R404A is one of the most commonly used refrigerants. This class of refrigerants (HFCs like R404A or R134A) were introduced in the 90s and 2000s to replace the harmful CFCs. Of course, as with every refrigerant, you need to use the R404A PT chart to get an idea of what kind of pressure you are working with at certain temperatures.
404R pressure temperature chart is quite simple to understand. This is a table that tells you precisely what the pressure of R404A is at a certain temperature. At the low end, the pressure of 404A is 0.9 psig. At the high end, the pressure of 404A is 456.8 psig. We are, of course, talking about 404A liquid pressure.
Example: What is the pressure of R404A at 85°F? Just check the R404A PT chart below and you will see that the pressure of 404A liquid at 85°F is 189.5 psig and the pressure of 404A vapor is 187.5 psig at the same temperature.
Here it’s worth noting that the 404A PT chart includes both liquid and vapor (gas) pressures. The difference between these two pressures is quite insignificant and in practice, we usually just take the pressure of the 404A refrigerant in liquid state for various calculations.
Since we use a gauge meter to measure 404A pressures, the unit we use is not psi (pounds per square inch) but psig (pounds per square inch gauge). That’s how we can measure what is the R404A pressure on a 70-degree, 80-degree, 90-degree, and 100-degree day (you will find all of these examples under the chart).
Note: For on-site use, we include a printable R404A PT chart in PDF form at the end of the article.
Here is the full R404A PT chart from the low end (-49°F) to the high end (150°F):
404A Pressure Temperature Chart
| Temperature (°F): | Temperature (°C): | 404A Liquid Pressure (psig): | 404A Vapor Pressure (psig): |
| -49°F | -45.0°C | 0.9 psig | 0.3 psig |
| -48°F | -44.4°C | 1.3 psig | 0.7 psig |
| -47°F | -43.9°C | 1.7 psig | 1.2 psig |
| -46°F | -43.3°C | 2.1 psig | 1.6 psig |
| -45°F | -42.8°C | 2.6 psig | 2.0 psig |
| -44°F | -42.2°C | 3.0 psig | 2.4 psig |
| -43°F | -41.7°C | 3.5 psig | 2.9 psig |
| -42°F | -41.1°C | 4.0 psig | 3.4 psig |
| -41°F | -40.6°C | 4.4 psig | 3.8 psig |
| -40°F | -40.0°C | 4.9 psig | 4.3 psig |
| -39°F | -39.4°C | 5.4 psig | 4.8 psig |
| -38°F | -38.9°C | 5.9 psig | 5.3 psig |
| -37°F | -38.3°C | 6.4 psig | 5.8 psig |
| -36°F | -37.8°C | 7.0 psig | 6.3 psig |
| -35°F | -37.2°C | 7.5 psig | 6.8 psig |
| -34°F | -36.7°C | 8.0 psig | 7.4 psig |
| -33°F | -36.1°C | 8.6 psig | 7.9 psig |
| -32°F | -35.6°C | 9.2 psig | 8.5 psig |
| -31°F | -35.0°C | 9.7 psig | 9.0 psig |
| -30°F | -34.4°C | 10.3 psig | 9.6 psig |
| -29°F | -33.9°C | 10.9 psig | 10.2 psig |
| -28°F | -33.3°C | 11.5 psig | 10.8 psig |
