EPA Section 608 Universal Certification ExamType III (Low-Pressure Appliances)Medium
A technician is preparing to charge a low-pressure chiller with R-123. The most accurate way to charge the system is by:
- ACharging liquid refrigerant into the system's lowest pressure point, typically the evaporator charging valve.
- BCharging vapor refrigerant into the low-side service valve.
- CCharging liquid refrigerant into the high-side service valve.
- DCharging liquid refrigerant into the evaporator.
Show answer & explanationAnswer & explanation
Correct answer: A. Charging liquid refrigerant into the system's lowest pressure point, typically the evaporator charging valve.
For low-pressure chillers, the most accurate and safest method for charging is to introduce liquid refrigerant into the lowest pressure point of the system, which is typically the evaporator charging valve. This prevents over-pressurization and ensures proper refrigerant distribution.
Why the other options are wrong
- B. Charging vapor is very slow and less accurate for large charges.
- C. Charging liquid into the high side is generally for high-pressure systems, not low-pressure.
- D. While often the evaporator, the key is the 'lowest pressure point' for safety and accuracy.
Low-Pressure Chiller Charging Method
The recommended procedure for introducing refrigerant into a low-pressure chiller to ensure safety and accuracy.
- Liquid charging is preferred for speed and accuracy.
- Must be introduced into the lowest pressure point.
- Typically the evaporator charging valve.
Memory trick: Liquid low, evaporator flow.