Question 163Refrigeration & AC - Assistant Engineer

The correct answer is C) leaky suction valves. In a reciprocating compressor air conditioning system, low discharge head pressure can be caused by leaky suction valves. Leaky suction valves allow refrigerant to flow back from the discharge side to the suction side, reducing the overall compression and discharge pressure of the system. The other answer choices are incorrect because: A) insufficient cooling water to the condenser would cause high discharge pressure, not low; B) air in the evaporator coils would cause low suction pressure, not low discharge pressure; and D) air in the condenser would also cause high discharge pressure, not low.