Refrigerants
The A2L refrigerant transition, R-410A and R-454B rules, what is legal to install and service, and what the change costs contractors and owners.
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Nitrogen Pressure Test: PSI by Manufacturer, Hold Times and Temperature Correction
How to nitrogen pressure test AC lines: test pressures and hold times from Goodman, Daikin, Mitsubishi and Rheem manuals, a worked temperature correction, brazing purge and the EPA…
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Refrigerant Oil: POE vs Mineral, PVE, What R-410A Uses and When You Can Mix
Refrigerant oil follows the refrigerant: mineral or alkylbenzene for R-22, POE or PVE for R-410A, POE for R-454B and R-32. Copeland, Danfoss, Rheem and oil maker data on…
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Schrader Valve on AC Systems: Cores, Caps, Port Sizes, Leaks and Locking Cap Code
A Schrader valve is the access valve in every AC service port. Here are the maker torque specs, 1/4 and 5/16 in. port threads, how leaking cores are…
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Filter Drier: What It Does, Liquid Line vs Bi-Flow, and When to Replace It
A filter drier traps moisture, acid and debris before they reach the metering device and compressor. Sporlan, Danfoss and Copeland data on types, clog signs, sizing and replacement,…
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R410a Pressure Chart: R-410A, R-454B and R-32 PT Table With How to Read It
A sourced PT table for R-410A, R-454B (dew and bubble) and R-32 from 0°F to 120°F, how to read it, why the high and low side ranges online…
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R32 Refrigerant: GWP 675, A2L Flammability, R-410A vs R-454B and Who Uses It
R-32 is difluoromethane: GWP 675 under 40 CFR 84, A2L mildly flammable, and legal under EPA’s 700 GWP cap. How it compares with R-410A and R-454B, and which…
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Refrigerant Recovery: EPA Vacuum Levels, Machines, Cylinders and the AIM Act Rules
Refrigerant recovery explained from the regulation text: the 40 CFR 82.156 vacuum levels table, certified machines, push-pull steps, 80% cylinder fill math and the AIM Act reclaim rules.
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Refrigerant Leak Detection: Methods Compared, A2L Sensors and the Federal Rules
Refrigerant leak detection methods compared from maker specs and EPA’s own definition, plus what A2L leak sensors do and which federal leak rules actually apply.
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Superheat and Subcooling Explained: Formulas, Worked R-410A and R-454B Examples
Superheat and subcooling measure how far refrigerant sits from its saturation point. Worked R-410A and R-454B examples from manufacturer PT charts, which method fits which metering device, and…
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Refrigerant Line Set: Sizes by Tonnage, Length Limits, Insulation and A2L Reuse
A refrigerant line set is the liquid and suction tubing between the outdoor unit and indoor coil. Here are manufacturer sizes by tonnage, length and lift limits, insulation…