Refrigerant PT Chart Calculator
Free refrigerant PT chart lookup. Convert pressure to saturation temperature (or temperature to pressure) for R-410A, R-454B, R-32, R-22, R-134a, R-404A, R-407C, R-448A, and R-449A, with bubble/dew for glide blends.
How to read a pressure-temperature chart
A PT chart maps a refrigerant’s saturation pressure to its saturation temperature — the point where it’s boiling/condensing. That conversion is the foundation of charging and diagnostics: you read a gauge pressure, convert it to a saturation temperature, and compare it to a measured line temperature to get superheat or subcooling.
- Superheat = suction line temperature − saturation temperature at suction pressure (use the dew point on a blend).
- Subcooling = saturation temperature at liquid pressure − liquid line temperature (use the bubble point on a blend).
Why the refrigerant matters
Each refrigerant has a completely different pressure curve. At 40°F, for example:
| Refrigerant | ~Saturation pressure at 40°F |
|---|---|
| R-22 | 69 PSIG |
| R-134a | 35 PSIG |
| R-404A | 84 PSIG |
| R-410A | 118 PSIG |
| R-32 | 121 PSIG |
| R-454B | ~80 PSIG (bubble) |
Reading the wrong refrigerant’s chart will throw off superheat and subcooling and can cause a serious mischarge.
Glide blends: bubble vs. dew
Zeotropic blends boil and condense across a temperature range called glide. They have two saturation points at any pressure:
- Bubble point (saturated liquid) — use for subcooling on the liquid line.
- Dew point (saturated vapor) — use for superheat on the suction line.
This tool reports both for the glide blends (R-407C, R-448A, R-449A, and the small-glide R-454B). Single-component and near-azeotropic refrigerants (R-22, R-32, R-134a, R-404A, R-410A) have effectively no glide — bubble and dew are the same.
Pair this chart with the Superheat and Subcooling calculators to finish the diagnosis.
How FieldPad helps in the field
Look up the saturation temperature here, then keep the readings with the equipment. FieldPad logs your pressures, line temperatures, superheat, and subcooling against the system and the client, attaches them to the job, and rolls the work into a signed invoice — offline, on your iPhone, with the full charging history on one record.
Stop Re-Running These Numbers by Hand
FieldPad is the all-in-one iPhone CRM for solo HVAC techs — clients, scheduling, estimates, invoices with signatures, inventory, and equipment history. Keep your readings on the job, the client, and the equipment, all in one offline-ready app. EPA Section 608 and Subpart C compliance included.
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