HVAC PT Charts
RefrigerantASHRAE R-422D

R422D PT Chart

Updated October 12, 2026

R-422D

A1 Lower toxicity, no flame propagationHFC blend AIM Act HFC
R-422D AHRI Guideline N service cylinderIllustration of a refrigerant cylinder painted light green gray (RAL 7044), the color AHRI Guideline N-2017 calls for on all new refrigerant containers from 2020. Label: R422D, safety class A1, GWP 2,729. No red band: AHRI Guideline N-2017 reserves it for flammable refrigerants.R422DA1GWP 2,729
Illustration of a refrigerant cylinder painted light green gray (RAL 7044), the color AHRI Guideline N-2017 calls for on all new refrigerant containers from 2020[5], section 4.8. Label: R-422D, safety class A1, GWP 2,729. No red band: AHRI Guideline N-2017 reserves it for flammable refrigerants[5], section 4.7.
R-125/R-134a/R-600a (65.1/31.5/3.4)

Ternary HFC blend with small hydrocarbon component (R-125/R-134a/R-600a 65.1/31.5/3.4 mass) marketed as Chemours Freon MO29 (formerly DuPont ISCEON MO29) — A1 safety, GWP 2,729. R-22 retrofit refrigerant designed for mineral-oil compatibility without oil change.

R-422D saturation pressure splits across its glide: dew 66.5 PSIG at 40°F, bubble 213.2 PSIG at 100°F, and 120.9–133.3 PSIG dew-to-bubble at 70°F. Use the dew column for superheat and the bubble column for subcooling. The full table below runs from −40°F to 150°F in 1°F steps.

Not yet checked against an independent source.

Saturation @ 70°F
133.3 / 120.9 PSIG
GWP (100-yr)
2,729 US EPA value, 40 CFR 84.64(b)
Temperature glide
6.6°F
Boiling point
bubble −46.1°F / dew −37.0°F
Sourced facts
ASHRAE safety class
A1[1]
Composition (mass)
65.1% R-125 / 31.5% R-134a / 3.4% R-600a[1]
GWP (100-yr)
2,729
ODP
0[1]
Normal boiling point
bubble −46.1°F (−43.4°C), dew −37.0°F (−38.4°C)[3]
Temperature glide
6.6°F at a 40°F dew point[3]
Lubricant
MO / AB / POE
Trade name
Freon MO29[4]
R-422D PT calculator Superheat

R-422D PT chart — printable saturation table

Looking for the R-422D 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).

