EPA Section 608 Universal Certification ExamType I (Small Appliances)Easy
A technician is performing a leak repair on a small appliance containing R-134a. After successfully repairing the leak, what is the next mandatory step before recharging the system?
- AAdd a small amount of R-134a to check for proper operation.
- BPressurize the system with nitrogen to 150 psi.
- CPerform a final leak check using soap bubbles.
- DEvacuate the system to a deep vacuum.
Show answer & explanationAnswer & explanation
Correct answer: D. Evacuate the system to a deep vacuum.
After any repair on a refrigeration system, it is mandatory to evacuate the system to a deep vacuum. This removes non-condensables (like air) and moisture, which can cause system inefficiencies, corrosion, and component damage.
Why the other options are wrong
- A. Adding refrigerant to check operation before evacuation would introduce it into a potentially contaminated system.
- B. Pressurizing with nitrogen is typically done for leak testing, not as the final step before charging.
- C. A final leak check is typically done after pressurizing with nitrogen, or after charging, but not as the immediate next step after repair before vacuum.
Post-Repair Evacuation
After any repair on a refrigeration system, it is mandatory to evacuate the system to a deep vacuum to remove all non-condensables and moisture before recharging.
- Removes air and other non-condensable gases.
- Eliminates moisture, preventing acid formation and corrosion.
- Ensures optimal system performance and longevity.
- Required before introducing new refrigerant.
Memory trick: Repair is done, now the vacuum's begun!