R-407A (HFC, commercial, zeotropic)
R-407A PT Chart
The full R-407A pressure-temperature reference table, from -40 to 130°F on the bubble line, with both the bubble and dew columns its 6.6 to 11.2°F glide requires. Use the dew point for superheat and the bubble point for subcooling. Checked cell by cell against one other published table, a separate publisher: Arkema. Hudson Technologies publishes one too, but its numbers are identical to the table we transcribed from, so it is our own source under another name and is not counted here. It has a full column on file here, so this chart prints where that table and ours disagree at every pressure instead of quietly picking one. The widest gap on the bubble column, which is the one compared here, is 0.19 degrees F, at 114 psig.
Read the R-407A chart at your gauge pressure
The chart below is the reference. This reads it at the pressure you actually have, off the bubble or dew column the line you are measuring calls for, and works out superheat or subcooling once you add the line temperature.
the big insulated line, for superheat
A blend has two saturation temperatures at one pressure. On the suction line the dew point is the one to use. Reading the bubble point instead would put the saturation temperature 9.9°F lower, which makes the superheat come out 9.9°F higher than it is.
At 69.3 psig, this is a published row of the table below, not an interpolated value. Glide at this pressure is 9.9°F.
Add the suction line temperature to get superheat from this reading.
R-407A Pressure-Temperature Table
| Pressure (psig) | Bubble °F (subcooling) | Dew °F (superheat) | Publisher spread (°F) |
|---|---|---|---|
| 3.9 | -40°F | -28.8°F | 0.05 |
| 6.4 | -35°F | -23.9°F | 0.07 |
| 9.2 | -30°F | -18.8°F | 0.01 |
| 12.2 | -25°F | -14°F | 0.07 |
| 15.6 | -20°F | -9°F | 0.02 |
| 19.2 | -15°F | -4.1°F | 0.04 |
| 23.2 | -10°F | 0.8°F | 0 |
| 27.5 | -5°F | 5.6°F | 0.04 |
| 32.2 | 0°F | 10.6°F | 0.04 |
| 37.3 | 5°F | 15.5°F | 0.01 |
| 42.8 | 10°F | 20.4°F | 0.01 |
| 48.7 | 15°F | 25.3°F | 0.04 |
| 55.1 | 20°F | 30.2°F | 0.02 |
| 62 | 25°F | 35.1°F | 0.01 |
| 69.3 | 30°F | 39.9°F | 0.02 |
| 77.2 | 35°F | 44.9°F | 0.01 |
| 85.6 | 40°F | 49.7°F | 0 |
| 94.6 | 45°F | 54.6°F | 0 |
| 104 | 50°F | 59.5°F | 0.10 |
| 114 | 55°F | 64.1°F | 0.19 |
| 125 | 60°F | 69.1°F | 0.09 |
| 137 | 65°F | 74.2°F | 0.13 |
| 149 | 70°F | 78.8°F | 0.08 |
| 162 | 75°F | 83.8°F | 0.11 |
| 175 | 80°F | 88.6°F | 0.11 |
| 190 | 85°F | 93.7°F | 0.10 |
| 205 | 90°F | 98.4°F | 0.06 |
| 221 | 95°F | 103.2°F | 0.06 |
| 238 | 100°F | 108.1°F | 0.11 |
| 255 | 105°F | 112.6°F | 0.08 |
| 274 | 110°F | 117.5°F | 0.02 |
| 293 | 115°F | 122.1°F | 0.13 |
| 314 | 120°F | 127°F | 0 |
| 335 | 125°F | 131.7°F | 0.09 |
| 358 | 130°F | 136.6°F | 0.02 |
About the spread column. It is the widest gap in saturation temperature between the published tables we hold, at that pressure, on the bubble column. Across this chart the widest is 0.19°F, at 114 psig. Our table and 1 other published table are compared here: 1 is a separate publisher. A narrow spread means the charts agree, which is not the same as the charts being right: they are all computed from equations of state fitted to lab data, and no field measurement settles it.
