R-502 Refrigerant PT Chart

One of the very first steps when it comes to diagnosing your home air conditioner, refrigerator, or even your vehicle’s air conditioner is understanding the temperature and the current pressure that your system is operating at. Having these facts along with the saturation point, the subcool, and the  superheat numbers for the refrigerant you are working on are essential when it comes to really understanding what is going wrong with your system.

After a visual inspection the very next step for the most seasoned technicians is pulling out their gauges and checking the pressure and temperature. It just becomes second nature after enough calls. I have heard stories of rookie techs calling some of the pros on their team for help on a system that they’re stuck on. It doesn’t matter what the situation is. It doesn’t matter if you’re in Miami or in Fargo. It will never fail that one of the first questions the pros ask the rookie is what is your subcool and what is your superheat? Having  and understanding these numbers is key to figuring out what to do next.

But, these numbers won’t do you any good if you don’t know what refrigerant you are dealing with and what the refrigerant’s boiling point is at each pressure level. This article aims at providing you with just that information.

R-502 Refrigerant Information

R-502 is one of those refrigerants you just do not see around much anymore. R-502 is a CFC refrigerant just like it’s cousin refrigerant R-12 and R-11. All of these refrigerants were found to be damaging the Ozone layer when they were released into the atmosphere. Because of this, these refrigerants were phased out across the world through a global treaty known as the Montreal Protocol. R-12 was one of the first ones to go but R-502 wasn’t far behind. It’s complete phase out occurred in 1995.

Originally, R-502 was designed to operate in a low temperature refrigerant applications. It was meant as an alternative to the very popular HCFC known as R-22. R-502 had an overall lower discharge temperature and an improved capacity allowance when compared to R-22. This made it a great alternative… until the phase outs began. Nowadays it is a rare feat to find a functioning R-502 system. Most of these have been retired due to old age or they have been retrofitted to accept a new refrigerant. The most common replacement refrigerant was the HFC R-404A, but now even 404A is being phased out due to it’s high Global Warming Potential.

In the off chance that you do come across a R-502 application then you will need to know the pressures. Let’s take a look at our pressure chart below.

R-502 PT Chart