As shown in the illustrated LP centrifugal chiller high efficiency purge recovery unit piping schematic, what statement is true concerning the vacuum pump? See Illustration GS-RA-55 Illustration GS-RA-55: the U.S. Coast Guard has not released this illustration.

Correct Answer: Option A — The vacuum pump is designed to remove refrigerant vapor from the carbon filter tank and transfer these vapors to the evaporator to minimize the loss of refrigerant to the atmosphere.

The vacuum pump in a low-pressure centrifugal chiller purge unit recovers refrigerant vapors from the carbon filter tank. By transferring these vapors back to the evaporator, the system minimizes environmental release of refrigerant, complying with EPA and maritime regulations regarding the containment of ozone-depleting substances.