R-ProField casesRefrigeration systems

Non-Condensable Gas (Air) in Circuit

Likely causes

Refrigerant charged without sufficient vacuum

Check: Stop unit and compare measured vs saturation pressure (excess = non-condensable gas)

What to do: Stop unit and compare measured vs saturation pressure (excess = non-condensable gas) → Recover all refrigerant → Evacuate 30+ minutes to ≤500 μm Hg → Purge charging hoses, then recharge by weight → Confirm high-side pressure normalizes

Air ingress during leak repair

Check: Recover all refrigerant

What to do: Recover all refrigerant → Evacuate 30+ minutes to ≤500 μm Hg → Purge charging hoses, then recharge by weight → Confirm high-side pressure normalizes

Air in charging hoses not purged

Check: Evacuate 30+ minutes to ≤500 μm Hg

What to do: Evacuate 30+ minutes to ≤500 μm Hg → Purge charging hoses, then recharge by weight → Confirm high-side pressure normalizes

Field tip

Non-condensable gas contaminating the circuit is causing abnormally high pressure. Fully recover refrigerant, re-evacuate, and recharge. Send contaminated refrigerant to a reclamation facility.

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