R-134a is the most common refrigerant found in automobiles today. It has been in use since the early 1990’s and now, in 2019, we are beginning to see it’s popularity wane with the rise of the new HFO refrigerant known as R-1234yf. That being said, there are still millions of cars on the road that use R-134a and there will be continue to be for at least another decade or more.
When something does go wrong with your car’s air conditioner a lot of folks are not sure what to do or where to even start. One of the very first steps is to check the pressure of your system. Understanding the pressure that your system is at as well as knowing what the saturation point is of R-134a will allow you to properly diagnose what is wrong with your system. Remember, that air conditioning is basically changing the pressure on the refrigerant until a state change is reached. If your pressure is off then that could point you in the right direction.
With the facts behind you can then begin to determine if your compressor is at fault, perhaps your condenser, or it could be something as simple as your blower motor needing replaced. Without knowing the pressure in your system and the corresponding saturation point then you are in essence going in blind when you attempt to troubleshoot your air conditioning system. I can assure you that when you take your vehicle into a dealership that the pressure and temperature are one of the first things they check when troubleshooting.
For more information on R-134a we also have our official ‘R-134a Refrigerant Fact and Information Sheet.’ This fact sheet goes into anything and everything you’d ever want to know about R-134a. There’s quite a bit to read, but if it is definitely worth your while if you’re interesting learning more about this HFC refrigerant. We also have an interesting article that goes into the history of R-134a.
R-134a PT chart
| °F | °C | PSI | KPA |
|---|---|---|---|
| -49 | -45 | 18.4 | 126.9 |
| -48 | -44.4 | 18 | 124.1 |
| -47 | -43.9 | 17.6 | 121.3 |
| -46 | -43.3 | 17.3 | 119.3 |
| -45 | -42.8 | 16.9 | 116.5 |
| -44 | -42.2 | 16.5 | 113.8 |
| -43 | -41.7 | 16.1 | 111 |
| -42 | -41.1 | 15.7 | 108.2 |
| -41 | -40.6 | 15.2 | 104.8 |
| -40 | -40 | 14.8 | 102 |
| -39 | -39.4 | 14.4 | 99.3 |
| -38 | -38.9 | 13.9 | 95.8 |
| -37 | -38.3 | 13.4 | 92.4 |
| -36 | -37.8 | 13 | 89.6 |
| -35 | -37.2 | 12.5 | 86.2 |
| -34 | -36.7 | 12 | 82.7 |
| -33 | -36.1 | 11.4 | 78.6 |
| -32 | -35.6 | 10.9 | 75.2 |
| -31 | -35 | 10.4 | 71.7 |
| -30 | -34.4 | 9.8 | 67.6 |
| -29 | -33.9 | 9.3 | 64.1 |
| -28 | -33.3 | 8.7 | 60 |
| -27 | -32.8 | 8.1 | 55.8 |
