EPA Section 608 Universal Certification ExamType I (Small Appliances)Medium
A technician is performing a recovery on a small appliance containing R-134a. The recovery machine has an automatic non-condensable purge feature. When should this feature typically be activated during the recovery process?
- AOnly after the recovery is complete and the system is in a vacuum.
- BWhen the pressure in the recovery cylinder becomes excessively high.
- CAt the very beginning of the recovery, before any refrigerant is transferred.
- DContinuously throughout the entire recovery process.
Show answer & explanationAnswer & explanation
Correct answer: B. When the pressure in the recovery cylinder becomes excessively high.
The non-condensable purge feature on a recovery machine is designed to remove air and other non-condensable gases from the recovery cylinder. These gases cause the pressure in the cylinder to rise excessively, indicating their presence and the need for purging to maintain efficient recovery.
Why the other options are wrong
- A. Purging after recovery is complete is too late; the goal is to remove them during the process to maintain efficiency and avoid high pressure.
- C. Purging at the very beginning is not efficient; non-condensables accumulate as recovery progresses.
- D. Continuous purging can lead to refrigerant loss; it's typically activated when needed.
Non-Condensable Purge Activation
The non-condensable purge feature on a recovery machine should be activated when the pressure in the recovery cylinder becomes excessively high, indicating the presence of air or other non-condensable gases.
- Non-condensables increase recovery cylinder pressure.
- High pressure reduces recovery efficiency.
- Purging removes non-condensables, but can also lead to some refrigerant loss.
Memory trick: When the pressure's too high, let the non-condensables fly!