EPA Section 608 Universal Certification ExamType III (Low-Pressure Appliances)Easy
Which component of a low-pressure chiller system is designed to remove non-condensable gases from the system?
- APurge unit
- BEvaporator
- CExpansion valve
- DCondenser
Show answer & explanationAnswer & explanation
Correct answer: A. Purge unit
Low-pressure chillers often operate below atmospheric pressure, which can lead to air (non-condensables) leaking into the system. A purge unit is specifically designed to remove these non-condensable gases from the condenser.
Why the other options are wrong
- B. The evaporator absorbs heat, causing refrigerant to boil, but is not involved in non-condensable removal.
- C. The expansion valve controls refrigerant flow to the evaporator, not non-condensable removal.
- D. The condenser cools and condenses refrigerant vapor, but does not actively remove non-condensables.
Purge Unit Function
A device used in low-pressure refrigeration systems to remove non-condensable gases (primarily air) that may leak into the system due to operation below atmospheric pressure.
- Used in low-pressure systems.
- Removes non-condensable gases (air).
- Typically connected to the condenser.
- Improves system efficiency and prevents corrosion.
Memory trick: Low pressure, air in, purge unit kicks, gases out, win!