USCG Exam PracticeRefrigeration principles and systems
What condition causes the high-pressure cutout on a refrigeration compressor to trip?
- A. Loss of refrigerant charge reducing suction pressure below the set point
- B. Liquid refrigerant returning to the compressor suction
- ✓ Discharge pressure rising dangerously, such as from a fouled condenser or lost cooling waterCorrect
- D. Oil pressure in the crankcase falling below the minimum safe level
Why C is correct
NAVEDTRA 14075 §6-2 states the high-pressure cutout stops the compressor if discharge pressure rises dangerously, with causes including a dirty condenser, air in the system, or lost cooling water. Loss of charge trips the low-pressure cutout; liquid floodback is a mechanical casualty; low oil pressure trips the oil-pressure safety switch.
Cited:NAVEDTRA 14075 §6-2