R-452B PT Chart and Refrigerant Profile

Where you will find R-452B

R-452B is an A2L blend for new positive-displacement air conditioning, heat pumps and chillers, in place of R-410A. Chemours sells it as Opteon XL55 and lists window units, portables, mini-splits, ducted splits, PTACs, commercial packaged units, multi-splits and DX chillers (Opteon XL55 product information). Honeywell sold it as Solstice L41y for DX chillers, high-pressure heat pumps, split AC, rooftop units and VRF.

The other A2L options in the same equipment are R-454B and R-32. Identify it by the nameplate and the A2L labels. EPA’s use conditions require red (PMS #185 or RAL 3020) hoses and piping, marked service ports and warning labels on equipment built for it.

The cylinder is the standard light green-gray (RAL 7044) with a red band on the shoulder or top for a flammable refrigerant. Guideline N-2017 Table 1 assigns R-452B no legacy color.

Charging R-452B

Charge as liquid. R-452B is a zeotropic blend of R-32, R-125 and R-1234yf, and vapor drawn off the cylinder does not match the 67/7/26 mix. We found no Chemours or Honeywell charging procedure, so the equipment installation manual is the only charging authority.

The glide is small: about 2.2°F at a 40°F dew point. At 40°F this chart gives 109.4 psig dew and 114.2 psig bubble, against 118.4 psig for R-410A. Read the right column:

• Superheat: suction pressure against the dew column. On a fixed metering device, charge to target superheat (CEC Title 24 Table RA3.2-2, installer tolerance ±5°F, valid at 55–115°F outdoor dry bulb, return dry bulb 70°F or higher and return wet bulb 76°F or lower). Use the target superheat calculator.
• Subcooling: liquid-line pressure against the bubble column. TXV and EEV systems are charged to the nameplate or manual subcooling target, ±3°F for the installer under Title 24. Use the subcooling calculator.

R-452B and R-454B are close but not the same, so never read one chart for the other. The temperature glide calculator shows the gap at any pressure. Line-set adders vary by manufacturer; take them from the unit’s manual.

Oil and compatibility

Equipment for R-452B ships with POE. BITZER lists POE and PVE, and the Honeywell L41y brochure recommends POE and says to check with the compressor maker. Danfoss factory-charges POE in its R-452B scrolls: 160SZ in DSH models and 215PZ or 160SZ in VZH variable-speed models, depending on size (Danfoss oil overview). Add only the oil named on the compressor, and see the refrigerant oil guide.

Chemours says Opteon XL55 is intended for new equipment design only. Do not put it in an R-410A system or top off R-410A with it.

Safety, handling and recovery

A2L means lower toxicity and mild flammability, with a burning velocity of 10 cm/s or less (flammability classes explained). EPA’s residential AC listing requires equipment that meets UL 60335-2-40, 3rd edition. Keep ignition sources away from the work area and follow the A2L service steps in the manual (A2L installation and service).

Recover with a machine certified for flammable refrigerants under 40 CFR 82.158 Appendix B4, which adds UL 1963 Supplement SB to AHRI 740 (recovery machine compatibility). Many A2L cylinders use left-hand thread valves; that is industry practice, not a Guideline N provision, so carry the adapter.

Section 608 Type II or Universal certification covers it, and Type I covers factory-sealed units of 5 lb or less. Its computed liquid saturation pressure at 104°F is 338.6 psia (323.9 psig, bubble), which makes it a high-pressure refrigerant under 40 CFR 82.152, though close to the 355 psia line. Recover appliances under 200 lb to 0 in Hg, and 200 lb or more to 10 in Hg.

Status and replacements

The GWP is the story. EPA’s 40 CFR 84.64 method gives 697.5, just under the 700 limit in 40 CFR 84.54 for new residential and light commercial AC and heat pumps (from Jan 1 2025), VRF (from Jan 1 2026), comfort chillers and data-center cooling. The common AR4 convention prints 698; AR5 gives 676. It is above the 150 and 300 limits used for refrigeration sectors.

EPA SNAP listings, all for new equipment:

• residential and light commercial AC and heat pumps, acceptable subject to use conditions (86 FR 24444, May 6 2021)
• centrifugal and positive-displacement comfort chillers, industrial process AC and residential dehumidifiers (88 FR 26382, Apr 28 2023)

R-452B is not on EPA’s pages for retail food, cold storage, transport or ice rinks. Its R-32 and R-125 count against the AIM Act phasedown (60% of baseline in 2024–2028, 30% in 2029–2033); R-1234yf is not a regulated substance under Part 84.

No source names a successor. For how it fits next to the other R-410A alternatives, see R-410A replacement options, R-410A vs R-454B and the A2L refrigerants guide.

Common questions

Is Opteon XL55 the same as R-452B?

Yes. Opteon XL55 is Chemours’ name for R-452B, and Solstice L41y is the Honeywell name for the same blend.

Can R-452B replace R-410A in an existing system?

No. EPA lists it for new equipment only, Chemours says XL55 is for new equipment design, and the system needs A2L-rated components and mitigation. See R-410A replacement options.