USCG Exam PracticeRefrigeration cycle and components
A refrigeration engineer finds that the high-side pressure is elevated, the discharge temperature is high, and the compressor is working harder than normal, but the sight glass shows a solid liquid column and the suction pressure is normal. Which of the following faults is LEAST consistent with these readings?
- A. Fouled or scaled condenser tubes
- B. Reduced seawater flow to the condenser
- C. Non-condensable gas trapped in the condenser shell
- ✓ Refrigerant undercharge with a system leakCorrect
Why D is correct
Refrigerant undercharge produces low suction pressure, low head pressure, and bubbles in the sight glass — the opposite of what is observed here. Fouled tubes, reduced cooling water, and non-condensable gas all impair condenser heat rejection and raise head pressure while leaving suction pressure and the sight glass relatively normal, which is consistent with the readings described.