Crankcase Pressure Regulating Valves are designed to prevent overloading of the compressor motor by limiting the crankcase pressure to a predetermined maximum value during and after a defrost cycle or a normal shut-down period. These valves automatically throttle the vapour flow from the evaporator until the compressor can handle the load.

Sporlan manufactures five adjustable models... CRO-4, CRO-6, CROT-6, CRO-10 and CROT-10 all models respond only to their outlet pressure and modulate to prevent the suction pressure at the compressor from rising above the valve setting. Since these valves are adjustable, the setting may be altered to suit the specific system requirements.
 
 
 

The ratings for these valves vary depending on three items: design suction pressure after pulldown, maximum allowable suction pressure recommended by the compressor or unit manufacturer (this is the valve setting), and pressure drop across the valve. The difference between the design suction pressure and the valve setting determines how much of the valve stroke is used. Therefore, the valve setting should be kept as high as possible without exceeding the recommendation of the compressor or unit manufacturer. Once this information is available, the correct CRO can be selected from the data below.

Connections - (Standard Connections are in BOLD type).
CRO-4 - 3/8", 1/2" ODF Solder and 3/8", 1/2" SAE Flare
CRO-6, *CROT-6 - 5/8", 7/8", 1-1/8" ODF Solder and 1/2",
5/8", 3/4" SAE Flare.
CRO-10, *CROT-10 - 7/8", 1-1/8", 1-3/8" ODF Solder.

* "T" indicates access valve on inlet connection.