CFC Recovery Equipment & Techniques 3 — Questions and Answers
Question 1: According to EPA Section 608, what is the required vacuum level before opening a system for non-major repairs on appliances with more than 200 pounds of refrigerant?
- 0 psig
- 4 inches Hg vacuum (Correct answer)
- 10 inches Hg vacuum
- 15 inches Hg vacuum
Correct answer: 4 inches Hg vacuum
EPA regulations require a 4-inch Hg vacuum for appliances containing more than 200 pounds of refrigerant before opening for non-major repairs.
Question 2: Which of the following refrigerants requires recovery equipment to be certified to a HIGHER standard due to its flammability?
- R-22
- R-410A
- R-290 (propane) (Correct answer)
- R-134a
Correct answer: R-290 (propane)
R-290 (propane) is an A3 flammable refrigerant requiring equipment specifically rated for flammable refrigerant handling.
Question 3: When recovering a blend refrigerant such as R-410A, which method is MOST effective for recovering both liquid and vapor phases efficiently?
- Vapor-only recovery from the low side
- Liquid recovery from the high side followed by vapor recovery from the low side (Correct answer)
- Vapor recovery from both high and low sides simultaneously
- Allow the refrigerant to boil off naturally into the recovery cylinder
Correct answer: Liquid recovery from the high side followed by vapor recovery from the low side
Recovering liquid first from the high side, then vapor from the low side maximizes efficiency and maintains blend composition.
Question 4: A recovery cylinder bearing a yellow top and gray body is designated for use with:
- Any recovered refrigerant (Correct answer)
- Flammable refrigerants only
- Mixed or unknown refrigerants
- Pure single-component refrigerants only
Correct answer: Any recovered refrigerant
The standard yellow-top gray-body color coding designates a cylinder approved for recovered refrigerants of any type.
Question 5: What is the purpose of the two-stage recovery process used with large commercial systems?
- To separate oil from refrigerant during recovery
- To recover liquid refrigerant first for speed, then capture remaining vapor (Correct answer)
- To allow the system compressor to pre-compress refrigerant before external recovery
- To comply with EPA requirements for split-phase recovery
Correct answer: To recover liquid refrigerant first for speed, then capture remaining vapor
The two-stage process recovers bulk liquid quickly, then uses the recovery machine to capture remaining low-pressure vapor.
Question 6: An oil-less recovery compressor is MOST advantageous when recovering refrigerant that:
- Is at low pressure and high temperature
- Will be recycled on-site and must not be contaminated with compressor oil (Correct answer)
- Contains high amounts of moisture
- Has a low global warming potential
Correct answer: Will be recycled on-site and must not be contaminated with compressor oil
Oil-less compressors prevent oil carryover into the recovered refrigerant, which is critical when the refrigerant will be recycled for reuse.
Question 7: If a recovery cylinder's pressure gauge shows a pressure higher than expected for the ambient temperature after recovery, the technician should suspect:
- A faulty pressure gauge
- The cylinder contains non-condensable gases such as air or nitrogen (Correct answer)
- The refrigerant has been over-recovered
- The cylinder is too cold
Correct answer: The cylinder contains non-condensable gases such as air or nitrogen
Non-condensable gases like air or nitrogen raise cylinder pressure above the saturation pressure expected at a given temperature.
CFC Recovery Equipment & Techniques 3
According to EPA Section 608, what is the required vacuum level before opening a system for non-major repairs on appliances with more than 200 pounds of refrigerant?