Why must oxygen never be used to pressurize a refrigeration system for leak testing?
Safety · EPA 608 Type II. The correct answer, and the reasoning behind it.
Hermetic compressors under vacuum and other high-pressure hazards.
The question
Why must oxygen never be used to pressurize a refrigeration system for leak testing?
- It reacts with the refrigerant to form hydrochloric acid
- It can explode in contact with compressor oilCorrect answer
- It leaks out too fast to measure
- It is not detectable by any test
Why “It can explode in contact with compressor oil” is correct
Oxygen under pressure can ignite or explode when it meets oil, and every system contains compressor oil. Dry nitrogen is the safe choice for pressure testing.
Source: EPA: Test Topics
Why the other answers are wrong
- It reacts with the refrigerant to form hydrochloric acid — The danger is combustion with oil, not acid.
- It leaks out too fast to measure — Leak rate is not the reason oxygen is forbidden.
- It is not detectable by any test — Detectability is not the problem; the explosion risk is.
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