R-134a - 1,1,1,2-Tetrafluoroethane and Replacements to R134a

I can hear the all refrigerator mechanics screaming, but knowledge is power and I hate trades hiding behind “licenses”. So here is some knowledge on how to recharge your A/C system.

Purchasing R134a

R134a is the most common refrigerant in most vehicles on the road, and in Australia it is a licensed gas. This requires a licensed refrigerant tech to re-gas and gas the A/C and you require a purchasing license from the government to got those 5kg gas bottle from A/C supply shops. The governing body in Australia is ARCtick and they control all refrigerant that have global warming protentional (GWP) greater than 100 (nominalized to CO2). However, R134a is in a whole bunch of products that you can buy off the shelf and spray in the air. An example is freezer spray, some brands are 100% R134a, just check the Material Safety Data Sheet (MSDS) if it state 100% R134a it has to be 100% R134a for legal reasons. Then all you need to do is get the R134a into our A/C system, and there are adapters that you can purchase of about $10 that get the push down Schrader valve and have a male 1/4 SAE outlet. So now you can connect the can to your A/C manifold and voilà you have your own source of R134a. If you want to do things by the book there are R134a replacements that do not require a license like the HyChill minus 30. I have used it and it works, you use 70% less compared to R134a and it is cheaper per 100g. I haven’t change the PAG oil in some of my system and they are still working a 1 year later. Your Milage may vary.

How to Charge Your A/C System.

There are heaps of you tube tutorials that will run you through the process to vacuum down an A/C system and charge the system. The important thing to remember when charging your A/C system when you don’t have a scale, is monitor the high pressure side of the system and insure that the pressure that is shown on the gauge is within the range shown in the table below for the correlating ambient temperature. For example, if the outside temperature is 24 degrees Celsius the high side pressure needs to read 10-11 bar. You can over charge an A/C system so use a thermometer in the HVAC vent is the air temperature out of the HVAC vent is not decreasing when refrigerant is added, stop there. Before I charge any of my systems I replace all the Schrader valves in the A/C port and replace the receiver dyer or the desiccant pouch it is cheap insurance, as the PAG oil will become corrosive when it comes in contract when moisture and corrode the aluminum. No one likes replacing evaporator cores.

If you would like a detailed how to guide reach out and if there is a big enough interest I will create a separate how to guide.

Figure 1: Pressure chart of R134a