Question 80Refrigeration & AC - QMED

The correct answer is C) excessive amount of non-condensable gases trapped in the condenser. If increasing the cooling water flow to a refrigeration condenser fails to lower the condenser pressure, the probable cause is likely due to an excessive amount of non-condensable gases trapped in the condenser. Non-condensable gases, such as air, reduce the condenser's heat transfer efficiency, preventing the refrigerant from condensing properly and resulting in higher condenser pressure. The other options are incorrect because a low level of Freon (A) would generally result in low system pressure, a partially blocked thermal expansion valve (B) would affect the evaporator rather than the condenser, and an evaporator coil in need of defrosting (D) would not directly impact the condenser pressure.