What defines a 'low-pressure appliance' (Type III)?
Not quite. The answer is B: Equipment using a refrigerant whose liquid saturation pressure is below 45 psia at 104 °F (such as R-123 in many centrifugal chillers), so the low side normally runs below atmospheric pressure
Low-pressure appliances are defined by how the refrigerant behaves at the system's operating conditions — centrifugal chillers using low-pressure refrigerants like R-123 run with their low side under vacuum during normal operation, which is the opposite condition from every high-pressure (Type II) refrigerant and drives fundamentally different service, leak-detection, and evacuation procedures.
Reference: 40 CFR Part 82 § 82.152 (Definition of 'low-pressure appliance')
Checked against the official text
Read the eCFR text current through 2026-10-30 of § 82.152. Definition: appliance using a refrigerant with a liquid-phase saturation pressure below 45 psia at 104 °F (examples R-11, R-123, R-113, R-245fa).
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