Under 40 CFR 82.152, what makes an appliance a "low-pressure appliance"?

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

Under 40 CFR 82.152, what makes an appliance a "low-pressure appliance"?

• AIts refrigerant has a saturation pressure below 45 psig at 77 °F
• BIts refrigerant's saturation pressure is below 45 psia at 104 °FCorrect answer
• CIts refrigerant has a saturation pressure below 170 psia at 104 °F
• DIts evaporator runs below atmospheric pressure when operating

Why “Its refrigerant's saturation pressure is below 45 psia at 104 °F” is correct

EPA sorts appliances by the saturation pressure of their refrigerant at 104 °F. A refrigerant whose liquid-phase saturation pressure is below 45 psia at that temperature makes the appliance low-pressure, which is why R-11 and R-123 centrifugal chillers fall in this class and follow the 25 mm Hg absolute evacuation level.

Source: 40 CFR 82.152

Why the other answers are wrong

• Its refrigerant has a saturation pressure below 45 psig at 77 °F — The definition uses psia, not psig, and is set at 104 °F, not room temperature.
• Its refrigerant has a saturation pressure below 170 psia at 104 °F — 170 psia at 104 °F is the top of the medium-pressure range, not the low-pressure limit.
• Its evaporator runs below atmospheric pressure when operating — Many low-pressure chillers do run in a vacuum, but the legal definition is based on saturation pressure at 104 °F.

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