R404A pressure temperature chart (PT)
An R404A pressure temperature chart (PT chart) is a saturation lookup for R404A in the two-phase region. Because R404A is a refrigerant blend, saturation can be represented by two endpoints: bubble and dew. Different charts and apps may choose different conventions.
Bubble vs dew (blend convention)
For blends, phase change can happen over a temperature range (temperature glide). A common convention is:
- Bubble point (often mapped with Q=0): liquid-side saturation endpoint.
- Dew point (often mapped with Q=1): vapor-side saturation endpoint.
Pressure basis: absolute vs gauge
The tables below use absolute pressure (kPa(a), bar(a), psi(a)). Many field gauges display gauge pressure (relative to ambient). Converting requires local atmospheric pressure:
Learn more: Gauge vs absolute pressure (psig vs psia).
R404A saturation pressure vs temperature (reference tables)
Generated using CoolProp (the same property engine used by FluidTool). For blends, we provide both endpoints: bubble (Q=0) and dew (Q=1). This page is educational and does not provide diagnostic target pressures.
| T (°C) | T (°F) | Psat bubble (kPa(a)) | Psat dew (kPa(a)) | Bubble (bar(a)) | Dew (bar(a)) | Bubble (psi(a)) | Dew (psi(a)) |
|---|---|---|---|---|---|---|---|
| -20 | -4 | 307.1 | 300.2 | 3.071 | 3.002 | 44.5 | 43.5 |
| -10 | 14 | 439.1 | 430.7 | 4.391 | 4.307 | 63.7 | 62.5 |
| 0 | 32 | 610.2 | 600.3 | 6.102 | 6.003 | 88.5 | 87.1 |
| 10 | 50 | 827.1 | 815.7 | 8.271 | 8.157 | 120.0 | 118.3 |
| 20 | 68 | 1097.1 | 1084.4 | 10.971 | 10.844 | 159.1 | 157.3 |
| 30 | 86 | 1428.4 | 1414.5 | 14.284 | 14.145 | 207.2 | 205.2 |
| 40 | 104 | 1829.5 | 1814.9 | 18.295 | 18.149 | 265.4 | 263.2 |
| 50 | 122 | 2310.9 | 2296.1 | 23.109 | 22.961 | 335.2 | 333.0 |
| 60 | 140 | 2885.0 | 2871.2 | 28.850 | 28.712 | 418.4 | 416.4 |
| 70 | 158 | 3572.1 | 3563.3 | 35.721 | 35.633 | 518.1 | 516.8 |
How to verify in FluidTool
- Open FluidTool with R404A selected: /?fluid=R404A
- Choose a Two-phase input pair (Temperature & Quality / T + Q).
- Set Q=0 to reproduce the bubble column, or Q=1 to reproduce the dew column.
Related
- R404A data sheet: basic identifiers and thermodynamic context.
- R407C PT chart (bubble/dew): a zeotropic blend with noticeable glide.
- R507A PT chart: a blend often treated as (near-)azeotropic (bubble and dew nearly overlap).