| -26 | -32.2 | 7.5 | 51.7 |
| -25 | -31.7 | 6.9 | 47.6 |
| -24 | -31.1 | 6.3 | 43.4 |
| -23 | -30.6 | 5.7 | 39.3 |
| -22 | -30 | 5 | 34.5 |
| -21 | -29.4 | 4.3 | 29.6 |
| -20 | -28.9 | 3.7 | 25.5 |
| -19 | -28.3 | 3 | 20.7 |
| -18 | -27.8 | 2.3 | 15.9 |
| -17 | -27.2 | 1.5 | 10.3 |
| -16 | -26.7 | 0.8 | 5.5 |
| -15 | -26.1 | 0.1 | 0.7 |
| -14 | -25.6 | 0.4 | 2.8 |
| -13 | -25 | 0.7 | 4.8 |
| -12 | -24.4 | 1.1 | 7.6 |
| -11 | -23.9 | 1.5 | 10.3 |
| -10 | -23.3 | 1.9 | 13.1 |
| -9 | -22.8 | 2.4 | 16.5 |
| -8 | -22.2 | 2.8 | 19.3 |
| -7 | -21.7 | 3.2 | 22.1 |
| -6 | -21.1 | 3.6 | 24.8 |
| -5 | -20.6 | 4.1 | 28.3 |
| -4 | -20 | 4.6 | 31.7 |
| -3 | -19.4 | 5 | 34.5 |
| -2 | -18.9 | 5.5 | 37.9 |
| -1 | -18.3 | 6 | 41.4 |
| 0 | -17.8 | 6.5 | 44.8 |
| 1 | -17.2 | 7 | 48.3 |
| 2 | -16.7 | 7.5 | 51.7 |
| 3 | -16.1 | 8 | 55.2 |
| 4 | -15.6 | 8.5 | 58.6 |
| 5 | -15 | 9.1 | 62.7 |
| 6 | -14.4 | 9.6 | 66.2 |
| 7 | -13.9 | 10.2 | 70.3 |
| 8 | -13.3 | 10.8 | 74.5 |
| 9 | -12.8 | 11.3 | 77.9 |
| 10 | -12.2 | 11.9 | 82 |
| 11 | -11.7 | 12.5 | 86.2 |
| 12 | -11.1 | 13.1 | 90.3 |
| 13 | -10.6 | 13.8 | 95.1 |
| 14 | -10 | 14.4 | 99.3 |
| 15 | -9.4 | 15 | 103.4 |
| 16 | -8.9 | 15.7 | 108.2 |
| 17 | -8.3 | 16.4 | 113.1 |
| 18 | -7.8 | 17 | 117.2 |
| 19 | -7.2 | 17.7 | 122 |
| 20 | -6.7 | 18.4 | 126.9 |
| 21 | -6.1 | 19.1 | 131.7 |
| 22 | -5.6 | 19.9 | 137.2 |
| 23 | -5 | 20.6 | 142 |
| 24 | -4.4 | 21.3 | 146.9 |
| 25 | -3.9 | 22.1 | 152.4 |
| 26 | -3.3 | 22.9 | 157.9 |
| 27 | -2.8 | 23.7 | 163.4 |
| 28 | -2.2 | 24.5 | 168.9 |
| 29 | -1.7 | 25.3 | 174.4 |
| 30 | -1.1 | 26.1 | 180 |
| 31 | -0.6 | 26.9 | 185.5 |
| 32 | 0 | 27.8 | 191.7 |
| 33 | 0.6 | 28.6 | 197.2 |
| 34 | 1.1 | 29.5 | 203.4 |
| 35 | 1.7 | 30.4 | 209.6 |
| 36 | 2.2 | 31.3 | 215.8 |
| 37 | 2.8 | 32.2 | 222 |
| 38 | 3.3 | 33.1 | 228.2 |
| 39 | 3.9 | 34.1 | 235.1 |
| 40 | 4.4 | 35 | 241.3 |
| 41 | 5 | 36 | 248.2 |
| 42 | 5.6 | 37 | 255.1 |
| 43 | 6.1 | 38 | 262 |
| 44 | 6.7 | 39 | 268.9 |
| 45 | 7.2 | 40.1 | 276.5 |
| 46 | 7.8 | 41.1 | 283.4 |
| 47 | 8.3 | 42.2 | 291 |
| 48 | 8.9 | 43.2 | 297.9 |
| 49 | 9.4 | 44.3 | 305.4 |
| 50 | 10 | 45.4 | 313 |
| 51 | 10.6 | 46.6 | 321.3 |
| 52 | 11.1 | 47.7 | 328.9 |
| 53 | 11.7 | 48.9 | 337.2 |
| 54 | 12.2 | 50 | 344.7 |
| 55 | 12.8 | 51.2 | 353 |
| 56 | 13.3 | 52.4 | 361.3 |
| 57 | 13.9 | 53.6 | 369.6 |
| 58 | 14.4 | 54.9 | 378.5 |
| 59 | 15 | 56.1 | 386.8 |
| 60 | 15.6 | 57.4 | 395.8 |
| 61 | 16.1 | 58.7 | 404.7 |
| 62 | 16.7 | 60 | 413.7 |
| 63 | 17.2 | 61.3 | 422.6 |
| 64 | 17.8 | 62.7 | 432.3 |
| 65 | 18.3 | 64 | 441.3 |
| 66 | 18.9 | 65.4 | 450.9 |
| 67 | 19.4 | 66.8 | 460.6 |
