USCG Exam PracticeRefrigeration principles and systems
A freezer room evaporator coil has accumulated a heavy layer of frost. What is the direct operational consequence if defrosting is not performed?
- A. Suction pressure will rise above normal operating range
- ✓ The frost layer will insulate the coil and block airflow, steadily reducing cooling capacityCorrect
- C. Liquid refrigerant will flood back to the compressor suction
- D. The condenser will lose the ability to reject heat, raising discharge pressure
Why B is correct
NAVEDTRA 14075 §6-5 states that frost buildup insulates the coil and blocks airflow, steadily cutting capacity. Frost accumulation is an evaporator-side problem and does not directly cause liquid floodback or affect condenser performance.
Cited:NAVEDTRA 14075 §6-5