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

Computed with CoolProp 7.2.0 in 1°F steps · hvacptcharts.com

R-422D · 1° increments · °F / PSIG
Tinted rows: 32°F H₂O freeze
R-422D pressure-temperature saturation table in Fahrenheit and PSIG
Temp (°F)Bubble (PSIG)Dew (PSIG)
−40°F 2.52.3 in. Hg vac.
−39°F 2.91.6 in. Hg vac.
−38°F 3.40.8 in. Hg vac.
−37°F 3.90.0
−36°F 4.30.4
−35°F 4.80.8
−34°F 5.31.2
−33°F 5.81.7
−32°F 6.32.1
−31°F 6.82.6
−30°F 7.33.0
−29°F 7.93.5
−28°F 8.44.0
−27°F 9.04.4
−26°F 9.54.9
−25°F 10.15.4
−24°F 10.76.0
−23°F 11.36.5
−22°F 11.97.0
−21°F 12.57.6
−20°F 13.18.1
−19°F 13.88.7
−18°F 14.49.3
−17°F 15.19.9
−16°F 15.810.5
−15°F 16.411.1
−14°F 17.111.7
−13°F 17.912.3
−12°F 18.613.0
−11°F 19.313.6
−10°F 20.114.3
−9°F 20.815.0
−8°F 21.615.7
−7°F 22.416.4
−6°F 23.217.1
−5°F 24.017.8
−4°F 24.818.6
−3°F 25.619.3
−2°F 26.520.1
−1°F 27.420.9
0°F 28.221.7
1°F 29.122.5
2°F 30.023.3
3°F 31.024.2
4°F 31.925.0
5°F 32.825.9
6°F 33.826.8
7°F 34.827.7
8°F 35.828.6
9°F 36.829.5
10°F 37.830.4
11°F 38.931.4
12°F 39.932.4
13°F 41.033.4
14°F 42.134.4
15°F 43.235.4
16°F 44.336.4
17°F 45.437.5
18°F 46.638.5
19°F 47.839.6
20°F 48.940.7
21°F 50.241.8
22°F 51.443.0
23°F 52.644.1
24°F 53.945.3
25°F 55.146.5
26°F 56.447.7
27°F 57.748.9
28°F 59.150.2
29°F 60.451.4
30°F 61.852.7
31°F 63.254.0
32°F H₂O freeze64.655.3
33°F 66.056.6
34°F 67.458.0
35°F 68.959.4
36°F 70.360.7
37°F 71.862.2
38°F 73.463.6
39°F 74.965.0
40°F 76.566.5
41°F 78.068.0
42°F 79.669.5
43°F 81.271.0
44°F 82.972.6
45°F 84.574.2
46°F 86.275.8
47°F 87.977.4
48°F 89.679.0
49°F 91.480.7
50°F 93.282.4
51°F 94.984.1
52°F 96.785.8
53°F 98.687.5
54°F 100.489.3
55°F 102.391.1
56°F 104.292.9
57°F 106.194.8
58°F 108.196.6
59°F 110.198.5
60°F 112.0100.4
61°F 114.1102.4
62°F 116.1104.3
63°F 118.2106.3
64°F 120.3108.3
65°F 122.4110.3
66°F 124.5112.4
67°F 126.7114.5
68°F 128.9116.6
69°F 131.1118.7
70°F 133.3120.9
71°F 135.6123.1
72°F 137.9125.3
73°F 140.2127.5
74°F 142.5129.8
75°F 144.9132.1
76°F 147.3134.4
77°F 149.7136.8
78°F 152.1139.1
79°F 154.6141.5
80°F 157.1144.0
81°F 159.6146.4
82°F 162.2148.9
83°F 164.8151.4
84°F 167.4154.0
85°F 170.0156.5
86°F 172.7159.2
87°F 175.4161.8
88°F 178.1164.4
89°F 180.9167.1
90°F 183.7169.9
91°F 186.5172.6
92°F 189.3175.4
93°F 192.2178.2
94°F 195.1181.1
95°F 198.0183.9
96°F 201.0186.8
97°F 204.0189.8
98°F 207.0192.8
99°F 210.1195.8
100°F 213.2198.8
101°F 216.3201.9
102°F 219.4205.0
103°F 222.6208.1
104°F 225.8211.3
105°F 229.1214.5
106°F 232.4217.7
107°F 235.7221.0
108°F 239.0224.3
109°F 242.4227.7
110°F 245.8231.0
111°F 249.3234.5
112°F 252.8237.9
113°F 256.3241.4
114°F 259.8244.9
115°F 263.4248.5
116°F 267.0252.1
117°F 270.7255.7
118°F 274.4259.4
119°F 278.1263.1
120°F 281.9266.9
121°F 285.7270.6
122°F 289.5274.5
123°F 293.4278.3
124°F 297.3282.2
125°F 301.2286.2
126°F 305.2290.2
127°F 309.2294.2
128°F 313.3298.3
129°F 317.4302.4
130°F 321.5306.5
131°F 325.7310.7
132°F 329.9315.0
133°F 334.2319.3
134°F 338.5323.6
135°F 342.8328.0
136°F 347.2332.4
137°F 351.6336.8
138°F 356.1341.3
139°F 360.6345.9
140°F 365.1350.5
141°F 369.7355.1
142°F 374.4359.8
143°F 379.0364.6
144°F 383.7369.4
145°F 388.5374.2
146°F 393.3379.1
147°F 398.2384.0
148°F 403.0389.0
149°F 408.0394.1
150°F 413.0399.2
CoolProp 7.2.0 · PSIG/kPa = gauge · PSIA = PSIG + 14.6959 · 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-422D PT chart data: CoolProp 7.2.0 (published Helmholtz equations of state / mixture models — see the source citations above).