| -27°F | -32.8°C | 12.2 psig | 11.4 psig |
| -26°F | -32.2°C | 12.8 psig | 12.0 psig |
| -25°F | -31.7°C | 13.4 psig | 12.7 psig |
| -24°F | -31.1°C | 14.1 psig | 13.3 psig |
| -23°F | -30.6°C | 14.8 psig | 14.0 psig |
| -22°F | -30.0°C | 15.4 psig | 14.6 psig |
| -21°F | -29.4°C | 16.1 psig | 15.3 psig |
| -20°F | -28.9°C | 16.8 psig | 16.0 psig |
| -19°F | -28.3°C | 17.5 psig | 16.7 psig |
| -18°F | -27.8°C | 18.3 psig | 17.4 psig |
| -17°F | -27.2°C | 19.0 psig | 18.2 psig |
| -16°F | -26.7°C | 19.8 psig | 18.9 psig |
| -15°F | -26.1°C | 20.5 psig | 19.7 psig |
| -14°F | -25.6°C | 21.3 psig | 20.4 psig |
| -13°F | -25.0°C | 22.1 psig | 21.2 psig |
| -12°F | -24.4°C | 22.9 psig | 22.0 psig |
| -11°F | -23.9°C | 23.7 psig | 22.8 psig |
| -10°F | -23.3°C | 24.6 psig | 23.6 psig |
| -9°F | -22.8°C | 25.4 psig | 24.5 psig |
| -8°F | -22.2°C | 26.3 psig | 25.3 psig |
| -7°F | -21.7°C | 27.1 psig | 26.2 psig |
| -6°F | -21.1°C | 28.0 psig | 27.0 psig |
| -5°F | -20.6°C | 28.9 psig | 27.9 psig |
| -4°F | -20.0°C | 29.8 psig | 28.8 psig |
| -3°F | -19.4°C | 30.8 psig | 29.8 psig |
| -2°F | -18.9°C | 31.7 psig | 30.7 psig |
| -1°F | -18.3°C | 32.7 psig | 31.6 psig |
| 0°F | -17.8°C | 33.7 psig | 32.6 psig |
| 1°F | -17.2°C | 34.7 psig | 33.6 psig |
| 2°F | -16.7°C | 35.7 psig | 34.6 psig |
| 3°F | -16.1°C | 36.7 psig | 35.6 psig |
| 4°F | -15.6°C | 37.7 psig | 36.6 psig |
| 5°F | -15.0°C | 38.8 psig | 37.7 psig |
| 6°F | -14.4°C | 39.8 psig | 38.7 psig |
| 7°F | -13.9°C | 40.9 psig | 39.8 psig |
| 8°F | -13.3°C | 42.0 psig | 40.9 psig |
| 9°F | -12.8°C | 43.1 psig | 42.0 psig |
| 10°F | -12.2°C | 44.3 psig | 43.1 psig |
| 11°F | -11.7°C | 45.4 psig | 44.3 psig |
| 12°F | -11.1°C | 46.6 psig | 45.4 psig |
| 13°F | -10.6°C | 47.8 psig | 46.6 psig |
| 14°F | -10.0°C | 49.0 psig | 47.8 psig |
| 15°F | -9.4°C | 50.2 psig | 49.0 psig |
| 16°F | -8.9°C | 51.5 psig | 50.2 psig |
| 17°F | -8.3°C | 52.7 psig | 51.5 psig |
| 18°F | -7.8°C | 54.0 psig | 52.7 psig |
| 19°F | -7.2°C | 55.3 psig | 54.0 psig |
| 20°F | -6.7°C | 56.6 psig | 55.3 psig |
| 21°F | -6.1°C | 57.9 psig | 56.6 psig |
| 22°F | -5.6°C | 59.3 psig | 58.0 psig |
| 23°F | -5.0°C | 60.6 psig | 59.3 psig |
| 24°F | -4.4°C | 62.0 psig | 60.7 psig |
| 25°F | -3.9°C | 63.4 psig | 62.1 psig |
| 26°F | -3.3°C | 64.8 psig | 63.5 psig |
| 27°F | -2.8°C | 66.3 psig | 64.9 psig |
| 28°F | -2.2°C | 67.8 psig | 66.4 psig |
| 29°F | -1.7°C | 69.2 psig | 67.8 psig |
| 30°F | -1.1°C | 70.7 psig | 69.3 psig |
| 31°F | -0.6°C | 72.3 psig | 70.8 psig |
| 32°F | 0°C | 73.8 psig | 72.4 psig |
| 33°F | 0.6°C | 75.4 psig | 73.9 psig |
| 34°F | 1.1°C | 77.0 psig | 75.5 psig |
| 35°F | 1.7°C | 78.6 psig | 77.1 psig |
| 36°F | 2.2°C | 80.2 psig | 78.7 psig |
