Question 21Refrigeration & AC - Assistant Engineer

The correct answer is D) The expansion valve would hunt excessively, alternately starving and overfeeding the evaporator coil. This is because an oversized valve cage assembly (5 tons) compared to the original (1/2 ton) would cause the expansion valve to be unable to properly regulate the flow of refrigerant to the evaporator. The excessive capacity of the replacement valve would cause it to alternate between starving and overfeeding the evaporator, leading to inconsistent superheat levels and the expansion valve "hunting" - rapidly adjusting in an attempt to maintain proper superheat. This would result in unstable operation and potential equipment damage over time. The other answer choices are incorrect because: A) the evaporator would not be consistently underfeeding, and B) the expansion valve would not function normally with such a mismatch in capacity. C) is also incorrect, as the evaporator would not consistently overheat but rather experience fluctuating superheat levels.