Question 70Refrigeration & AC - 1st Asst/Chief

The correct answer is A) leaky suction valves. In a reciprocating compressor, low discharge head pressure is commonly caused by leaky suction valves. When the suction valves are not sealing properly, it allows refrigerant to leak back into the suction side of the compressor, reducing the compressor's ability to build up discharge pressure. This results in lower than normal discharge head pressure. The other options are incorrect because: B) insufficient cooling water to the condenser would cause high discharge pressure, not low; C) air in the condenser would also cause high discharge pressure; and D) air in the evaporator coils would not directly affect the discharge head pressure of the compressor.