Using recovery equipment made in 2021, what levels apply before major repairs on a 300-pound R-123 chiller…

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

Using recovery equipment made in 2021, what levels apply before major repairs on a 300-pound R-123 chiller and a 300-pound R-134a chiller?

• A25 mm Hg absolute for the R-123; 15 inches of Hg vacuum for the R-134aCorrect answer
• B25 mm Hg absolute for both chillers
• C15 inches of Hg vacuum for both chillers
• D10 inches of Hg vacuum for the R-123; 25 mm Hg absolute for the R-134a

Why “25 mm Hg absolute for the R-123; 15 inches of Hg vacuum for the R-134a” is correct

R-123 is a low-pressure refrigerant, so its chiller must reach 25 mm Hg absolute. R-134a has a saturation pressure between 45 and 170 psia at 104 °F, making it medium-pressure; with 200 pounds or more and post-1993 equipment, Table 1 calls for 15 inches of Hg vacuum.

Source: 40 CFR 82.156(a), Table 1; 40 CFR 82.152

Why the other answers are wrong

• 25 mm Hg absolute for both chillers — R-134a is a medium-pressure refrigerant, so its chiller follows the medium-pressure row, not the low-pressure one.
• 15 inches of Hg vacuum for both chillers — R-123 is low-pressure and must go to 25 mm Hg absolute.
• 10 inches of Hg vacuum for the R-123; 25 mm Hg absolute for the R-134a — This reverses the classes; the deep 25 mm Hg level belongs to the low-pressure R-123 chiller.

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