EPA Section 608 Universal Certification ExamType III (Low-Pressure Appliances)Medium
A technician is performing a recovery from a low-pressure chiller. After the bulk liquid has been removed, what must be done to ensure all remaining refrigerant vapor is recovered?
- AThe system must be pressurized with nitrogen to force out remaining vapor.
- BThe chiller's purge unit must be activated to remove residual vapor.
- CThe system's water boxes must be drained to prevent freezing.
- DThe recovery unit must be run until a deep vacuum is achieved.
Show answer & explanationAnswer & explanation
Correct answer: D. The recovery unit must be run until a deep vacuum is achieved.
After removing the bulk liquid, the remaining refrigerant vapor in a low-pressure system must be recovered to the required vacuum level. This is achieved by running the recovery unit to pull a deep vacuum.
Why the other options are wrong
- A. Pressurizing with nitrogen is dangerous and contaminates the refrigerant.
- B. The purge unit removes non-condensables, not bulk refrigerant vapor during recovery.
- C. Draining water boxes prevents freezing but doesn't remove refrigerant vapor.
Low-Pressure Vapor Recovery
The process of removing remaining refrigerant vapor from a low-pressure system after the bulk liquid has been recovered.
- Achieved by pulling a deep vacuum.
- Ensures compliance with recovery standards.
- Prevents refrigerant release.
Memory trick: Liquid out, then vacuum the vapor down low.