| 68 | 20 | 68.2 | 470.2 |
| 69 | 20.6 | 69.7 | 480.6 |
| 70 | 21.1 | 71.1 | 490.2 |
| 71 | 21.7 | 72.6 | 500.6 |
| 72 | 22.2 | 74.1 | 510.9 |
| 73 | 22.8 | 75.6 | 521.2 |
| 74 | 23.3 | 77.1 | 531.6 |
| 75 | 23.9 | 78.7 | 542.6 |
| 76 | 24.4 | 80.2 | 553 |
| 77 | 25 | 81.8 | 564 |
| 78 | 25.6 | 83.4 | 575 |
| 79 | 26.1 | 85 | 586.1 |
| 80 | 26.7 | 86.7 | 597.8 |
| 81 | 27.2 | 88.4 | 609.5 |
| 82 | 27.8 | 90 | 620.5 |
| 83 | 28.3 | 91.8 | 632.9 |
| 84 | 28.9 | 93.5 | 644.7 |
| 85 | 29.4 | 95.2 | 656.4 |
| 86 | 30 | 97 | 668.8 |
| 87 | 30.6 | 98.8 | 681.2 |
| 88 | 31.1 | 100.6 | 693.6 |
| 89 | 31.7 | 102.5 | 706.7 |
| 90 | 32.2 | 104.3 | 719.1 |
| 91 | 32.8 | 106.2 | 732.2 |
| 92 | 33.3 | 108.1 | 745.3 |
| 93 | 33.9 | 110 | 758.4 |
| 94 | 34.4 | 112 | 772.2 |
| 95 | 35 | 114 | 786 |
| 96 | 35.6 | 115.9 | 799.1 |
| 97 | 36.1 | 118 | 813.6 |
| 98 | 36.7 | 120 | 827.4 |
| 99 | 37.2 | 122.1 | 841.9 |
| 100 | 37.8 | 124.2 | 856.3 |
| 101 | 38.3 | 126.3 | 870.8 |
| 102 | 38.9 | 128.4 | 885.3 |
| 103 | 39.4 | 130.6 | 900.5 |
| 104 | 40 | 132.8 | 915.6 |
| 105 | 40.6 | 135 | 930.8 |
| 106 | 41.1 | 137.2 | 946 |
| 107 | 41.7 | 139.5 | 961.8 |
| 108 | 42.2 | 141.7 | 977 |
| 109 | 42.8 | 144 | 992.8 |
| 110 | 43.3 | 146.4 | 1009.4 |
| 111 | 43.9 | 148.7 | 1025.3 |
| 112 | 44.4 | 151.1 | 1041.8 |
| 113 | 45 | 153.5 | 1058.3 |
| 114 | 45.6 | 156 | 1075.6 |
| 115 | 46.1 | 158.4 | 1092.1 |
| 116 | 46.7 | 160.9 | 1109.4 |
| 117 | 47.2 | 163.5 | 1127.3 |
| 118 | 47.8 | 166 | 1144.5 |
| 119 | 48.3 | 168.6 | 1162.5 |
| 120 | 48.9 | 171.2 | 1180.4 |
| 121 | 49.4 | 173.8 | 1198.3 |
| 122 | 50 | 176.5 | 1216.9 |
| 123 | 50.6 | 179.1 | 1234.9 |
| 124 | 51.1 | 181.8 | 1253.5 |
| 125 | 51.7 | 184.6 | 1272.8 |
| 126 | 52.2 | 187.4 | 1292.1 |
| 127 | 52.8 | 190.2 | 1311.4 |
| 128 | 53.3 | 193 | 1330.7 |
| 129 | 53.9 | 195.8 | 1350 |
| 130 | 54.4 | 198.7 | 1370 |
| 131 | 55 | 201.6 | 1390 |
| 132 | 55.6 | 204.6 | 1410.7 |
| 133 | 56.1 | 207.6 | 1431.4 |
| 134 | 56.7 | 210.6 | 1452 |
| 135 | 57.2 | 213.6 | 1472.7 |
| 136 | 57.8 | 216.7 | 1494.1 |
| 137 | 58.3 | 219.8 | 1515.5 |
| 138 | 58.9 | 222.9 | 1536.8 |
| 139 | 59.4 | 226 | 1558.2 |
| 140 | 60 | 229.2 | 1580.3 |
| 141 | 60.6 | 232.5 | 1603 |
| 142 | 61.1 | 235.7 | 1625.1 |
| 143 | 61.7 | 239 | 1647.8 |
| 144 | 62.2 | 242.3 | 1670.6 |
| 145 | 62.8 | 245.7 | 1694 |
| 146 | 63.3 | 249.1 | 1717.5 |
| 147 | 63.9 | 252.5 | 1740.9 |
| 148 | 64.4 | 255.9 | 1764.4 |
| 149 | 65 | 259.4 | 1788.5 |
| 150 | 65.6 | 262.9 | 1812.6 |
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. 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.