Which method may a technician use to bring an R-123 chiller up to 0 psig before a non-major repair?

Recovery requirements · EPA 608 Type III. The correct answer, and the reasoning behind it.

Evacuation levels for low-pressure appliances, and major versus non-major repairs.

The question

Which method may a technician use to bring an R-123 chiller up to 0 psig before a non-major repair?

• AControlled hot water or a built-in heating device such as PrevacCorrect answer
• BDry nitrogen from a regulated cylinder, with the nitrogen purged afterward
• CCompressed shop air fed through the purge connection
• DCarbon dioxide from a cylinder, purged afterward

Why “Controlled hot water or a built-in heating device such as Prevac” is correct

Low-pressure appliances whose refrigerant boils at or below 85 °F at standard atmospheric pressure, such as R-11 and R-123, must not be pressurized with methods that require later purging. Warming the refrigerant with controlled hot water or a built-in heating and pressurization device raises its own vapor pressure instead.

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

Why the other answers are wrong

• Dry nitrogen from a regulated cylinder, with the nitrogen purged afterward — R-123 boils below 85 °F at atmospheric pressure, so methods such as nitrogen that need later purging are not allowed.
• Compressed shop air fed through the purge connection — Air is a noncondensable that would have to be purged out and would contaminate the refrigerant.
• Carbon dioxide from a cylinder, purged afterward — CO2 would also need to be purged out later, which the rule forbids for R-123.

Practice more of this

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