A1
Lower toxicity, no flame propagation

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[1], safety group definitions and refrigerant safety classifications. See full reference.

Saturation pressure-temperature curve

Pressure
Temperature
°F
70°F: 133.3 PSIG (bubble)120.9 PSIG (dew)
Quick lookup — R-422D
133.3 / 120.9PSIG(919 / 834 kPa)
Bubble Dew· zeotropic blend
Range: −40 to 150°F Open full PT calculator →
Common service temperatures
32°F
65 / 55PSIG
Freezing
45°F
85 / 74PSIG
Heat-pump heat
70°F
133 / 121PSIG
Standard
75°F
145 / 132PSIG
Test ref
80°F
157 / 144PSIG
Warm
95°F
198 / 184PSIG
Summer peak

Saturation values from CoolProp 7.2.0 mixture model: R-125/R-134a/R-600a, 65.1/31.5/3.4% by mass[3]. Operating pressure on a running system differs — see the operating-pressure references for in-use values.

At a glance

Chemistry

R-125/R-134a/R-600a (65.1/31.5/3.4)
Ternary HFC blend with isobutane

Lubricant compatibility

MOABPOE

Mineral-oil-compatible R-22 retrofit. A medium-temperature retrofit option for commercial AC where oil change is impractical.

Blend composition

  • R-125 65.1%
  • R-134a 31.5%
  • R-600a 3.4%

Trade names

  • ISCEON MO29 — Chemours

Common applications

  • R-22 retrofit (medium-temperature commercial AC)
  • Heat pumps (legacy retrofit)

Properties

  • Boiling point (1 atm)
    bubble −46.1°F (−43.4°C), dew −37.0°F (−38.4°C)
  • Critical point
    No single point — blend critical locus
  • Molar mass
    109.94 g/mol
  • Temperature glide
    6.6°F
  • ODP
    0
  • GWP (100-yr)
    2,729 US EPA value, 40 CFR 84.64(b) IPCC: AR4 not assessed · AR5 not assessed · AR6 not assessed
  • New-equipment status (US)
    Restricted in 48 new-equipment categories — US new-equipment rules (40 CFR 84.54).

What is R-422D?

R-422D is a ternary HFC blend with a small hydrocarbon (R-600a isobutane) component: R-125 (65.1%) + R-134a (31.5%) + R-600a (3.4%) by mass[1].

Chemours markets R-422D as Freon MO29 (originally DuPont ISCEON MO29) — the "MO" referring to "mineral oil" compatibility. The 3.4% R-600a isn't enough to change the A1 safety classification (R-600a is A3 individually but the blend's non-flammable HFC majority dominates), but it's enough to enable R-22 mineral oil retention through retrofit[4].

Where R-422D is used

  • R-22 retrofit in residential and light commercial AC where oil change is undesirable
  • R-22 retrofit in commercial refrigeration applications
  • Service refrigerant for existing R-22 equipment
  • Heat pump retrofit from R-22

Regulatory & phase-down status

R-422D faces AIM Act phase-down pressure due to its high GWP (2,729)[2]. The blend is acceptable for R-22 retrofit but not specified for new equipment installations.

For service of existing R-22 retrofits, R-422D remains available for servicing existing systems under EPA Section 608 rules.

Service notes

Mineral oil, alkylbenzene, or POE all compatible — the primary retrofit advantage.

The 7°F glide affects service measurement — use dew curve for superheat, bubble curve for subcooling. A1 classification means no A2L procedures required.

Temperature glide

Temperature glide across evaporator at constant pressureR-422D at 76 PSIG suction→ refrigerant flow →Entry: 40.0°F Mid: 43.2°F Exit: 46.4°F Glide = 6.4°F Position along evaporator coil40°F 46°F

R-422D is a zeotropic blend: at constant pressure it boils across a temperature range rather than at a single point. Use the dew curve for superheat, bubble curve for subcooling.

