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-407C Refrigerant Information
R-407C is one of the many replacement products for the now phased out R-22. R-22’s official phase down started in 2010 and the final phase out began on January 1st, 2020. Over that ten year period there were hundreds, and I really mean hundreds, of R-22 alternatives created. One of these replacement products was the hydroflurocarbon blend known as R-407C.
R-407C is a zeotropic blend of R-32 (Difluromethane), R-125, and R-134a (Tetrafluoroethane). It is not a drop in replacement on R-22 machines. If you wish to use this product you will need to vacate all of the old R-22 out of the system. This is due to the R-22 systems using mineral oil and this HFC blend using POE oil. You will also need to replace the compressor as well. If this is not done then you risk destroying your air conditioner.
It is difficult to say exactly how long R-407C will be around. With each year that passes the R-22 machines grow older and older. By the year 2030 there will be very few of them left. Before then though, R-407C will still be needed.
Let’s take a look at our pressure chart.
R-407C PT Chart
| Temp (F) | Temp (C) | Liquid Pressure (PSIG) | Vapor Pressure (PSIG) |
|---|---|---|---|
| -94 | -70 | -11.28 | -12.63 |
| -90.4 | -68 | -10.82 | -12.32 |
| -86.8 | -66 | -10.31 | -11.97 |
| -83.2 | -64 | -9.75 | -11.59 |
| -79.6 | -62 | -9.14 | -11.15 |
| -76 | -60 | -8.46 | -10.67 |
| -72.4 | -58 | -7.71 | -10.14 |
| -68.8 | -56 | -6.9 | -9.55 |
| -65.2 | -54 | -6.01 | -8.9 |
| -61.6 | -52 | -5.04 | -8.19 |
| -58 | -50 | -3.98 | -7.41 |
| -54.4 | -48 | -2.84 | -6.55 |
| -50.8 | -46 | -1.6 | -5.61 |
| -47.2 | -44 | -0.26 | -4.59 |
| -43.6 | -42 | 1.19 | -3.48 |
| -40 | -40 | 2.75 | -2.27 |
| -36.4 | -38 | 4.43 | -0.96 |
| -32.8 | -36 | 6.23 | 0.46 |
| -29.2 | -34 | 8.16 | 1.99 |
| -25.6 | -32 | 10.23 | 3.64 |
| -22 | -30 | 12.45 | 5.42 |
| -18.4 | -28 | 14.81 | 7.33 |
| -14.8 | -26 | 17.33 | 9.38 |
| -11.2 | -24 | 20.01 | 11.58 |
| -7.6 | -22 | 22.87 | 13.93 |
| -4 | -20 | 25.9 | 16.44 |
| -0.4 | -18 | 29.12 | 19.12 |
| 3.2 | -16 | 32.53 | 21.98 |
| 6.8 | -14 | 36.14 | 25.02 |
| 10.4 | -12 | 39.96 | 28.25 |
| 14 | -10 | 43.99 | 31.68 |
| 17.6 | -8 | 48.25 | 35.32 |
| 21.2 | -6 | 52.73 | 39.17 |
| 24.8 | -4 | 57.46 | 43.25 |
| 28.4 | -2 | 62.43 | 47.56 |
| 32 | 0 | 67.65 | 52.11 |
| 35.6 | 2 | 73.14 | 56.92 |
| 39.2 | 4 | 78.9 | 61.98 |
| 42.8 | 6 | 84.94 | 67.31 |
| 46.4 | 8 | 91.27 | 72.92 |
| 50 | 10 | 97.89 | 78.82 |
| 53.6 | 12 | 104.82 | 85.01 |
| 57.2 | 14 | 112.06 | 91.51 |
| 60.8 | 16 | 119.63 | 98.33 |
| 64.4 | 18 | 127.53 | 105.48 |
| 68 | 20 | 135.76 | 112.96 |
| 71.6 | 22 | 144.35 | 120.79 |
| 75.2 | 24 | 153.29 | 128.98 |
| 78.8 | 26 | 162.62 | 137.55 |
| 82.4 | 28 | 172.3 | 146.48 |
| 86 | 30 | 182.38 | 155.82 |
| 89.6 | 32 | 192.86 | 165.56 |
| 93.2 | 34 | 203.74 | 175.71 |
| 96.8 | 36 | 215.04 | 186.3 |
| 100.4 | 38 | 226.77 | 197.32 |
| 104 | 40 | 238.92 | 208.8 |
| 107.6 | 42 | 251.53 | 220.75 |
| 111.2 | 44 | 264.6 | 233.19 |
| 114.8 | 46 | 278.12 | 246.12 |
| 118.4 | 48 | 292.13 | 259.56 |
| 122 | 50 | 306.63 | 273.54 |
| 125.6 | 52 | 321.62 | 288.06 |
| 129.2 | 54 | 337.14 | 303.14 |
| 132.8 | 56 | 353.18 | 318.81 |
| 136.4 | 58 | 369.74 | 335.08 |
| 140 | 60 | 386.85 | 351.97 |
| 143.6 | 62 | 404.52 | 369.52 |
| 147.2 | 64 | 422.78 | 387.73 |
| 150.8 | 66 | 441.6 | 406.65 |
| 154.4 | 68 | 461.03 | 426.31 |
| 158 | 70 | 481.05 | 446.75 |