HVAC PT ChartsVerified saturation data · 61 refrigerants
RefrigerantASHRAE R-422B

R-422B

A1Non-flammableHFC blend AIM Act phase-down
R-125/R-134a/R-600a (55/42/3)

Ternary HFC blend with hydrocarbon (55% R-125 / 42% R-134a / 3% R-600a). A1 safety class, GWP 2526. Mineral-oil-compatible R-22 retrofit for medium-temperature applications. Less commonly deployed than R-422A or R-422D in practice.

Saturation @ 70°F
123.5 / 110.0PSIG
GWP (IPCC AR5)
2526100-yr
Temperature glide
7.6°F
Boiling point
-42.6°F
A1
Non-flammable

Lower toxicity (Occupational Exposure Limit ≥ 400 ppm). No flame propagation in air at standard atmospheric pressure and 60°C. R-134a, R-22, R-410A, R-404A, R-744 (CO2) are A1.

Flammability
None (no flame propagation)
Toxicity
Lower (OEL ≥ 400 ppm)

Classification per ANSI/ASHRAE Standard 34-2022. See full reference.

01

Saturation pressure-temperature curve

Pressure
Temperature
°F
70°F: 123.5 PSIG (bubble)110.0 PSIG (dew)
Quick lookup — R-422B
123.5 / 110.0PSIG(851 / 759 kPa)
Bubble Dew· zeotropic blend
Range: -40 to 150°FOpen full PT calculator →
Common service temperatures
32°F
59 / 49PSIG
Freezing
45°F
78 / 66PSIG
Heat-pump heat
70°F
123 / 110PSIG
Standard
75°F
134 / 121PSIG
Test ref
80°F
146 / 132PSIG
Warm
95°F
185 / 169PSIG
Summer peak

Saturation values from CoolProp 7.2.0 R422B.mix. Operating pressure on a running system differs — see the operating-pressure references for in-use values.

02

R-422B PT chart PDF — printable saturation table

Looking for the R-422B PT chart PDF for shop reference? The complete pressure-temperature saturation table is below — every 1° increment from −40°F to 150°F (or to the refrigerant's critical temperature). Use the Print / Save as PDF button in the table header to download a clean, table-only PDF (the rest of the page is hidden from the print output). Important service temperatures (normal boiling point, freezing point of water, residential AC evap and condenser targets) are tinted and tagged in the table for at-a-glance shop reference.

R-422B PT Chart — Pressure-Temperature Saturation Table

1° increments · Source: CoolProp 7.2.0 / manufacturer datasheet · hvacptcharts.com