Operating cycle

CompressorRaises pressureCondenserRejects heat to outdoorsExpansion deviceDrops pressureEvaporatorAbsorbs heat from indoorsDischarge: 246 PSIG, 180°F Liquid: 246 PSIG, 100°F Evap inlet: 67 PSIG, 40°F (two-phase)Suction: 67 PSIG, 50°F Example cycle for R-422D (40°F evap, 110°F condenser, 10°F superheat, 10°F subcooling)

Phase-down timeline

R-422D contains HFC-125 and HFC-134a, regulated substances under the AIM Act. Its GWP under 40 CFR 84.64 is 2,729, at or above the limit in 48 of the categories 40 CFR 84.54 restricts (listed under “All 84.54 categories restricting R-422D”).

  • From January 1, 2025 — new self-contained residential & light-commercial AC and heat pump products: manufacture / import restricted (GWP ≥ 700)[2], §84.54(a)(1).
  • From January 1, 2025 — new residential & light-commercial AC and heat pump systems (except VRF): installation restricted (GWP ≥ 700), unless every specified component was manufactured or imported before January 1, 2025[2], §84.54(c)(1).
  • From January 1, 2026 — new variable refrigerant flow (VRF) residential & light-commercial AC and heat pump systems: installation restricted (GWP ≥ 700); systems whose specified components were all manufactured or imported before January 1, 2026 may be installed until January 1, 2027, or until January 1, 2028 when a building permit issued before October 5, 2023 specifies the refrigerant[2], §84.54(c)(2).
  • From January 1, 2028 — new self-contained residential & light-commercial AC and heat pump products: sale and distribution restricted (GWP ≥ 700)[2], §84.54(b).

HFC production & consumption allowances step down to 30% of baseline in 2029–2033, 20% of baseline in 2034–2035, and 15% of baseline in 2036 and later (42 U.S.C. 7675(e)(2)(C)).

Full 40 CFR 84.54 new-equipment rules for R-422D →

US new-equipment rules (40 CFR 84.54)

R-422D contains HFC-125 and HFC-134a, regulated substances under the AIM Act. Under 40 CFR 84.64(b) its GWP is 2,729: each component's GWP times its mass fraction; components without a GWP under 84.64 are left out (84.64(c)). That value is compared against each 40 CFR 84.54 subsector limit below.

