CFC Recovery Equipment & Techniques 5 — Questions and Answers
Question 1: What is the PRIMARY reason liquid refrigerant recovery is faster than vapor recovery?
- Liquid refrigerant is at lower pressure, making it easier to move
- Liquid refrigerant contains much more mass per unit volume than vapor (Correct answer)
- Liquid recovery does not require a compressor in the recovery machine
- Liquid refrigerant does not require an oil separator during recovery
Correct answer: Liquid refrigerant contains much more mass per unit volume than vapor
Liquid refrigerant is far denser than vapor, so the same volume of liquid contains significantly more refrigerant mass, speeding up the overall recovery process.
Question 2: A technician connects a recovery machine to a system and the machine runs but no refrigerant is being recovered. After checking connections, the NEXT step should be to:
- Increase the machine speed setting
- Check that the system service valves are open and the recovery cylinder valve is open (Correct answer)
- Replace the recovery machine's filter-drier
- Add nitrogen to the system to push refrigerant into the recovery cylinder
Correct answer: Check that the system service valves are open and the recovery cylinder valve is open
Closed service valves or a closed cylinder valve are the most common causes of zero flow despite the machine running.
Question 3: Which statement about recovering refrigerant from a system with a hermetic compressor burnout is CORRECT?
- The refrigerant can be recovered normally and sent to any reclaim facility
- The refrigerant should be labeled as contaminated and the reclaim facility must be notified of the burnout (Correct answer)
- The refrigerant must be vented immediately due to acid contamination
- Burnout contamination prevents recovery and the refrigerant must be neutralized on-site
Correct answer: The refrigerant should be labeled as contaminated and the reclaim facility must be notified of the burnout
Refrigerant from a burnout must be labeled as contaminated and the reclaim facility must be informed so they can handle it appropriately.
Question 4: EPA Section 608 defines 'substantially contribute' to ozone depletion. Under this standard, technicians are prohibited from knowingly venting refrigerants during:
- Purging of hoses only
- Maintenance, service, repair, and disposal of refrigerant-containing appliances (Correct answer)
- Initial system charging only
- Leak testing with refrigerant
Correct answer: Maintenance, service, repair, and disposal of refrigerant-containing appliances
Section 608 prohibits knowing venting during all phases of maintenance, service, repair, and disposal of equipment containing regulated refrigerants.
Question 5: When recovering refrigerant from a large chiller using a dedicated recovery unit, the technician should connect recovery hoses to:
- Only the low-side service port to prevent liquid slugging
- Only the high-side service port for maximum pressure differential
- Both high-side and low-side service ports for push-pull recovery (Correct answer)
- The oil drain port to recover refrigerant and oil simultaneously
Correct answer: Both high-side and low-side service ports for push-pull recovery
Large chillers benefit from push-pull recovery using both service ports to maximize recovery speed and efficiency.
Question 6: A recovery cylinder is rated with a maximum fill weight. The technician should NEVER fill a recovery cylinder beyond what percentage of its rated capacity by weight?
- 80% (Correct answer)
- 90%
- 95%
- 100%
Correct answer: 80%
Recovery cylinders must not be filled beyond 80% of their rated capacity by weight to allow for liquid expansion due to temperature changes.
Question 7: Which recovery technique is MOST appropriate when a system has both a liquid line service valve and a suction service valve accessible?
- Recover only from the liquid line to prevent compressor oil carryover
- Recover vapor from the suction side while simultaneously transferring liquid from the liquid line (Correct answer)
- Recover all refrigerant as vapor from the suction side for safest operation
- Use only the liquid line valve and bypass the suction side entirely
Correct answer: Recover vapor from the suction side while simultaneously transferring liquid from the liquid line
Recovering vapor from the suction side while simultaneously moving liquid from the liquid line uses both access points for maximum recovery speed.
CFC Recovery Equipment & Techniques 5
What is the PRIMARY reason liquid refrigerant recovery is faster than vapor recovery?