R-422B · 1° increments · °F / PSIG
Tinted rows: 32°F H₂O freeze · 40°F AC evap target · 70°F Room T · 95°F AHRI design ambient · 110°F Typical cond saturation
R-422B pressure-temperature saturation table in Fahrenheit and PSIG
Temp (°F)Bubble (PSIG)Dew (PSIG)Glide (PSI)
-40°F1.0-2.73.7
-39°F1.4-2.43.8
-38°F1.9-2.03.9
-37°F2.3-1.73.9
-36°F2.7-1.34.0
-35°F3.1-0.94.1
-34°F3.6-0.64.1
-33°F4.0-0.24.2
-32°F4.50.24.3
-31°F5.00.64.4
-30°F5.51.14.4
-29°F6.01.54.5
-28°F6.51.94.6
-27°F7.02.34.7
-26°F7.52.84.7
-25°F8.03.24.8
-24°F8.63.74.9
-23°F9.14.25.0
-22°F9.74.75.0
-21°F10.35.25.1
-20°F10.95.75.2
-19°F11.46.25.3
-18°F12.16.75.3
-17°F12.77.35.4
-16°F13.37.85.5
-15°F13.98.35.6
-14°F14.68.95.7
-13°F15.29.55.8
-12°F15.910.15.8
-11°F16.610.75.9
-10°F17.311.36.0
-9°F18.011.96.1
-8°F18.712.56.2
-7°F19.413.26.3
-6°F20.213.86.3
-5°F20.914.56.4
-4°F21.715.26.5
-3°F22.515.96.6
-2°F23.316.66.7
-1°F24.117.36.8
0°F24.918.06.9
1°F25.718.86.9
2°F26.619.57.0
3°F27.420.37.1
4°F28.321.17.2
5°F29.221.97.3
6°F30.122.77.4
7°F31.023.57.5
8°F31.924.47.6
9°F32.925.27.7
10°F33.826.17.8
11°F34.826.97.8
12°F35.827.87.9
13°F36.828.88.0
14°F37.829.78.1
15°F38.830.68.2
16°F39.931.68.3
17°F40.932.58.4
18°F42.033.58.5
19°F43.134.58.6
20°F44.235.58.7
21°F45.436.68.8
22°F46.537.68.9
23°F47.638.79.0
24°F48.839.89.1
25°F50.040.99.2
26°F51.242.09.3
27°F52.543.19.4
28°F53.744.29.5
29°F55.045.49.6
30°F56.246.69.6
31°F57.547.89.7
32°FH₂O freeze58.849.09.8
33°F60.250.29.9
34°F61.551.510.0
35°F62.952.810.1
36°F64.354.010.2
37°F65.755.310.3
38°F67.156.710.4
39°F68.558.010.5
40°FAC evap target70.059.410.6
41°F71.560.810.7
42°F73.062.210.8
43°F74.563.610.9
44°F76.065.011.0
45°F77.666.511.1
46°F79.268.011.2
47°F80.869.511.3
48°F82.471.011.4
49°F84.072.511.5
50°F85.774.111.6
51°F87.375.711.7
52°F89.177.311.8
53°F90.878.911.9
54°F92.580.612.0
55°F94.382.212.1
56°F96.183.912.1
57°F97.985.612.2
58°F99.787.412.3
59°F101.689.112.4
60°F103.490.912.5
61°F105.392.712.6
62°F107.394.512.7
63°F109.296.412.8
64°F111.298.312.9
65°F113.2100.213.0
66°F115.2102.113.1
67°F117.2104.013.2
68°F119.3106.013.3
69°F121.4108.013.3
70°FRoom T123.5110.013.4
71°F125.6112.113.5
72°F127.8114.113.6
73°F129.9116.213.7
74°F132.2118.313.8
75°F134.4120.513.9
76°F136.6122.714.0
77°F138.9124.914.0
78°F141.2127.114.1
79°F143.6129.314.2
80°F145.9131.614.3
81°F148.3133.914.4
82°F150.7136.314.5
83°F153.2138.614.5
84°F155.6141.014.6
85°F158.1143.414.7
86°F160.6145.814.8
87°F163.2148.314.9
88°F165.8150.814.9
89°F168.4153.315.0
90°F171.0155.915.1
91°F173.7158.515.2
92°F176.3161.115.3
93°F179.1163.715.3
94°F181.8166.415.4
95°FAHRI design ambient184.6169.115.5
96°F187.4171.815.5
97°F190.2174.615.6
98°F193.1177.415.7
99°F196.0180.215.7
100°F198.9183.115.8
101°F201.8186.015.9
102°F204.8188.915.9
103°F207.8191.816.0
104°F210.9194.816.1
105°F213.9197.816.1
106°F217.0200.916.2
107°F220.2204.016.2
108°F223.3207.116.3
109°F226.5210.216.3
110°FTypical cond saturation229.8213.416.4
111°F233.0216.616.4
112°F236.3219.916.5
113°F239.7223.116.5
114°F243.0226.516.5
115°F246.4229.816.6
116°F249.8233.216.6
117°F253.3236.616.7
118°F256.8240.116.7
119°F260.3243.616.7
120°F263.9247.116.8
121°F267.5250.716.8
122°F271.1254.316.8
123°F274.8257.916.8
124°F278.5261.616.9
125°F282.2265.316.9
126°F286.0269.116.9
127°F289.8272.916.9
128°F293.6276.716.9
129°F297.5280.616.9
130°F301.5284.516.9
131°F305.4288.516.9
132°F309.4292.517.0
133°F313.4296.516.9
134°F317.5300.616.9
135°F321.6304.716.9
136°F325.8308.916.9
137°F329.9313.116.9
138°F334.2317.316.9
139°F338.4321.616.9
140°F342.8325.916.8
141°F347.1330.316.8
142°F351.5334.716.7
143°F355.9339.216.7
144°F360.4343.716.7
145°F364.9348.316.6
146°F369.4352.916.6
147°F374.0357.516.5
148°F378.6362.216.4
149°F383.3367.016.3
150°F388.0371.816.3
CoolProp 7.2.0 · PSIG/kPa = gauge · PSIA = PSIG + 14.696 · kPa(abs) = kPa(gauge) + 101.325

Full saturation values at 1° increments — toggle between °F / PSIG and °C / kPa. Use Print / Save as PDF for laminated shop reference, or download the CSV / JSON below for use in other tools. R-422B PT chart data: CoolProp 7.2.0 (REFPROP-compatible Helmholtz EOS) or manufacturer datasheet, validated against AHRI Standard 700-2019.

