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R-454B PT Chart

Saturation pressure for R-454B from -38°F to 150°F, with liquid (bubble) and vapor (dew) columns. Look up a pressure or temperature, switch to metric, and check typical operating pressures.

By BrazeJobs Team · Updated

R-454B Lookup

Liquid (Bubble)

113.3 psig

Vapor (Dew)

107.7 psig

Bubble Point

37.5°F

Dew Point

40.1°F

Chart range: -38°F to 150°F. Enter vacuum as a negative pressure. Check R-454B superheat and subcooling

R-454B PT Chart

TempLiquid (Bubble)Vapor (Dew)
-38°F11.2 psig10.0 psig
-36°F12.5 psig11.2 psig
-34°F13.8 psig12.5 psig
-32°F15.3 psig13.9 psig
-30°F16.7 psig15.3 psig
-28°F18.2 psig16.7 psig
-26°F19.8 psig18.2 psig
-24°F21.4 psig19.8 psig
-22°F23.1 psig21.4 psig
-20°F24.9 psig23.0 psig
-18°F26.7 psig24.8 psig
-16°F28.6 psig26.6 psig
-14°F30.5 psig28.4 psig
-12°F32.5 psig30.3 psig
-10°F34.6 psig32.3 psig
-8°F36.7 psig34.4 psig
-6°F39.0 psig36.5 psig
-4°F41.2 psig38.7 psig
-2°F43.6 psig40.9 psig
0°F46.1 psig43.3 psig
2°F48.6 psig45.7 psig
4°F51.2 psig48.1 psig
6°F53.8 psig50.7 psig
8°F56.6 psig53.3 psig
10°F59.5 psig56.1 psig
12°F62.4 psig58.9 psig
14°F65.4 psig61.8 psig
16°F68.5 psig64.7 psig
18°F71.7 psig67.8 psig
20°F75.0 psig70.9 psig
22°F78.4 psig74.2 psig
24°F81.8 psig77.5 psig
26°F85.4 psig80.9 psig
28°F89.1 psig84.4 psig
30°F92.9 psig88.1 psig
32°F96.8 psig91.8 psig
34°F100.7 psig95.6 psig
36°F104.8 psig99.5 psig
38°F109.0 psig103.6 psig
40°F113.3 psig107.7 psig
42°F117.8 psig112.0 psig
44°F122.3 psig116.3 psig
46°F126.9 psig120.8 psig
48°F131.7 psig125.4 psig
50°F136.6 psig130.1 psig
52°F141.6 psig134.9 psig
54°F146.7 psig139.8 psig
56°F152.0 psig144.9 psig
58°F157.4 psig150.1 psig
60°F162.9 psig155.4 psig
62°F168.6 psig160.8 psig
64°F174.3 psig166.4 psig
66°F180.2 psig172.1 psig
68°F186.3 psig178.0 psig
70°F192.5 psig184.0 psig
72°F198.8 psig190.1 psig
74°F205.3 psig196.4 psig
76°F211.9 psig202.8 psig
78°F218.7 psig209.3 psig
80°F225.6 psig216.1 psig
82°F232.7 psig222.9 psig
84°F239.9 psig229.9 psig
86°F247.3 psig237.1 psig
88°F254.8 psig244.4 psig
90°F262.5 psig251.9 psig
92°F270.4 psig259.6 psig
94°F278.4 psig267.4 psig
96°F286.6 psig275.4 psig
98°F295.0 psig283.6 psig
100°F303.6 psig291.6 psig
105°F325.7 psig313.6 psig
110°F348.9 psig336.4 psig
115°F373.4 psig360.5 psig
120°F399.1 psig385.8 psig
125°F426.0 psig412.4 psig
130°F454.2 psig440.5 psig
135°F483.8 psig470.0 psig
140°F514.9 psig501.0 psig
145°F547.3 psig533.7 psig
150°F581.4 psig568.2 psig

About R-454B

R-454B is an HFC/HFO blend of R-32 and R-1234yf. It is the refrigerant most US manufacturers chose to replace R-410A in new residential and light commercial AC and heat pumps.

It is a zeotropic blend with about 2°F of glide, so the chart gives two columns: liquid (bubble) pressure for subcooling and vapor (dew) pressure for superheat. It runs at slightly lower pressure than R-410A, so reading it on an R-410A chart throws superheat off by several degrees.

  • New residential split AC and heat pumps from 2025, from brands such as Carrier, Trane and Lennox
  • Light commercial packaged and rooftop units
  • Ducted and ductless systems designed for A2L refrigerants

R-454B Properties

Key facts for identifying R-454B and choosing tools, oil and replacements.

