to the allowable operating limit, a crankcase pressure regulating valve may be necessary. This most frequently occurs on low temperature compressors where the power requirement during pulldown periods or after defrost may be greatly in excess of the compressor motor's capabilities. Copeland compressors should not be operated at suction pressure in excess of the published limits on compressor specification sheets without approval of the copeland application Engineering Department.

Since any pressure drop in the compressor suctio line lowers the system capacity, the CPR valve should be sized for a minimum pressure drop. In order to restric pull down capacity as little as possible, the valve setting should be as high as the motor power requirement will allow.

thermal expancsion valves of the pressure limiting type are not recommended when a CPR valve is used, particularly if the pressure settings are fairly close. particularly if the pressure settings are fairly close, because of the possibility of the action of the two valves coming in conflict in their response to system pressures.