03

At a glance

Chemistry

R-125/R-134a/R-600a (55/42/3)
Ternary HFC blend with isobutane

Lubricant compatibility

MOABPOE

Mineral-oil-compatible R-22 retrofit. Less common than R-422A or R-422D in practice.

Blend composition

  • R-12555.0%
  • R-134a42.0%
  • R-600a3.0%

Common applications

  • R-22 retrofit (medium-temperature)
  • Commercial AC retrofit
04

Properties

  • Boiling point (1 atm)
    -41.5°C / -42.6°F
  • Critical point
    No single point — blend critical locus
  • Molar mass
    108.52 g/mol
  • Temperature glide
    7.6°F
  • ODP
    0
  • GWP (AR5, 100-yr)
    2526
  • GWP (AR6, 100-yr)
    2710
05

What is R-422B?

R-422B is a ternary HFC blend with a small isobutane (R-600a, hydrocarbon) component. Composition by mass: 55% R-125, 42% R-134a, 3% R-600a. The R-125-R-134a backbone provides medium-temperature capacity matched to R-22; the R-600a addition aids miscibility with mineral oil — allowing R-22 retrofit without the POE oil change that R-410A or R-407C retrofit would demand.

R-422B is part of the broader R-422 family of R-22 retrofit blends: R-422A (low-temp focus, 85% R-125), R-422B (medium-temp, 55% R-125), R-422C (some markets, 82% R-125), R-422D (medium-temp, 65% R-125). R-422B in practice is less commonly deployed than R-422A (better low-temp match) or R-422D (which captures most medium-temp retrofit interest). It exists in the family for capacity-matching specific equipment configurations.

Where R-422B is used

  • R-22 retrofit, medium-temperature applications (commercial AC, light commercial cooling)
  • Existing equipment where mineral oil staying in the system is desirable
  • Service stock for properties where R-422D or R-422A isn't a better capacity match

Regulatory & phase-down status

R-422B is affected by the EPA AIM Act HFC phase-down — its GWP of 2526 is well above the 700-GWP threshold for HVAC equipment. It remains commercially available for service of existing equipment, but as R-22 equipment ages out through replacement cycles, the R-422B retrofit market continues to shrink. For new equipment R-422B is not an option; for legacy R-22 equipment that's worth keeping operational, R-422B and the rest of the R-422 family remain viable until full replacement.

Modern R-22 retrofit guidance increasingly favors full system replacement with R-32 (A2L, GWP 675) or R-454B (A2L, GWP 466) rather than HFC drop-in retrofit, because the new equipment is more efficient and the HFC retrofits face their own AIM Act phase-down.

Service notes

Mineral oil (MO), alkylbenzene (AB), and POE oils are all compatible. The 3% R-600a hydrocarbon component aids mineral oil return — that's the design feature distinguishing R-422 family blends from R-407C (which requires POE oil change). R-422B has substantial temperature glide (~7°F) — use the dew curve for superheat and the bubble curve for subcooling, matching the procedure for any zeotropic blend.

EPA Section 608 Type II or Universal certification covers R-422B. Recovery is required.

06

Temperature glide

Temperature glide across evaporator at constant pressureR-422B at 70 PSIG suction→ refrigerant flow →Entry: 40.0°FMid: 43.7°FExit: 47.3°FGlide = 7.3°FPosition along evaporator coil40°F47°F

R-422B is a zeotropic blend: at constant pressure it boils across a temperature range rather than at a single point. This affects EXV sizing, charge measurement, and superheat measurement. Use the dew curve for superheat, bubble curve for subcooling.

