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 D: The expansion valve would hunt excessively, alternately starving and overfeeding the evaporator coil.. Installing an excessively oversized valve cage vastly increases orifice area beyond design parameters. The valve instantly floods the evaporator, starves as pressure drops, and continuously cycles between extremes, resulting in severe hunting that destabilizes the refrigeration cycle.