Refrigerant Contamination UK: How to Identify and Handle Mixed or Contaminated Gas

Why Refrigerant Contamination Is a Serious Problem

Refrigerant contamination occurs when a system contains the wrong gas, a mixture of different refrigerants, or gas that has been degraded by moisture, oil or non-condensables. Contaminated refrigerant can damage compressors, reduce system efficiency and create safety hazards — and identifying it quickly saves expensive repair costs.

Common Causes of Refrigerant Contamination in the UK

• Wrong refrigerant added: Topping up with an incorrect gas (e.g. adding R32 to an R410A system by mistake)
• Recovered gas reused improperly: Recycled gas from a different system used in a new one
• Moisture ingress: Inadequate vacuum before charging, or system opened to atmosphere
• Air ingress: Non-condensable gases from poor vacuum or leaky connections
• Oil contamination: Wrong oil type introduced, or excessive oil carryover from recovery equipment

How to Identify Contaminated Refrigerant

Refrigerant Identifier

A refrigerant identifier (analyser) is the fastest and most reliable way to check gas composition. Modern analysers can identify mixed or incorrect refrigerants in minutes and are essential for any engineer working on systems with an unknown service history.

Abnormal System Pressures

If measured system pressures do not match the expected PT data for the specified refrigerant, contamination or incorrect gas is a likely cause. Compare against PT charts for R32, R410A or R407C as appropriate.

Non-Condensables

Air or nitrogen in the system shows as elevated head pressure with normal subcooling. The system may cycle on high pressure cutout. A non-condensable purge is required — or full recover, vacuum and recharge.

What to Do With Contaminated Refrigerant

Recover contaminated gas into a dedicated recovery cylinder and label it clearly. Send it to an approved reclaim facility — do not mix it back into supply cylinders. After recovery, fully evacuate the system and recharge with verified correct refrigerant.

For clean refrigerant supply across all common gases, browse our full UK refrigerant range.