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 in a multi-box refrigeration plant are actively feeding liquid refrigerant, maximum suction pressure is maintained, resulting in the highest control oil pressure acting on the hydraulic relay unloader piston.