Question 65Refrigeration/AC - 1st Asst/Chief70% 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?
AI Explanation
The correct answer is D) reduction in condenser water flow (scaled condenser).
The explanation is as follows:
1. The short-cycling of the compressor indicates an issue with the condenser's ability to reject heat, which is likely due to a reduction in condenser water flow caused by a scaled condenser.
2. In a water-cooled air conditioning system, the condenser relies on a steady flow of water to dissipate the heat from the refrigerant. If the condenser becomes scaled or fouled, the water flow is restricted, causing the discharge pressure to rapidly build up to the cut-out point while running and gradually fall to the cut-in point during the off cycle.
3. The other options, such as a front-seated liquid line service valve, a back-seated discharge service valve, or a loosely fitted compressor drive belt, are unlikely to cause the specific symptoms described in the question.
4. Therefore, the correct answer is D) reduction in condenser water flow (scaled condenser).
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