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-404A History
R-404A rose to prominence in the late 1990’s with the phasing out of CFC and HCFC refrigerants like R-12 and R-502. There had to be a replacement for the Ozone damaging refrigerants of the past and the successor was the HFC R-404A that we all know of today.
404A’s reign however was short lived. R-404A has one of the highest Global Warming Potential numbers of any modern day refrigerant and is known as a super pollutant. Because of this we are seeing various countries and manufacturers no longer using R-404A in new machinery. Instead, companies and countries are opting for more climate friendly refrigerants such as natural refrigerants, hydrocarbons, and newer less GWP heavy HFO refrigerants
If you would like to read more about R-404A refrigerant please check our refrigerant R-404A fact sheet.
R-404A PT Chart
Let’s take a look at our pressure table for R-404.
| °F | °C | PSI | KPA |
| -40 | -40.0 | 4.3 | 29.6 |
| -35 | -37.2 | 6.8 | 46.9 |
| -30 | -34.4 | 9.5 | 65.5 |
| -25 | -31.7 | 12.5 | 86.2 |
| -20 | -28.9 | 15.7 | 108.2 |
| -15 | -26.1 | 19.3 | 133.1 |
| -10 | -23.3 | 23.2 | 160.0 |
| -5 | -20.6 | 27.5 | 189.6 |
| 0 | -17.8 | 32.1 | 221.3 |
| 5 | -15.0 | 37 | 255.1 |
| 10 | -12.2 | 42.4 | 292.3 |
| 15 | -9.4 | 48.2 | 332.3 |
| 20 | -6.7 | 54.5 | 375.8 |
| 25 | -3.9 | 61.2 | 422.0 |
| 30 | -1.1 | 68.4 | 471.6 |
| 35 | 1.7 | 76.1 | 524.7 |
| 40 | 4.4 | 84.4 | 581.9 |
| 45 | 7.2 | 93.2 | 642.6 |
| 50 | 10.0 | 103 | 710.2 |
| 55 | 12.8 | 113 | 779.1 |
| 60 | 15.6 | 123 | 848.1 |
| 65 | 18.3 | 135 | 930.8 |
| 70 | 21.1 | 147 | 1013.5 |
| 75 | 23.9 | 159 | 1096.3 |
| 80 | 26.7 | 173 | 1192.8 |
| 85 | 29.4 | 187 | 1289.3 |
| 90 | 32.2 | 202 | 1392.7 |
| 95 | 35.0 | 218 | 1503.1 |
| 100 | 37.8 | 234 | 1613.4 |
| 105 | 40.6 | 252 | 1737.5 |
| 110 | 43.3 | 270 | 1861.6 |
| 115 | 46.1 | 289 | 1992.6 |
| 120 | 48.9 | 310 | 2137.4 |
| 125 | 51.7 | 331 | 2282.2 |
| 130 | 54.4 | 353 | 2433.9 |
| 135 | 57.2 | 377 | 2599.3 |
| 140 | 60.0 | 401 | 2764.8 |
Conclusion
There you have it folks. I hope this article was helpful and if you find that something is inaccurate here in my chart please do not hesitate to reach out to me. I have sourced this the best I could but there is always going to be conflicting data. I’ve seen it multiple times on various refrigerants. I’ll search for a refrigerant’s pressure chart and get various results all showing different pounds per square inch temperatures.
The aim with this article is to give you accurate information so again, if you see anything incorrect please let us know by contacting us. On top of this post we are also working on a comprehensive refrigerant pressure/temperature listing. The goal is to have every refrigerant out there listed with a pressure/temperature chart that is easily available.