EPA Section 608 Universal Certification ExamType II (High-Pressure Appliances)Medium
A technician is performing a recovery from a high-pressure appliance containing R-404A. The technician observes that the recovery cylinder is significantly warmer than the ambient temperature and the pressure inside the cylinder is rising rapidly, indicating the presence of non-condensables. What is the MOST likely consequence of having non-condensables in the recovery cylinder?
- AImproved refrigerant purity.
- BFaster recovery rates.
- CLower-than-expected cylinder pressure.
- DIncreased pressure in the recovery cylinder, impeding recovery.
Show answer & explanationAnswer & explanation
Correct answer: D. Increased pressure in the recovery cylinder, impeding recovery.
Non-condensables (like air or nitrogen) in the recovery cylinder increase the total pressure within the cylinder beyond what the refrigerant alone would exert. This higher pressure reduces the pressure differential between the system and the cylinder, making it harder for the recovery unit to transfer refrigerant, thus slowing down or impeding the recovery process.
Why the other options are wrong
- A. Non-condensables are contaminants and decrease, not improve, refrigerant purity.
- B. Non-condensables increase pressure, which impedes, not speeds up, recovery.
- C. Non-condensables add to the total pressure, resulting in higher-than-expected cylinder pressure.
Impact of Non-Condensables on Recovery
Non-condensable gases (like air or nitrogen) in a refrigeration system or recovery cylinder negatively impact recovery efficiency and system performance.
- Non-condensables increase system and recovery cylinder pressure.
- This reduces the pressure differential, slowing down recovery.
- They can lead to higher discharge pressures and temperatures in the recovery unit.
- They reduce the system's cooling capacity and efficiency if left in the system.
Memory trick: Non-condensables: More PRESSURE, LESS performance.