- Checked against Arkema Forane 407A, both columns within 0.20 F across all 35 shipped rows [separate publisher]
- Checked against Hudson Technologies R-407A chart, identical at every row it prints, on both columns [same model]
The base chart annotates one cell, the -40 F vapour pressure, with an inch mark for inches of mercury vacuum, which is the convention its Hudson reprint states in a footer legend. That cell is therefore not a gauge pressure and is left out of the column the dew points are read from. The -40 F row itself does ship, because a row is built from the liquid cell and never from its own vapour cell. The 135 and 140 F rows are not shipped, because their liquid pressures sit above the end of the base's own vapour column and a dew point there would have to be extrapolated.
Hudson Technologies publishes an R-407A chart too, but its numbers are identical to our base at every row it prints, on both columns, so it is one printing under two names and cannot check the table it is a copy of. It is recorded rather than dropped, and it is not counted as a second table. Arkema is the one genuinely separate publisher here, and it agrees to within 0.20 degrees F on both the bubble and the dew column. Our base states no equation of state, so nothing on this page claims a second model, only a second publisher.
A separate publisher can catch a transcription, edition or rounding error. A cross-check marked same model resolves to the same equation of state as the base table, so it is a consistency check rather than independent confirmation. One marked same printing prints numbers identical to another table listed here, so the two are one witness and we do not count them twice. Sources last re-verified 2026-08-25.
Read the low-side (suction) pressure and its dew temperature for superheat, and the high-side (liquid) pressure and its bubble temperature for subcooling. The chart is in psig (gauge) and °F. To convert: kPa gauge = psig × 6.895; °C = (°F − 32) / 1.8.
R-407A PT Chart FAQs
What is the R-407A pressure at a 40F bubble point?
On the R-407A PT chart, a 40F bubble point corresponds to about 85.6 psig, where the dew point is 49.7F. At 205 psig the bubble point is 90F and the dew point is 98.4F. R-407A is a zeotropic R-22 and R-404A replacement for medium and low temperature commercial refrigeration, with a 6.6 to 11.2F glide.
Why does the R-407A PT chart have two temperature columns?
R-407A is a zeotropic blend of R-32, R-125 and R-134a, so at any given pressure it boils and condenses across a range of temperatures rather than at one point. The lower temperature is the bubble point and the higher one is the dew point; the gap is the glide, 6.6 to 11.2 degrees F for R-407A across this table and widest at the cold end. The chart lists both columns so you read the correct one for each measurement.
Do I use bubble or dew point for R-407A superheat and subcooling?
Use the dew point for superheat and the bubble point for subcooling. Superheat is measured on the suction line where the refrigerant is fully vapor, which is the dew side. Subcooling is measured on the liquid line where it is fully liquid, which is the bubble side. Because R-407A glides 6.6 to 11.2 degrees F, using the wrong column introduces a large error, enough to misdiagnose a low temperature rack charge.
How is R-407A different from R-407C?
They share the same three components, R-32, R-125 and R-134a, in different proportions: R-407A is 20/40/40 by weight against R-407C's 23/25/52. R-407A is the one aimed at systems that ran R-404A, and it substitutes for R-404A without matching it: Chemours tabulates R-407A at 0.89 of R-404A's capacity at medium temperature and 0.86 at low temperature, with a compressor discharge temperature of 196F where R-404A runs 154F. R-407C, with more R-134a, is the R-22 comfort cooling replacement. Their PT curves are different, so read the chart for the refrigerant actually in the system.
What units is this R-407A PT chart in, and how do I convert to kPa or Celsius?
The table is in psig (gauge pressure) and degrees Fahrenheit, the field-standard units in North America. To convert pressure to kPa (gauge), multiply psig by 6.895. To convert temperature to Celsius, use C = (F - 32) / 1.8.
Related HVAC Tools
Superheat & Subcooling Calculator
Enter your R-407A readings; the calculator splits bubble and dew for you and returns the verdict.
R-407C PT Chart
The same three components in different proportions, used as an R-22 comfort cooling replacement.
R-404A PT Chart
The refrigerant R-407A replaces on low temperature racks, read on a single saturation column.
Keep going