07

Operating cycle

CompressorRaises pressureCondenserRejects heat to outdoorsExpansion deviceDrops pressureEvaporatorAbsorbs heat from indoorsDischarge: 230 PSIG, 180°FLiquid: 230 PSIG, 100°FEvap inlet: 70 PSIG, 40°F (two-phase)Suction: 70 PSIG, 50°FTypical residential cooling cycle for R-422B (40°F evap, 110°F condenser, 10°F superheat, 10°F subcooling)
08

Phase-down timeline

No phase-down milestones documented for R-422B in this build. This may mean: (a) no regulatory phase-down currently published; (b) the refrigerant has local regulatory schedules not yet transcribed into the site dataset; or (c) it is a specialty refrigerant outside the main regulatory frameworks. For authoritative current status, consult the EPA AIM Act allocations (40 CFR Part 84), EU F-Gas Regulation 517/2014 + 2024/573, and the relevant national implementations of the Kigali Amendment.

Properties: GWP (AR5) 2526 · ODP 0 · AIM Act affected · type: hfc-blend
09

Global warming potential, in context

R-22 retrofit blends

R-407C1.8kR-221.8kR-427A2.1kR-438A2.3kR-417A2.3kR-422B2.5kR-421A2.6kR-422D2.7kR-422A3.1kEU F-Gas (150)EPA AIM Act (700)
10

Retrofit and replacement paths

R-422B replaces

11

Frequently asked

What's the difference between R-422A, R-422B, and R-422D?

All three are HFC ternary blends with small hydrocarbon for mineral oil miscibility. R-422A is R-125/R-134a/R-600a at 85.1/11.5/3.4 — low-temperature focus, high R-125 for high vapor pressure. R-422B is 55/42/3 — medium-temperature focus, more R-134a content. R-422D is R-125/R-134a/R-600a at 65.1/31.5/3.4 — between the other two, marketed broadly for medium-temperature AC and refrigeration. R-422D captures most market share in the medium-temperature R-22 retrofit space; R-422A is preferred for low-temperature; R-422B exists as a capacity-specific option.

Why does R-422B have glide while R-422A is closer to azeotropic?

R-422A's 85% R-125 content makes it close to pure R-125 behavior — small fractions of other components produce small glide. R-422B's more balanced 55/42 R-125/R-134a composition spans a wider range of pure-component boiling points (R-125 at -49°C vs R-134a at -26°C), producing larger glide. Larger glide affects how superheat and subcooling are measured (use dew for superheat, bubble for subcooling) but does not preclude use in equipment originally designed for azeotropic refrigerants.

What lubricant does R-422B use?

Mineral oil (MO), alkylbenzene (AB), and POE are all compatible. For R-22 to R-422B retrofit, mineral oil typically stays in the system — that's the design intent. The 3% R-600a component aids HFC-mineral-oil miscibility that would otherwise be poor for a 55/42 R-125/R-134a blend alone.

Should I retrofit to R-422B or do a full system replacement?

Decision factors: (1) equipment age — over 15 years and full replacement is usually more cost-effective; (2) leak history — multiple leaks point to system condition issues that retrofit won't fix; (3) future-proofing — R-422B faces its own AIM Act phase-down, so retrofit buys time but not permanently; (4) energy cost differential — new R-32 or R-454B equipment is ~20-30% more efficient than R-22 era equipment. For systems under 10 years with no leaks where capital is constrained, R-422B retrofit is reasonable. For older systems, replace.

What is the GWP of R-422B?

2526 per IPCC AR5, mass-weighted from components: R-125 (3500) at 55%, R-134a (1430) at 42%, R-600a (3) at 3%. This is well above the AIM Act 700-GWP threshold for new equipment but adequate-to-better than R-22's GWP 1810 (though R-22 has ODP, which R-422B does not — different concerns).

Download this dataset

Full PT chart for R-422B · CC BY 4.0 · attribute the source

Data sources & provenance

PT chart
CoolProp 7.2.0 R422B.mix
Cross-checked against
CoolProp 7.2.0 (R422B.mix)
Properties
CoolProp 7.2.0 + ASHRAE Standard 34-2022
GWP
IPCC AR5 Table 8.A.1 (composition-weighted)
Generated
2026-06-12

Reference material. Always verify pressure values against the equipment data plate and manufacturer service literature before charging or troubleshooting a specific system. Saturation pressure differs from operating pressure — see superheat & subcooling fundamentals.