EPA Section 608 Universal Certification ExamType I (Small Appliances)Medium
A technician is preparing to recover refrigerant from a small appliance. To prevent the intake of air and non-condensables into the recovery equipment and cylinder, what critical step should be performed immediately before connecting to the appliance?
- APurge the recovery machine with nitrogen.
- BPressurize the recovery cylinder with recovered refrigerant.
- CHeat the recovery cylinder to create a pressure differential.
- DEvacuate the recovery hoses and manifold.
Show answer & explanationAnswer & explanation
Correct answer: D. Evacuate the recovery hoses and manifold.
Evacuating the recovery hoses and manifold removes any air or non-condensables present in these components before they are connected to the appliance. This ensures that only refrigerant is transferred to the recovery cylinder, preventing contamination.
Why the other options are wrong
- A. Purging with nitrogen is typically done for system leak checking or flushing, not for preventing air in recovery hoses.
- B. Pressurizing the recovery cylinder with refrigerant is not the primary method to prevent air in hoses; it would already assume refrigerant is present.
- C. Heating the recovery cylinder would increase its pressure, which might hinder recovery, and does not address air in the hoses.
Pre-Recovery Evacuation of Hoses
Before connecting to a refrigerant system for recovery, it is crucial to evacuate the recovery hoses and manifold to remove air and moisture, preventing contamination of recovered refrigerant.
- Prevents non-condensables (air) from entering the recovery cylinder.
- Ensures purity of recovered refrigerant.
- Performed with a vacuum pump attached to the manifold.
Memory trick: Before you connect, remove the air, or the refrigerant's purity you'll impair!