CFC Commercial Refrigeration Systems 2 — Questions and Answers
Question 1: In a commercial walk-in cooler, which component is responsible for removing heat from the refrigerated space?
- Condenser coil
- Evaporator coil (Correct answer)
- Compressor crankcase
- Receiver tank
Correct answer: Evaporator coil
The evaporator coil absorbs heat from the refrigerated space, causing refrigerant to evaporate and cool the air inside.
Question 2: What is the purpose of a liquid-line filter drier in a commercial refrigeration system?
- Increase refrigerant pressure
- Remove moisture and contaminants from refrigerant (Correct answer)
- Separate liquid from vapor refrigerant
- Regulate refrigerant flow rate
Correct answer: Remove moisture and contaminants from refrigerant
A liquid-line filter drier removes moisture, acid, and solid contaminants that could damage system components or cause ice blockages.
Question 3: A commercial refrigeration system shows high discharge pressure but normal suction pressure. The most likely cause is:
- Low refrigerant charge
- Restricted metering device
- Dirty or fouled condenser (Correct answer)
- Worn compressor valves
Correct answer: Dirty or fouled condenser
A dirty or fouled condenser restricts heat rejection, causing discharge pressure to rise while suction pressure remains normal.
Question 4: Which EPA Section 608 refrigerant handling practice is required when opening a commercial refrigeration system for repair?
- Purge refrigerant to atmosphere before opening
- Recover refrigerant to required levels before opening (Correct answer)
- Add nitrogen before opening
- Equalize pressure to 0 psig before opening
Correct answer: Recover refrigerant to required levels before opening
EPA Section 608 requires technicians to recover refrigerants to specified levels before opening any system containing CFCs, HCFCs, or HFCs.
Question 5: What does superheat at the evaporator outlet indicate in a properly operating commercial refrigeration system?
- All refrigerant has been converted back to liquid
- Refrigerant vapor is warmer than its saturation temperature (Correct answer)
- The system is overcharged with refrigerant
- Compressor is running at reduced capacity
Correct answer: Refrigerant vapor is warmer than its saturation temperature
Superheat at the evaporator outlet means the refrigerant vapor temperature exceeds its saturation temperature, ensuring only dry vapor enters the compressor.
Question 6: A commercial refrigeration rack system uses multiple compressors in parallel primarily to:
- Reduce refrigerant charge requirements
- Allow capacity modulation and redundancy (Correct answer)
- Eliminate the need for a receiver
- Increase system operating pressure
Correct answer: Allow capacity modulation and redundancy
Multiple parallel compressors allow the rack to stage capacity up or down based on load demand and provide redundancy if one compressor fails.
Question 7: When leak checking a commercial refrigeration system after repair, which method is preferred to avoid introducing moisture?
- Air pressure test
- Dry nitrogen pressure test with electronic leak detector (Correct answer)
- Carbon dioxide pressure test
- Water submersion test
Correct answer: Dry nitrogen pressure test with electronic leak detector
Dry nitrogen is inert, moisture-free, and safe for leak testing; an electronic detector then locates the exact leak site without contaminating the system.
CFC Commercial Refrigeration Systems 2
In a commercial walk-in cooler, which component is responsible for removing heat from the refrigerated space?