R-454C PT Chart and Refrigerant Profile

Where you will find R-454C

R-454C is an A2L blend of R-32 and R-1234yf, sold as Chemours Opteon XL20 and Solstice 454C. Solstice and Chemours list it for new low- and medium-temperature commercial refrigeration: condensing units, plug-in and self-contained cases, cold storage and transport refrigeration, and also heat pumps (Solstice). Chemours positions it as a new-equipment alternative to R-404A, R-507A, R-448A, R-22 and R-407A (replacement guide).

Identify it from the unit nameplate and cylinder label. It shares its components with R-454A and R-454B, but at 21.5/78.5 it has the least R-32 and the lowest pressures of the three: at a 40°F dew point the computed charts give 59.6 psig for R-454C, 74.3 for R-454A and 107.5 for R-454B. A chart for the wrong blend will be badly off.

Charging R-454C

R-454C has a large glide: about 14.9°F at 40°F evaporating and 13.3°F at 100°F condensing in the computed data. Charge it as liquid from the cylinder; vapor drawn off a zeotropic blend has a different composition from the liquid.

At 40°F the computed bubble pressure is 81.4 psig and the dew pressure 59.6 psig, nearly 22 psi apart. Use the dew column with suction pressure for superheat and the bubble column with liquid-line pressure for subcooling. With glide this large, the glide calculator and the PT chart guide are worth a look before your first R-454C job.

The computed chart has a known offset. CoolProp’s fitted R-32/R-1234yf model puts the dew line 0.9 to 5.5 psi (2.5–2.7%) below both the Chemours and the Honeywell tables, which agree with each other; the bubble line is within 1% below 40°F and 2.9 psi (1.2%) low at 100°F. The validation section below lists the points. For close superheat readings, cross-check the suction saturation against the Chemours XL20 or Solstice 454C PT data.

Charge to the equipment manufacturer’s instructions. On TXV and EEV systems check the subcooling target with the subcooling calculator; self-contained units are charged by weight to the nameplate. The target superheat calculator applies to fixed-metering comfort air conditioners only.

Oil and compatibility

Solstice lists POE or PVE for R-454C; Chemours lists POE. The compressor label decides which.

R-454C is listed for new equipment. Converting an existing A1 system to an A2L refrigerant is not a lubricant question alone: the equipment would need a flammable-refrigerant listing and to meet EPA’s SNAP use conditions. See the oil types guide.

Safety, handling and recovery

R-454C is class A2L: lower toxicity and mildly flammable, with a burning velocity of 10 cm/s or less (flammability classes). EPA lists it as acceptable subject to use conditions in residential and light commercial AC and heat pumps (86 FR 24444, 2021) and in commercial and industrial refrigeration including cold storage (89 FR 50410, June 13, 2024). The use conditions include red (PMS #185) flammable-refrigerant markings. It is not exempt from the venting prohibition.

Under Section 608 it is a high-pressure appliance refrigerant (40 CFR 82.152), so Type II or Universal certification is required. Recover to 0 in Hg on systems under 200 lb and 10 in Hg on 200 lb or more (40 CFR 82.156). The recovery machine must be certified under Appendix B4 of 40 CFR 82.158 (UL 1963 Supplement SB for flammable refrigerants); see recovery machine compatibility. Equipment makers require A2L-rated service equipment on A2L systems, so follow the manual for gauges, vacuum pumps and leak detectors, and see refrigerant detection systems for sensor requirements.

The 40 CFR 84.106 leak repair rules apply from January 1, 2026 to appliances with 15 lb or more of a substitute with GWP above 53; at 148, R-454C is covered.

New containers are light green-gray (RAL 7044) with a red band on the shoulder or top for flammable refrigerants (AHRI Guideline N-2017). No legacy color for R-454C was verified. Many A2L cylinders use left-hand thread valves as an industry practice, so check the valve before connecting an adapter. See cylinder colors.

Status and replacements

R-454C’s GWP is 148 on the AR4 basis and 145.9 in EPA’s 40 CFR 84.64 calculation, below every Technology Transitions limit in its sectors. The May 2026 final rule (91 FR 31284) set interim limits of 1,400 for new remote condensing units (from July 27, 2026) and supermarket systems (from January 1, 2027) and 700 for new cold storage (from July 27, 2026). From January 1, 2032, 40 CFR 84.54 lowers those to 300 for systems under 200 lb and cascade high sides and 150 for systems of 200 lb or more. R-454C is under 150, so it meets both.

Its R-32 content is still an HFC under the AIM Act phasedown; R-1234yf is an HFO and not a regulated substance under Part 84. From January 1, 2029, servicing supermarket systems, refrigerated transport and automatic commercial ice makers must use reclaimed refrigerant (40 CFR 84.112(e)).

R-454C is itself a replacement, so there is no successor yet. The nearest alternative is R-455A, with the same R-32 share plus 3% CO2. See the R-404A replacement comparison.

Common questions

What is the difference between R-454C and R-454B?

Both are A2L R-32/R-1234yf blends. R-454B is 68.9/31.1 with GWP 466 and is the residential AC refrigerant; R-454C is 21.5/78.5 with GWP 148, much lower pressures and more glide, aimed at refrigeration. They are not interchangeable.

What is the difference between R-454C and R-455A?

R-455A uses the same 21.5% R-32 but replaces some R-1234yf with 3% CO2. Both have GWP 148 on the AR4 basis. R-455A has more glide (about 23.0°F at 40°F evaporating, computed, against 14.9°F) and higher bubble pressures.