EffectiveEquipment subsectorLimitRestriction
January 1, 2025Self-contained residential & light-commercial AC and heat pump productsGWP ≥ 700Manufacture / import(a)(1)
January 1, 2025Residential & light-commercial AC and heat pump systems (except VRF)GWP ≥ 700Installation(c)(1)
January 1, 2026Variable refrigerant flow (VRF) residential & light-commercial AC and heat pump systemsGWP ≥ 700Installation(c)(2)
January 1, 2028Self-contained residential & light-commercial AC and heat pump productsGWP ≥ 700Sale / distribution(b)
All 84.54 categories restricting R-422D (48)[2]
Refrigeration, air conditioning & heat pumps (41)
January 1, 2025Self-contained residential & light-commercial AC and heat pump productsGWP ≥ 700(a)(1)
January 1, 2025Chillers for comfort coolingGWP ≥ 700(a)(10)(i)
January 1, 2025Chillers for ice rinksGWP ≥ 700(a)(10)(ii)
January 1, 2025Residential dehumidifiersGWP ≥ 700(a)(2)
January 1, 2025Household refrigerators and freezersGWP ≥ 150(a)(3)
January 1, 2025Retail food refrigeration — stand-alone unitsGWP ≥ 150(a)(4)
January 1, 2025Vending machinesGWP ≥ 150(a)(5)
January 1, 2025Refrigerated transport — road and marine (self-contained products)listed refrigerant(a)(7)
January 1, 2025Residential & light-commercial AC and heat pump systems (except VRF)GWP ≥ 700(c)(1)
January 1, 2025Chillers for comfort coolingGWP ≥ 700(c)(3)
January 1, 2025Ice rinksGWP ≥ 700(c)(4)
January 1, 2025Refrigerated transport — road or marine systemslisted refrigerant(c)(8)
January 1, 2026Chillers for industrial process refrigeration, fluid exiting the chiller warmer than −22°F (−30°C)GWP ≥ 700(a)(10)(iii)
January 1, 2026Industrial process refrigeration products (non-chiller), charge 200 lb or greater, refrigerant entering the evaporator warmer than −22°F (−30°C)GWP ≥ 150(a)(12)(i)
January 1, 2026Industrial process refrigeration products (non-chiller), charge less than 200 lb, refrigerant entering the evaporator warmer than −22°F (−30°C)GWP ≥ 300(a)(12)(ii)
January 1, 2026Ice makers — batch type up to 1,000 lb of ice per 24 h and continuous type up to 1,200 lb per 24 hGWP ≥ 150(a)(8)(i)
January 1, 2026Industrial process refrigeration systems (non-chiller), charge 200 lb or greater, evaporator inlet warmer than −22°F (−30°C), not the high-temperature side of a cascadeGWP ≥ 150(c)(10)(i)
January 1, 2026Industrial process refrigeration systems (non-chiller), charge less than 200 lb, evaporator inlet warmer than −22°F (−30°C)GWP ≥ 300(c)(10)(ii)
January 1, 2026Industrial process refrigeration — high-temperature side of cascade systems, evaporator inlet warmer than −22°F (−30°C)GWP ≥ 300(c)(10)(iii)
January 1, 2026Variable refrigerant flow (VRF) residential & light-commercial AC and heat pump systemsGWP ≥ 700(c)(2)
January 1, 2026Chillers for industrial process refrigeration, fluid exiting the chiller warmer than −22°F (−30°C)GWP ≥ 700(c)(5)(i)
July 27, 2026Refrigerated transport — intermodal containers with a box temperature of −31°F (−35°C) or higherGWP ≥ 700(a)(6)
July 27, 2026Retail food refrigeration — remote condensing unitsGWP ≥ 1,400(c)(11)(i)
July 27, 2026Refrigerated transport — intermodal containers with a box temperature of −31°F (−35°C) or higherGWP ≥ 700(c)(7)
July 27, 2026Cold storage warehouse systemsGWP ≥ 700(c)(9)(i)
January 1, 2027Self-contained products in data center, information technology equipment facility, and computer room coolingGWP ≥ 700(a)(11)
January 1, 2027Ice makers — batch type above 1,000 lb of ice per 24 h and continuous type above 1,200 lb per 24 hlisted refrigerant(a)(8)(ii)
January 1, 2027Refrigerated food processing and dispensing products outside the scope of UL 621, charge 500 g or lessGWP ≥ 150(a)(9)(i)
January 1, 2027Refrigerated food processing and dispensing products outside the scope of UL 621, charge greater than 500 glisted refrigerant(a)(9)(ii)
January 1, 2027Supermarket systemsGWP ≥ 1,400(c)(12)(i)
January 1, 2027Data center, information technology equipment facility, and computer room cooling systemsGWP ≥ 700(c)(13)
January 1, 2027Automatic commercial ice machines with a remote condenserlisted refrigerant(c)(14)
January 1, 2027Refrigerated food processing and dispensing equipment with a remote condenserlisted refrigerant(c)(15)
January 1, 2028Chillers for industrial process refrigeration, fluid exiting the chiller from −58°F to −22°F (−50°C to −30°C)GWP ≥ 700(a)(10)(iv)
January 1, 2028Industrial process refrigeration products (non-chiller), refrigerant entering the evaporator from −58°F to −22°F (−50°C to −30°C)GWP ≥ 700(a)(12)(iii)
January 1, 2028Refrigerated food processing and dispensing products within the scope of UL 621 (ice cream makers)listed refrigerant(a)(9)(iii)
January 1, 2028Industrial process refrigeration systems (non-chiller), evaporator inlet from −58°F to −22°F (−50°C to −30°C)GWP ≥ 700(c)(10)(iv)
January 1, 2028Chillers for industrial process refrigeration, fluid exiting the chiller from −58°F to −22°F (−50°C to −30°C)GWP ≥ 700(c)(6)(i)
January 1, 2032Retail food refrigeration — remote condensing unitsGWP ≥ 150 (200 lb or greater, not the cascade high side); GWP ≥ 300 (less than 200 lb); GWP ≥ 300 (cascade high side)(c)(11)(ii)
January 1, 2032Supermarket systemsGWP ≥ 150 (200 lb or greater, not the cascade high side); GWP ≥ 300 (less than 200 lb); GWP ≥ 300 (cascade high side)(c)(12)(ii)
January 1, 2032Cold storage warehouse systemsGWP ≥ 150 (200 lb or greater, not the cascade high side); GWP ≥ 300 (less than 200 lb); GWP ≥ 300 (cascade high side)(c)(9)(ii)
Motor vehicle air conditioning (3)
October 24, 2024Motor vehicle air-conditioning in Model Year 2025 and later light-duty passenger cars and trucks (gross vehicle weight rating under 8,500 lb)GWP ≥ 150(a)(13)(i)
Model Year 2028Motor vehicle air-conditioning in medium-duty passenger vehicles, heavy-duty pickup trucks and complete heavy-duty vans whose air-conditioning will not be modified by upfittersGWP ≥ 150(a)(13)(ii)
January 1, 2028Motor vehicle air-conditioning in certain nonroad vehicles (agricultural tractors over 40 horsepower; self-propelled agricultural machinery; compact equipment; construction, forestry and mining equipment; and commercial utility vehicles)GWP ≥ 150(a)(13)(iii)
Foam blowing agents (2)
January 1, 2025Foam products: rigid polyurethane appliance foam, commercial refrigeration foam, laminated boardstock, marine flotation foam, sandwich panels, slabstock; flexible polyurethane; integral skin polyurethane; polystyrene (extruded boardstock, billet, extruded sheet); phenolic insulation board and bunstock; polyisocyanurate laminated boardstock; polyolefin; rigid polyurethane spray foamGWP ≥ 150(a)(14)
January 1, 2026Foam products in the (a)(14) formulations for use in space and military applicationsGWP ≥ 150(a)(15)
Aerosol propellants / solvents (2)
January 1, 2025Aerosol productsGWP ≥ 150(a)(16)(i)
January 1, 2028Aerosol products (all, except defense sprays as defined in 84.3)GWP ≥ 150(a)(16)(ii)

