Question 178Refrigeration & AC - 1st Asst/Chief

The correct answer is C) short cycle on low pressure cutout. When the evaporator coil is accumulating excessive frost due to a failure of the defrost mechanism, the cooling capacity of the refrigerator will be reduced. This will cause the refrigerant pressure on the low side of the system to drop, triggering the low pressure cutout switch. As a result, the compressor will short cycle, turning on and off repeatedly, instead of running continuously. The other options are incorrect because: A) the compressor would not run continuously due to the low pressure cutout; B) the compressor would not fail to start, it would simply short cycle; and D) the high pressure cutout would not be the issue in this scenario, as the problem is related to the low side of the system.