Question 171Refrigeration & AC - 1st Asst/Chief

The correct answer is C) The lube oil differential pressure switch. The lube oil differential pressure switch is a critical component in the control system of a ship's service refrigeration system. It monitors the differential pressure between the compressor's lube oil supply and the refrigerant suction pressure. If this differential pressure drops below a set threshold, the switch will shut down the compressor to prevent damage from inadequate lubrication. In the described scenario, where the compressor starts but then stops shortly after, the lube oil differential pressure switch is the most likely culprit. This switch has likely detected a drop in the lube oil differential pressure, triggering the compressor to shut down as a protective measure. The other answer choices, while potentially relevant in other refrigeration system issues, are not the correct explanation for the described problem.