Boiling point and critical temperature: Hudson Technologies. GWP: IPCC AR4 values, the basis of EPA’s AIM Act rules. Safety class: ASHRAE Standard 34.
PropertyValue
TypeHFC/HFO blend
CompositionR-32 68.9%, R-1234yf 31.1% by weight
ASHRAE safety classA2L
GWP (IPCC AR4)466
Boiling point at 1 atm-58.9°F
Critical temperature172.6°F
OilPOE (polyolester)
Trade namesOpteon XL41, Solstice 454B, Puron Advance
ReplacesR-410A
Replaced byNone

Typical R-454B Operating Pressures

Suction pressure is the vapor (dew) pressure at the evaporator temperature; head pressure is the liquid (bubble) pressure at the condensing temperature. The temperatures are common design points, not charging targets.

Calculated from the chart on this page. Real pressures move with load, airflow, ambient temperature and charge.
ConditionEvaporatorSuctionCondensingHead
AC cooling, 95°F outdoor40°F107.7 psig115°F373.4 psig

How to Read the R-454B PT Chart

The chart covers -38°F to 150°F. Pressures are gauge pressure (psig), the number your manifold shows; switch to °C and kPa above if you work in metric.

R-454B is a zeotropic blend, so it boils over a range of temperatures instead of at one point. That range is the glide. The liquid (bubble) column gives the pressure where the first bubble forms; the vapor (dew) column gives the pressure where the last drop of liquid boils off.

At 40°F, the bubble pressure is 113.3 psig and the dew pressure is 107.7 psig. Read the other way, at 107.7 psig the glide is about 2.6°F.

Use the vapor (dew) column for superheat on the suction line and the liquid (bubble) column for subcooling on the liquid line. Mixing them up shifts the answer by the glide.

Superheat and Subcooling Formulas

The PT chart turns a gauge pressure into a saturation temperature. Compare that with a line temperature to get superheat or subcooling.

Superheat

SH = Tsuction − Tdew

Subcooling

SC = Tbubble − Tliquid

Vacuum

inHg = −psig × 2.036

Metric

°C = (°F − 32) × 5/9, kPa = psig × 6.895

Tsuction
Suction line temperature near the outdoor unit or compressor, °F
Tliquid
Liquid line temperature leaving the condenser, °F
Tdew
Dew point at suction pressure (vapor column), °F
Tbubble
Bubble point at liquid pressure (liquid column), °F

Gauge pressure (psig) is pressure above atmospheric. Below 0 psig, the chart shows vacuum in inches of mercury.

Worked Example: R-454B Superheat and Subcooling

AC cooling, 95°F outdoor: an R-454B system reads 107.7 psig suction with a 50°F suction line, and 373.4 psig on the liquid line with a 105°F liquid line.

  1. Dew point at 107.7 psig: 40.0°F.
  2. Superheat: 50°F − 40.0°F = 10.0°F.
  3. Bubble point at 373.4 psig: 115.0°F.
  4. Subcooling: 115.0°F − 105°F = 10.0°F.

Result: 10.0°F superheat and 10.0°F subcooling. Compare them with the manufacturer’s targets before adding or recovering refrigerant.

Is R-454B Being Phased Out?

R-454B became common in 2025 when new residential and light commercial AC and heat pumps had to use refrigerants with a GWP under 700. Its GWP of 466 meets that limit.

It is an A2L refrigerant, so systems include leak detection or mitigation where required by UL 60335-2-40, and techs need A2L-rated recovery machines, vacuum pumps and leak detectors.

R-454B Field Tips

Practical points for working on R-454B systems, from the sources below.

  1. 1

    Set the gauge to R-454B

    R-454B runs a few psi below R-410A. A gauge left on R-410A overstates superheat by about 5°F, which can lead to overcharging. Check the nameplate and set the manifold before you read anything.

  2. 2

    Use dew for superheat, bubble for subcooling

    With about 2°F of glide, the column matters. Superheat comes from the vapor (dew) pressure, subcooling from the liquid (bubble) pressure.

  3. 3

    Check A2L tool ratings

    Recovery machines, vacuum pumps and leak detectors that touch the refrigerant need A2L ratings. Cylinders use left-hand threads, so you need the matching adapter.

Sources: Greenheck: A2L refrigerants after the 2025 EPA transition, Ferguson: A2L refrigerant tool compatibility, Chadwell Supply: A2L refrigerant tools and storage, HVAC School: Glide, blends and why you can’t mix refrigerants

Frequently Asked Questions

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