R-409A PT Chart and Refrigerant Profile

Where you will find R-409A

R-409A is an all-HCFC service blend built to keep R-12 refrigeration running after CFC production ended. It combines R-22, R-124 and R-142b. You will find it in converted commercial refrigeration (reach-ins, walk-ins, display cases) and in domestic refrigerators and freezers. EPA’s SNAP program listed it for R-12 systems in household refrigerators and freezers on Aug 26 1994.

Look for a retrofit tag on a system whose compressor and nameplate still say R-12. The legacy R-409A cylinder color was tan. Cylinders made since 2020 are light green-gray for every refrigerant, so go by the label. A system without a tag whose pressures do not track R-12 should be identified before you add anything. R-409A and R-401A were sold for the same job and are easy to confuse, but their PT tables differ.

Charging R-409A

R-409A is a zeotropic blend, and its glide is wider than that of R-401A. The computed glide at 40°F evaporating is 14.3°F, and it shifts with pressure. That has two consequences at the unit.

Charge liquid only. If you draw vapor from the cylinder, the lighter components leave first. The system gets the wrong mix and the cylinder left behind drifts too. Meter liquid in slowly so it flashes before the compressor.

Read the right column. Superheat is measured from the dew (vapor) column at suction pressure. Subcooling is measured from the bubble (liquid) column at liquid-line pressure. With 14°F of glide, using the wrong column throws the reading off badly. The superheat calculator picks the dew column for you; use the bubble column for subcooling. The temperature glide calculator shows the gap at any pressure.

Charge to the equipment maker’s or the retrofit procedure’s instructions; on a TXV system, charge by subcooling to that target.

Expect gauges that look different from R-12. On this site’s tables, R-409A reads 34.0 psig at a 40°F dew point; R-12 reads 36.9 psig at 40°F. On the high side, a 100°F bubble point is 146.8 psig for R-409A against 116.9 psig for R-12. Do not charge an R-409A system to R-12 pressures.

Oil and compatibility

BITZER lists mineral oil and alkylbenzene for R-409A, the same oil family as R-12. Use the lubricant the compressor manufacturer approves.

Do not mix R-409A with R-12, R-401A, R-134a or anything else in the same system. A mixture matches no PT chart, so the charge can no longer be checked.

Moving off R-409A to an HFC means an oil change. R-134a mixes poorly with mineral oil and AB. Chemours’ R-513A retrofit guidelines call for changing to POE when converting from HCFC service blends that ran mineral oil or AB. See the refrigerant oil types guide.

Safety, handling and recovery

R-409A is ASHRAE class A1: lower toxicity, no flame propagation. It is an ozone-depleting refrigerant, with an ODP of 0.048 computed from the 40 CFR 82 values for its three HCFCs. Knowingly venting it is prohibited, recovery is required, and sales are limited to certified technicians.

40 CFR 82.152 classes refrigerants by liquid saturation pressure at 104°F: 45 to 170 psia is medium-pressure, 170 to 355 psia high-pressure. R-409A sits on that line: this site’s chart gives 156.0 psig (170.7 psia) at 104°F, within the model’s accuracy of the boundary. Recover it to the medium-pressure levels below; they are deeper vacuums than the high-pressure ones (0 in Hg under 200 lb), so they satisfy either reading. Factory-sealed appliances of 5 lb or less need Type I certification, other equipment Type II, and Universal covers both.

Appliances with 50 lb or more are subject to the ODS leak-repair rules in 40 CFR 82.157. Recovered R-409A cannot be sold to a new owner unless an EPA-certified reclaimer has reclaimed it (40 CFR 82.154(d)).

Status and replacements

Every component of R-409A is a Class II HCFC. HCFC-22 and HCFC-142b production and import allowances went to zero in 2020. HCFC-124 allowances decline to zero in 2030 (40 CFR 82.16). Since Jan 1 2020, newly produced HCFC-124 may be used only to service equipment manufactured before that date (40 CFR 82.15).

EPA has not published a statement on R-409A as a blend. Read together, those rules mean virgin R-409A is limited and what remains in the field is recovered, reclaimed or older stock. It contains no HFC, so the AIM Act phasedown and the Part 84 leak-repair and reclaim rules do not apply to it.

When a system on R-409A needs major work, the sourced conversion paths are:

• R-134a with an oil change. See R-12 vs R-134a for the pressure differences against the original R-12 design.
• R-513A with an oil change to POE, per Chemours’ retrofit guidelines.

Compare them in the R-134a replacement guide, and confirm compressor approval before choosing.

Common questions

What oil does R-409A use?

Mineral oil or alkylbenzene, per BITZER. R-12 systems ran mineral oil, so a retrofit from R-12 usually starts from compatible oil; follow the compressor maker. A conversion to R-134a or R-513A requires POE (or PAG in vehicles for R-134a).

Can R-409A replace R-12?

It was designed as an R-12 service blend and EPA listed it for R-12 household refrigerators and freezers in 1994. It runs higher head pressure and has a wide glide, so charge it as liquid and read the dew and bubble columns, not an R-12 chart.