If the needle and seat assembly is excessively eroded, the valve cage assembly can be replaced. In replacing the original valve cage assembly rated at 1/2 tons, what would be the result if the replacement valve cage was oversized at 5 tons? GS-RA-07

Illustration GS-RA-07: the U.S. Coast Guard has not released this illustration.

Question

If the needle and seat assembly is excessively eroded, the valve cage assembly can be replaced. In replacing the original valve cage assembly rated at 1/2 tons, what would be the result if the replacement valve cage was oversized at 5 tons? GS-RA-07

Illustration GS-RA-07: the U.S. Coast Guard has not released this illustration.

Accepted Answer

Option A: The expansion valve would hunt excessively, alternately starving and overfeeding the evaporator coil.. An oversized valve cage supplies excessive mass flow instantly, causing the evaporator to flood, dropping superheat, and forcing the valve to hunt between extreme starving and overfeeding conditions.