EPA Section 608 Universal Certification ExamType I (Small Appliances)Medium
A technician is recovering refrigerant from a small appliance. To prevent the intake of air and non-condensables into the recovery machine and cylinder, what is the correct procedure before opening the recovery cylinder valve?
- APressurize the recovery machine with refrigerant from the appliance.
- BRun the recovery machine for 5 minutes with the discharge valve closed.
- CPurge the recovery machine with nitrogen.
- DEvacuate the recovery machine and hoses to a deep vacuum.
Show answer & explanationAnswer & explanation
Correct answer: D. Evacuate the recovery machine and hoses to a deep vacuum.
Before beginning recovery, the recovery machine and its connecting hoses must be evacuated to a deep vacuum. This removes any air or moisture present in the equipment, preventing it from being introduced into the recovery cylinder or contaminating the recovered refrigerant.
Why the other options are wrong
- A. Pressurizing with refrigerant might introduce contaminants from the appliance or other parts of the system.
- B. Running the machine with the discharge valve closed serves no purpose for preventing air intake and could damage the machine.
- C. Nitrogen purge can remove air, but evacuation to a deep vacuum is more thorough for removing both air and moisture.
Pre-Recovery Evacuation
Before initiating refrigerant recovery, the recovery machine and all connecting hoses must be evacuated to a deep vacuum to remove air and moisture, preventing contamination of the recovered refrigerant and cylinder.
- Prevents non-condensables from entering the recovery cylinder.
- Ensures purity of recovered refrigerant for reclamation.
- Protects recovery equipment from moisture damage.
- Standard practice for all refrigerant recoveries.
Memory trick: Vacuum the lines, then recovery shines!