EPA Section 608 Universal Certification ExamType III (Low-Pressure Appliances)Medium
A technician is performing a recovery from a low-pressure chiller. To ensure maximum efficiency and prevent liquid refrigerant from entering the recovery compressor, what component should be used in the recovery setup?
- AA filter-drier in the liquid line.
- BA liquid receiver on the recovery unit.
- CA sight glass in the vapor line.
- DA crankcase heater on the recovery compressor.
Show answer & explanationAnswer & explanation
Correct answer: D. A crankcase heater on the recovery compressor.
A crankcase heater on the recovery compressor helps to boil off any liquid refrigerant that might migrate to the compressor's crankcase, preventing liquid slugging and protecting the compressor from damage.
Why the other options are wrong
- A. A filter-drier cleans the refrigerant but doesn't prevent liquid from entering the compressor.
- B. A liquid receiver stores liquid refrigerant but is typically part of the system being recovered from, not the recovery unit for preventing compressor slugging.
- C. A sight glass indicates refrigerant state but doesn't prevent liquid from entering the compressor.
Recovery Compressor Protection
During refrigerant recovery, it is essential to protect the recovery compressor from liquid refrigerant, which can cause severe mechanical damage.
- Liquid slugging damages compressors.
- Crankcase heaters prevent liquid migration.
- Vapor recovery is generally safer for compressors.
Memory trick: Heat the crankcase, save the case!