USCG Exam PracticeRefrigeration and air conditioning
What is the primary hazard of liquid floodback reaching a reciprocating refrigeration compressor?
- A. It causes the suction pressure to rise above the high-pressure cutout setpoint
- B. It dilutes the crankcase oil, reducing lubrication to the shaft seal
- ✓ Liquid cannot be compressed and can break valves, connecting rods, or the crankcaseCorrect
- D. It freezes at the suction reed valves and prevents the compressor from drawing vapor
Why C is correct
NAVEDTRA 14075 §6-2 states that if liquid refrigerant returns to the suction (slugging or liquid floodback), it cannot be compressed and can break valves, rods, or the crankcase, constituting a serious casualty. The system is arranged to ensure refrigerant is fully evaporated and slightly superheated before reaching the compressor.
Cited:NAVEDTRA 14075 §6-2