Type III — low-pressure appliancesDifficulty 2/5
A low-pressure centrifugal chiller has begun purging far more frequently than before. What does this most likely indicate?
- AAir and moisture are being drawn into the system through a leak below atmospheric
- BRefrigerant is escaping from the system through a leak above atmospheric pressure
- CThe chiller is overcharged and the purge unit is removing the excess refrigerant
- DThe purge unit has failed and is cycling without removing any gas from the system
Show answer and rationale
Correct: A. A low-pressure machine runs below atmospheric pressure, so a leak lets air in rather than letting refrigerant out. The purge unit then works harder removing the non-condensables, which is the signature symptom.
- B — The system sits below atmospheric pressure, so the pressure gradient drives air inward.
- C — Purge units remove non-condensable gases, not surplus refrigerant from an overcharge.
- D — A failed purge unit would show as rising non-condensables, not as increased purging.