EPA EPA System Recovery and Evacuation Procedures 1 — Questions and Answers
Question 1: What is the required recovery level (in inches of mercury vacuum) for systems with less than 200 pounds of refrigerant manufactured before November 15, 1993, when using recovery-only equipment made before that date?
- 0 psig
- 4 inches Hg vacuum (Correct answer)
- 0 inches Hg (0 psig)
- 10 inches Hg vacuum
Correct answer: 4 inches Hg vacuum
For pre-1993 systems under 200 lbs using pre-1993 recovery equipment, the required evacuation level is 4 inches of mercury vacuum.
Question 2: Before opening a refrigeration system for major repairs, what must a technician do first?
- Add dye to locate leaks
- Recover the refrigerant from the system (Correct answer)
- Pressurize the system with nitrogen
- Replace the filter drier
Correct answer: Recover the refrigerant from the system
Federal regulations under Section 608 require technicians to recover refrigerant before opening any system to prevent venting to the atmosphere.
Question 3: What is the evacuation requirement for small appliances (systems containing 5 lbs or less of refrigerant) during recovery?
- 90% recovery of refrigerant
- 80% recovery if the compressor is not operating (Correct answer)
- 80% or 4-inch vacuum depending on equipment manufacture date
- No evacuation required for small appliances
Correct answer: 80% recovery if the compressor is not operating
For small appliances with inoperative compressors, EPA requires recovery of 80% of refrigerant; if the compressor operates, 90% recovery is required.
Question 4: What is the primary purpose of deep evacuation before charging a refrigeration system?
- To increase system efficiency by boosting pressure
- To remove moisture and non-condensable gases from the system (Correct answer)
- To test the compressor's pumping capacity
- To verify the refrigerant charge weight
Correct answer: To remove moisture and non-condensable gases from the system
Deep evacuation removes moisture and non-condensable gases (such as air and nitrogen) that can cause acid formation, elevated pressures, and system damage.
Question 5: Which instrument is used to measure the vacuum level during system evacuation?
- Manifold gauge set only
- Electronic micron gauge (vacuum gauge) (Correct answer)
- Clamp-on ammeter
- Sling psychrometer
Correct answer: Electronic micron gauge (vacuum gauge)
An electronic micron gauge accurately measures deep vacuum levels in microns of mercury (μm Hg), which manifold gauges cannot read precisely enough.
Question 6: What does a 'standing vacuum test' verify after system evacuation?
- That the system holds the required vacuum without rising, confirming no leaks or moisture (Correct answer)
- That the compressor can maintain vacuum during operation
- That the refrigerant charge is correct
- That non-condensables have been fully removed
Correct answer: That the system holds the required vacuum without rising, confirming no leaks or moisture
A standing vacuum test confirms system integrity by isolating the vacuum pump and monitoring whether the system vacuum holds steady or rises, indicating leaks or residual moisture.
EPA EPA System Recovery and Evacuation Procedures 1
What is the required recovery level (in inches of mercury vacuum) for systems with less than 200 pounds of refrigerant manufactured before November 15, 1993, when using recovery-only equipment made before that date?