You may be aware that R134a was commercialized and sold as a replacement for use on R12 type systems. R12 was determined to contribute to depletion of ozone in the earth's upper atmosphere.
As R12 is now being finally phased out, older refrigeration machines need an alternative. Whatever you do, DO NOT USE R-134a in a R12 System! Instead, use a Propane + Isobutane combination, also known as 12a or HC-12a. 12a is also non-ozone depleting, and directly compatible with R-12's compressor oils. Sin.
RS-24 also provides a long term solution to replacing R12 in most applications such as hermetic and semi-hermetic systems, domestic refrigerators, refrigerated transport, cold stores, cellar cooling, dairy chillers, vending machines and including mobile air conditioning.
However, R134a is not a 'drop-in' replacement for R12 because there is a need to change the compressor lubricant and expansion valve. Changing over from R12 to R134a can therefore be an ex-pensive and time consuming procedure.
As previously stated, R12 systems usually use mineral oil, which is incompatible with R134a. When R134a comes into contact with mineral oil, it can hinder the oil from returning to the compressor, or possibly reduce heat transfer.
Limited quantities of reclaimed R-12 is still available for service of installed equipment. A wide variety of R-12 retrofit blends are available.
R12 to R134a Charge Conversion Formula (pounds only)
Take the R12 charge specification and multiply it by 0.9. Then, subtract that result by 0.25 pounds to get the proper amount of R134a charge.
While the production of new R12 is banned, it is not illegal to sell or use R12. In fact, many of the cylinders and cans of Freon R12 sold for decades throughout the United States are still around today.
In most cases, mixing different types of refrigerants is illegal. Mechanically, adding R-12a to an R-134a system won't harm anything. R-12a is a hydrocarbon-based refrigerant. It's mostly propane & butane, so highly flammable.
The AIM Act is a Federal nationwide rule phasing out the use of global warming materials. As part of that effort, EPA is now banning the use of 134a in aerosol products as of 1/1/2025. There are excepted products that are allowed to use 134a until 1/1/2028.
Dichlorodifluoromethane (R-12) is a colorless gas popularly known by the genericized brand name Freon (as Freon-12). It is a chlorofluorocarbon halomethane (CFC) used as a refrigerant and aerosol spray propellant.
Propane makes a good substitute for R12 with very little modifications.
Just buy some r12 on ebay if you aren't wanting newer refrigerant. As Rich said positively DO NOT use R22. R22 is quite valuable right now so that 20lb is worth some jingle. R-22 and R-12 are not interchangeable .
RS-24 is a “Drop-in” alternative for R12 which also provides a long term solution at the same time. It provides, therefore, a one change solution to the replacement of R12 at minimal expense.
R600a is a good replacement for R12
However its smaller volumetric capacity and higher pressure ratios, limit it to very small capacities. With regard to R600a, it has a lower molecular weight, 58.1 kg/kmol in comparison to R134a, 102 kg/kmol, which results in a lower charge for Isobutane.
Automotive service technicians depend on Freon™ 134a (R-134a) refrigerant, a non-ozone depleting hydrofluorocarbon (HFC) replacement for R-12. Freon™ 134a is the standard in many mobile air conditioning (AC) units, and also replaces R-12 in: Commercial stationary refrigeration systems.
No retrofitting needed. RED TEK 12a is designed as a direct drop-in replacement for R-134a and R-12 substitutes.
An HCFC Replacement Refrigerant for R-12
Freon™ 409A carries an ASHRAE A1 safety classification and blends R-22, R-142b, and R-124. It can be used in medium- and low-temperature positive displacement equipment.
You can use your normal equipment; Minus 30 is suitable for all systems. It doesn't matter whether it is an old R12 system, or a new R134a system, Minus 30 is compatible with all oils, O Rings, Seals and Gaskets.
While it can no longer be manufactured, there is a surprising amount of Freon still available as new old stock (NOS).
EMERGENCY OVERVIEW: Colorless, volatile liquid with ethereal and faint sweetish odor. Non-flammable material. Overexposure may cause dizziness and loss of concentration. At higher levels, CNS depression and cardiac arrhythmia may result from exposure.
You can usually find cans on Ebay. However, to handle it legally (in the US) you need an EPA 609 certification, which you can get at EPATest.com for $20. R12 manufacture was banned in the US in 1994, as it's not very planet-friendly, so it's getting more expensive.
Or, if you'd like to tackle the job yourself, AutoZone has all the tools and refrigerant to service your R-134A or R-12 vehicle.
A very frequent question people ask us is whether it is legal to sell R12 refrigerant. The answer is yes – but not to just anybody. It is only possible to sell Freon, R-12 or any other CFC to EPA-certified technicians, like the experts at Refrigerant Finders.
Weighing in at a 14.7 grams per can, you will need 32 cans per pound. That is a source quote.