R-407C (HFC, zeotropic blend)

R-407C PT Chart

The full R-407C pressure-temperature reference table, from -20 to 130°F, with both the bubble and dew columns its 7.7 to 12.4°F glide requires. Use the dew point for superheat and the bubble point for subcooling. Checked cell by cell against 2 other published tables, all of them separate publishers: Arkema and Honeywell. One of them, Arkema, 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 0.57 degrees F, against Arkema, at 14.1 psig. Print it or save it as a PDF for the truck.

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Quick answer: R-407C is zeotropic, so it lists two saturation temperatures at each pressure. At 226 psig the bubble point is 100°F (use for subcooling) and the dew point is 109.2°F (use for superheat), a glide of about 7.7 to 12.4°F. Read the dew point for superheat and the bubble point for subcooling, or the glide will skew the reading.

Read the R-407C 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.

Refrigerant

Which line is the reading from

the big insulated line, for superheat

Gauge pressure

Line temperature optional, for superheat

Saturation temperature dew point, the column superheat uses41.4°F

The other column bubble point, which subcooling uses30.0°F

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 11.4°F lower, which makes the superheat come out 11.4°F higher than it is.

At 65.2 psig, this is a published row of the table below, not an interpolated value. Glide at this pressure is 11.4°F.

Add the suction line temperature to get superheat from this reading.

R-407C Pressure-Temperature Table

R-407C saturation temperatures at gauge pressure (psig): bubble (subcooling) and dew (superheat).
R-407C
Pressure (psig)	Bubble °F (subcooling)	Dew °F (superheat)	Publisher spread (°F)
14.1	-20°F	-7.6°F	0.57
17.6	-15°F	-2.7°F	0.54
21.3	-10°F	2.1°F	0.49
25.4	-5°F	7°F	0.44
29.9	0°F	12°F	0.42
34.7	5°F	16.8°F	0.38
39.9	10°F	21.7°F	0.35
45.6	15°F	26.7°F	0.33
51.6	20°F	31.5°F	0.31
58.2	25°F	36.5°F	0.36
65.2	30°F	41.4°F	0.33
72.6	35°F	46.2°F	0.25
80.7	40°F	51.2°F	0.29
89.2	45°F	56°F	0.22
98.3	50°F	60.8°F	0.21
108	55°F	65.9°F	0.19
118	60°F	70.5°F	0
129	65°F	75.4°F	0.04
141	70°F	80.4°F	0.20
153	75°F	85°F	0.08
166	80°F	90°F	0.07
180	85°F	94.7°F	0.14
195	90°F	99.7°F	0.29
210	95°F	104.7°F	0.19
226	100°F	109.2°F	0.15
243	105°F	113.9°F	0.17
261	110°F	118.7°F	0.19
280	115°F	123.5°F	0.26
300	120°F	128.3°F	0.34
321	125°F	133.2°F	0.42
342	130°F	137.7°F	0.29

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 0.57°F, at 14.1 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.

Where this table comes from. Hudson Technologies R-407C liquid and vapor chart, bubble and dew.

Checked against Arkema Forane R-407C, all 31 bubble cells within 2.0 psig, widest gap 1.8 psig at 125F, and all 31 dew points within 0.5 F; re-derived in DEGREES, the quantity the calculator publishes, the bubble column differs by at most 0.58 F and the dew column by at most 0.36 F [separate publisher]
Checked against Honeywell Genetron 407C, bubble and dew anchors agree [separate 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.

These are the same locked R-407C bubble and dew data the Intry calculator interpolates, with full glide handling. The published tables they were checked against, and how closely each agrees, are named in the citation that prints with the chart above. Free reference from intrysys.com, updated August 25, 2026.

R-407C PT Chart FAQs

Why does the R-407C PT chart have two temperature columns?

R-407C is a zeotropic blend, 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 between them is the glide, about 7.7 to 12.4 degrees F for R-407C over typical operating conditions, widening toward the cold, low-pressure end of the chart. At 226 psig, for example, the bubble point is 100F and the dew point is 109.2F.

Do I use bubble or dew point for R-407C 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, so convert suction pressure to the dew temperature. Subcooling is measured on the liquid line where the refrigerant is fully liquid, which is the bubble side, so convert liquid pressure to the bubble temperature. Using the wrong column introduces an error equal to the glide, roughly 7.7 to 12.4 degrees F, which is enough to misdiagnose the charge.

What is the R-407C pressure at a 70F bubble point?

On the R-407C PT chart, a 70F bubble point corresponds to about 141 psig, where the dew point is 80.4F. R-407C is the common R-22 retrofit blend, so its pressures sit close to R-22 on a service gauge, but the glide means you must read the correct column for each measurement.

What units is this R-407C 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

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Printable Superheat & Subcooling Chart

Target ranges by refrigerant plus PT charts for R-410A, R-454B, and R-22, formatted to print or save as a PDF.

Intry Verified. The R-407C bubble and dew pressure-temperature columns and their anchors on this page are the locked, second-sourced R-407C PT data, and every build re-checks the page against those locked values. Those figures are computed by a locked engine straight from the source it cites, not hand-typed, and that computation re-runs inside a deterministic test on every deploy. Source-checked. Locked. This is our own deterministic gate, not a third-party audit. What Intry Verified means

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