EPA Section 608 Universal Certification ExamType II (High-Pressure Appliances)Medium
A technician is evacuating a high-pressure appliance containing R-407C after a major repair. The system capacity is 30 lbs. What is the MINIMUM required evacuation level for this system before recharging?
- A10 inches of Hg vacuum
- B25 inches of Hg vacuum
- C0 psig
- D500 microns of mercury
Show answer & explanationAnswer & explanation
Correct answer: D. 500 microns of mercury
For high-pressure appliances, specifically those with a system charge of less than 200 lbs, a major repair requires evacuation to 500 microns of mercury (0.5 mm Hg absolute). This ensures proper dehydration and removal of non-condensables.
Why the other options are wrong
- A. 10 inches of Hg vacuum is far too low and indicates little to no actual vacuum.
- B. 25 inches of Hg vacuum is an older, less stringent requirement and not deep enough for modern systems or major repairs.
- C. 0 psig (atmospheric pressure) is insufficient for proper evacuation and dehydration.
High-Pressure Appliance Evacuation Levels (Major Repair)
The minimum vacuum levels required by EPA regulations for high-pressure appliances after a major repair, before recharging.
- 500 microns is standard for most systems.
- Ensures dehydration and removal of non-condensables.
- Different levels apply for specific conditions (e.g., disposal).
Memory trick: To be truly clean, get down to the 'microns' in a major repair!