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? Illustration 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? Illustration 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 over feeding the evaporator coil.. Installing an excessively oversized thermostatic expansion valve severely disrupts the mass flow equilibrium of the refrigeration cycle. The valve responds too drastically to load changes, causing hunting where it alternately floods and starves the evaporator.