Servicing. 40 CFR 84.54 restricts new manufacture/import, later sale/distribution, and installation. "Installation" is defined in 84.54(e); repairing or servicing existing R-422D equipment is not an installation unless it meets 84.54(e), so existing systems can keep being serviced. From January 1, 2029, servicing or repairing R-422D equipment in supermarket systems, refrigerated transport or automatic commercial ice makers must be done with reclaimed refrigerant[6].

Source: 40 CFR 84.54, current through 91 FR 31329 (May 26, 2026). Installation defined at 40 CFR 84.54(e).

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-422A3.1k

Retrofit and replacement paths

R-422D replaces

Replacements for R-422D

Reading the R-422D PT chart

R-422D's PT chart shows two curves (bubble and dew) — the blend is zeotropic with approximately 7°F glide. Use dew curve at suction pressure for superheat measurement; use bubble curve at discharge pressure for subcooling.

The pressure envelope is close to R-22. Standard 500 PSI manifold gauges handle R-422D — same gauge equipment as R-22 service works for R-422D retrofit.

R-422D vs R-22, R-32, R-454B: saturation pressure

Saturation pressure (PSIG, gauge) for R-422D vs R-22, R-32, R-454B — zeotropic blends shown as dew / bubble. Each column shows the percent difference from R-422D. Source: CoolProp 7.2.0 dataset.
TempR-422DR-22R-32R-454B
0°F21.7 / 28.224.0(−15%)49.3(+74%)42.7 / 45.3(+60%)
40°F66.5 / 76.568.6(−10%)121.0(+58%)107.0 / 112.0(+46%)
70°F120.9 / 133.3121.4(−9%)205.8(+54%)183.1 / 190.5(+43%)
100°F198.8 / 213.2195.9(−8%)325.7(+53%)290.9 / 300.8(+41%)

Frequently asked

›What is R-422D used for?

R-22 retrofit refrigerant for systems where oil change is undesirable. Chemours markets R-422D as Freon MO29 (originally DuPont ISCEON MO29) specifically targeting residential AC, heat pump, and light commercial cooling applications where the existing R-22 mineral oil can be retained[4].

