Why is heating the refrigerant preferred over nitrogen for pressurizing an R-123 chiller for a leak test?

Leak detection · EPA 608 Type III. The correct answer, and the reasoning behind it.

Pressurizing low-pressure systems for leak tests, signs of leaks, inspections and reports.

The question

Why is heating the refrigerant preferred over nitrogen for pressurizing an R-123 chiller for a leak test?

• ANitrogen reacts with R-123 to form acids
• BNitrogen must be purged out later, and refrigerant goes with itCorrect answer
• CNitrogen cannot raise the pressure of a chiller above atmospheric
• DHot water finds leaks by changing the water color

Why “Nitrogen must be purged out later, and refrigerant goes with it” is correct

Any nitrogen added to a low-pressure chiller stays as a noncondensable gas and has to be purged out afterward, and some refrigerant goes with it. Heating the refrigerant raises pressure without adding anything that must be removed, which is why EPA ranks hot water and devices like Prevac ahead of nitrogen.

Source: EPA: Test Topics; 40 CFR 82.156(a)(1)(ii)

Why the other answers are wrong

• Nitrogen reacts with R-123 to form acids — Nitrogen is inert and does not react with R-123.
• Nitrogen cannot raise the pressure of a chiller above atmospheric — Nitrogen can easily raise pressure; the problem is getting it back out.
• Hot water finds leaks by changing the water color — Hot water only raises pressure; it does not mark leaks.

Practice more of this

More EPA 608 Type III practice questions, or see every EPA 608 practice test.