During operating periods of a multi-box refrigeration system using a capacity controlled compressor, when all of the evaporators of a four box plant are actively being fed with liquid refrigerant, the control oil pressure acting on the hydraulic relay piston will be at what value? Illustration GS-RA-13

Illustration GS-RA-13: the U.S. Coast Guard has not released this illustration.

Question

During operating periods of a multi-box refrigeration system using a capacity controlled compressor, when all of the evaporators of a four box plant are actively being fed with liquid refrigerant, the control oil pressure acting on the hydraulic relay piston will be at what value? Illustration GS-RA-13

Illustration GS-RA-13: the U.S. Coast Guard has not released this illustration.

Accepted Answer

Option C: the highest. When all evaporators demand cooling, suction pressures remain high, maximizing control oil pressure acting on the hydraulic unloader piston to maintain full compressor cylinder loading.