›What's R-422D's GWP?

2729 — substantially higher than R-22 (1,810)[2]. The high GWP is the structural disadvantage of R-422D — it eliminates R-22's chlorine ODP problem but creates a worse GWP problem.

R-422D is no longer specified for new equipment under modern climate policy. Service of existing R-422D retrofits continues; R-32 and R-454B are sub-700 GWP options for full equipment replacement rather than R-422D (GWP 2,729).

›Why does R-422D contain hydrocarbon (R-600a)?

Mineral oil miscibility. HFC refrigerants (R-125, R-134a) are not miscible with mineral oil — without an additive, R-422D would have oil-return problems in R-22 mineral oil systems.

The R-600a fraction is too small (3.4%) to change the blend's A1 safety classification (the non-flammable HFC majority dominates).

›Is R-422D safe to handle?

ASHRAE safety group A1: lower toxicity and no flame propagation[1]. The small R-600a hydrocarbon content does not change the safety class.

›Does R-422D have temperature glide?

Yes, approximately 7°F at typical operating pressures (CoolProp 7.2.0). Use dew curve for superheat measurement (suction line) and bubble curve for subcooling (liquid line). Modern PT calculators handle this automatically when R-422D is selected.

›Should I use R-422D or R-407C for R-22 retrofit?

R-407C has slightly lower GWP (1,774 vs 2,729).

For newer R-22 equipment where the additional work for POE retrofit is justified by the GWP reduction: R-407C.

In 2026, the better answer is often neither — full replacement with R-32 or R-454B equipment (sub-700 GWP) avoids both retrofit blends.

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

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Sources & citations

  1. [1]
    ANSI/ASHRAE Standard 34-2022, Designation and Safety Classification of Refrigerants (free read-only version). ASHRAE. 2022. https://www.ashrae.org/technical-resources/standards-and-guidelines/read-only-versions-of-ashrae-standards (accessed October 2, 2026)
  2. [2]
    40 CFR 84.54 — Restrictions on the use of hydrofluorocarbons. eCFR (Office of the Federal Register). up to date as of 9/29/2026. https://www.ecfr.gov/current/title-40/chapter-I/subchapter-C/part-84/subpart-B/section-84.54 (accessed October 2, 2026)
  3. [3]
    CoolProp 7.2.0. CoolProp (I. H. Bell, J. Wronski, S. Quoilin, V. Lemort). https://coolprop.org/ (accessed October 2, 2026). Bell, I. H.; Wronski, J.; Quoilin, S.; Lemort, V. Pure and Pseudo-pure Fluid Thermophysical Property Evaluation and the Open-Source Thermophysical Property Library CoolProp. Ind. Eng. Chem. Res. 53, 2498–2508 (2014). https://doi.org/10.1021/ie4033999
  4. [4]
    Chemours Freon MO29 (R-422D) Technical Information (formerly DuPont ISCEON MO29). Chemours. https://www.chemours.com/en/brands-and-products/freon-refrigerants (accessed October 2, 2026)
  5. [5]
    2017 Guideline for Assignment of Refrigerant Container Colors (AHRI Guideline N-2017). AHRI. 2017. https://www.ahrinet.org/system/files/2023-06/AHRI_Guideline_N_2017.pdf (accessed October 2, 2026)
  6. [6]
    40 CFR 84.112 — Reclamation. eCFR (Office of the Federal Register). up to date as of 9/25/2026. https://www.ecfr.gov/current/title-40/chapter-I/subchapter-C/part-84/subpart-C/section-84.112 (accessed October 2, 2026). 89 FR 82859, Oct. 11, 2024

Data sources & provenance

PT chart
CoolProp 7.2.0 mixture model: R-125/R-134a/R-600a, 65.1/31.5/3.4% by mass
Properties
CoolProp 7.2.0 + ASHRAE Standard 34-2022
GWP (100-yr)
US EPA value, 40 CFR 84.64(b) · IPCC AR4/AR5/AR6 on the GWP rankings
Table computed
October 2026

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. See how this PT table is calculated in our methodology.