Question 69Refrigeration & AC - 1st Asst/Chief

The correct answer is D) The low pressure control contacts are stuck open. The key indicators in the problem statement are the high suction pressure, normal head pressure, and high evaporator superheat. This points to an issue with the low pressure control, which monitors the suction pressure and cuts off the compressor if it drops too low. If the low pressure control contacts are stuck open, the compressor will not run even though the suction pressure is above the normal cut-in point, resulting in the observed symptoms of warm air temperature and compressor not operating. The other options are incorrect because they would not explain the high suction pressure and normal head pressure - excessive cooling water flow (A) would lower the head pressure, and a stuck open or closed liquid line solenoid valve (B, C) would affect the liquid refrigerant flow and result in different pressure/superheat characteristics.