Question 100Refrigeration & AC - Assistant Engineer

70% to pass

The compressor used in a water-cooled air conditioning system is short cycling. A service check determines that the suction pressure remains above the normal cut-in point during cycling and that the discharge pressure rapidly builds up to the cut-out point while running and gradually falls to the cut-in point during the off cycle. What is likely the cause?

Aback seated discharge service valve
Breduction in condenser water flow (scaled condenser)
Cloosely fitted compressor drive belt
Dfront seated liquid line service valve
AI Explanation

The correct answer is B) reduction in condenser water flow (scaled condenser). The explanation is as follows: 1. Confirmation of the correct answer: B) reduction in condenser water flow (scaled condenser) is the correct answer. 2. Explanation of the reasoning: In a water-cooled air conditioning system, the compressor relies on the condenser to dissipate the heat from the refrigerant. If the condenser water flow is reduced, for example, due to a scaled condenser, the condenser's ability to effectively remove heat is diminished. This causes the discharge pressure to rapidly build up to the cut-out point while the compressor is running, and the suction pressure remains above the normal cut-in point, leading to short cycling of the compressor. 3. Explanation of why the other options are incorrect: A) back seated discharge service valve, C) loosely fitted compressor drive belt, and D) front seated liquid line service valve would not cause the specific symptoms described in the question, where the suction pressure remains above the normal cut-in point and the discharge pressure rapidly builds up to the cut-out point.

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