As shown in the illustrated LP centrifugal chiller pressure maintenance system, what is its functional purpose? Illustration GS-RA-40 Illustration GS-RA-40: the U.S. Coast Guard has not released this illustration.

Correct Answer: Option C — prevent the entrance of air into the chiller when the chiller is idle

Low-pressure centrifugal chillers operate below atmospheric pressure at idle or low loads. The pressure maintenance system introduces a small positive pressure or refrigerant gas blanket to prevent atmospheric air and moisture ingress, avoiding contamination.