R-434A (RS-45) PT Chart and Refrigerant Profile

Where you will find R-434A

R-434A is RS-45, an R-22 retrofit blend from Refrigerant Solutions Ltd that A-Gas sells in Canada and South Africa and Gas Servei sells in Spain. In the US, a 2026 ChemPoint page lists ComStar RS-45 as a current product, described as a drop-in replacement for R-22 with no oil, system or component change required.

A-Gas Canada lists commercial AC, transport refrigeration, food retail, dairy chillers, cellar cooling and water chillers. It calls RS-45 the only R-22 replacement suitable for flooded evaporators; that is the supplier’s claim, not an independent test. Gas Servei positions it for large AC and general refrigeration with TXVs, evaporating down to -35°C (-31°F).

Look for it in converted R-22 chillers, condensing units and refrigeration systems. The nameplate keeps the R-22 rating, so the retrofit label is the identifier. The legacy label color is sulfur yellow (PMS 388) under AHRI Guideline N-2017.

Unlike most R-22 drop-ins, it contains R-143a, one of the two main components of R-404A. Its pressures run above R-22.

Charging R-434A

Accuracy note: this site’s computed R-434A chart reads 1.2 to 7.8 psi (about 2.6–3.3%) above the only published reference we found, the RSL RS-45 table, with the largest gaps at condensing temperatures. When you set a charge, use the RSL or supplier chart or the equipment charging chart, not the computed values on this page.

Always charge liquid. A-Gas South Africa says it must be charged from the liquid phase, and Gas Servei says to always load it as liquid. It is a zeotrope with a few degrees of glide, so read the dew column for superheat and the bubble column for subcooling, using the supplier’s chart.

On fixed metering devices, set the charge by target superheat. On TXV and EEV systems, use the manufacturer’s subcooling target. Gas Servei notes the expansion valve may need to be opened or adjusted after conversion. We found no RS-45 charge-weight guidance, so follow the equipment manufacturer and add liquid in small steps toward the system’s targets.

Gas Servei says a system can be refilled after a leak. Repair the leak first.

Oil and compatibility

Suppliers differ on oil:

• A-Gas Canada: works with mineral oil, AB and POE; no oil change is needed going from R-22, but follow the compressor maker.
• A-Gas South Africa: works with most current oils, POE preferred.
• Gas Servei: compatible with the original system oil.
• BITZER: POE only.

If the compressor is a BITZER, or the manufacturer’s approval list calls for POE, change the oil. Replace the filter-drier when the system is open and evacuate to the OEM target (evacuation guide). More in the refrigerant oil guide.

Safety, handling and recovery

R-434A is A1 (lower toxicity, no flame propagation) per BITZER, A-Gas and EPA, despite the 2.8% isobutane.

It is a Section 608 high-pressure refrigerant. Its liquid saturation pressure at 104°F sits well inside the 170–355 psia band, even allowing for the chart difference above. Type II or Universal certification covers it, and sales have been limited to certified technicians since Jan 1 2018. Recover appliances made after Nov 15 1993 to 0 in Hg under 200 lb of charge and 10 in Hg at 200 lb or more (refrigerant recovery).

New cylinders since Jan 1 2020 are light green-gray (RAL 7044); sulfur yellow appears on the label only (cylinder colors).

Status and replacements

EPA SNAP has listed R-434A as acceptable, retrofit and new, since Oct 4 2007 in residential and light commercial AC, industrial process AC and refrigeration, refrigerated transport, water coolers, ice machines, ice rinks and dehumidifiers. The supermarket systems and remote condensing unit pages show it as unacceptable for retrofit from July 20 2016. Court decisions (Mexichem Fluor v. EPA, 2017 and 2019) partly vacated those 2015 listings, but EPA’s pages still print them, so check the current rule before converting a rack.

Its AR4 GWP of about 3,245 is above every Technology Transitions limit for new equipment. 40 CFR 84.54 also names it for new road and marine refrigerated transport (Jan 1 2025), several ice machine and food processing categories (Jan 1 2027) and UL 621 ice cream makers (Jan 1 2028). Servicing existing systems remains legal, and the leak repair rule applies to appliances with 15 lb or more of HFC from Jan 1 2026.

No source names a successor. Compare lower-GWP routes off R-22 in R-22 replacement options, and see the GWP chart for how it ranks.

Common questions

What is R-434A used for?

It is an R-22 retrofit for existing AC, chillers and refrigeration. A-Gas lists low-, medium- and high-temperature uses, including flooded evaporators.

What is the GWP of R-434A?

About 3,245 on the AR4 basis that EPA uses (3,245.4 by EPA’s 40 CFR 84.64 method), against an AR4 value of 1,810 for R-22.