| 37°F | 2.8°C | 81.8 psig | 80.3 psig |
| 38°F | 3.3°C | 83.5 psig | 82.0 psig |
| 39°F | 3.9°C | 85.2 psig | 83.7 psig |
| 40°F | 4.4°C | 86.9 psig | 85.4 psig |
| 41°F | 5.0°C | 88.6 psig | 87.1 psig |
| 42°F | 5.6°C | 90.4 psig | 88.8 psig |
| 43°F | 6.1°C | 92.2 psig | 90.6 psig |
| 44°F | 6.7°C | 94.0 psig | 92.4 psig |
| 45°F | 7.2°C | 95.8 psig | 94.2 psig |
| 46°F | 7.8°C | 97.6 psig | 96.0 psig |
| 47°F | 8.3°C | 99.5 psig | 97.9 psig |
| 48°F | 8.9°C | 101.4 psig | 99.8 psig |
| 49°F | 9.4°C | 103.3 psig | 101.7 psig |
| 50°F | 10.0°C | 105.3 psig | 103.6 psig |
| 51°F | 10.6°C | 107.2 psig | 105.6 psig |
| 52°F | 11.1°C | 109.2 psig | 107.6 psig |
| 53°F | 11.7°C | 111.2 psig | 109.6 psig |
| 54°F | 12.2°C | 113.3 psig | 111.6 psig |
| 55°F | 12.8°C | 115.3 psig | 113.6 psig |
| 56°F | 13.3°C | 117.4 psig | 115.7 psig |
| 57°F | 13.9°C | 119.5 psig | 117.8 psig |
| 58°F | 14.4°C | 121.7 psig | 119.9 psig |
| 59°F | 15.0°C | 123.8 psig | 122.1 psig |
| 60°F | 15.6°C | 126.0 psig | 124.2 psig |
| 61°F | 16.1°C | 128.2 psig | 126.4 psig |
| 62°F | 16.7°C | 130.5 psig | 128.7 psig |
| 63°F | 17.2°C | 132.7 psig | 130.9 psig |
| 64°F | 17.8°C | 135.0 psig | 133.2 psig |
| 65°F | 18.3°C | 137.3 psig | 135.5 psig |
| 66°F | 18.9°C | 139.7 psig | 137.8 psig |
| 67°F | 19.4°C | 142.0 psig | 140.2 psig |
| 68°F | 20.0°C | 144.4 psig | 142.6 psig |
| 69°F | 20.6°C | 146.9 psig | 145.0 psig |
| 70°F | 21.1°C | 149.3 psig | 147.4 psig |
| 71°F | 21.7°C | 149.3 psig | 147.4 psig |
| 72°F | 22.2°C | 154.3 psig | 152.4 psig |
| 73°F | 22.8°C | 156.8 psig | 154.9 psig |
| 74°F | 23.3°C | 159.4 psig | 157.5 psig |
| 75°F | 23.9°C | 162.0 psig | 160.1 psig |
| 76°F | 24.4°C | 164.6 psig | 162.7 psig |
| 77°F | 25.0°C | 167.3 psig | 165.3 psig |
| 78°F | 25.6°C | 170.0 psig | 168.0 psig |
| 79°F | 26.1°C | 172.7 psig | 170.7 psig |
| 80°F | 26.7°C | 175.4 psig | 173.4 psig |
| 81°F | 27.2°C | 178.2 psig | 176.2 psig |
| 82°F | 27.8°C | 181.0 psig | 179.0 psig |
| 83°F | 28.3°C | 183.8 psig | 181.8 psig |
| 84°F | 29.4°C | 186.7 psig | 184.7 psig |
| 85°F | 30.0°C | 189.5 psig | 187.5 psig |
| 86°F | 30.6°C | 192.5 psig | 190.4 psig |
| 87°F | 31.1°C | 195.4 psig | 193.4 psig |
| 88°F | 31.7°C | 198.4 psig | 196.4 psig |
| 89°F | 31.7°C | 201.4 psig | 199.4 psig |
| 90°F | 32.2°C | 204.5 psig | 202.4 psig |
| 91°F | 32.8°C | 207.6 psig | 205.5 psig |
| 92°F | 33.3°C | 210.7 psig | 208.6 psig |
| 93°F | 33.9°C | 213.8 psig | 211.7 psig |
| 94°F | 34.4°C | 217.0 psig | 214.9 psig |
| 95°F | 35.0°C | 220.2 psig | 218.1 psig |
| 96°F | 35.6°C | 223.4 psig | 221.4 psig |
| 97°F | 36.1°C | 226.7 psig | 224.6 psig |
| 98°F | 36.7°C | 230.0 psig | 227.9 psig |
| 99°F | 37.2°C | 233.4 psig | 231.3 psig |
| 100°F | 37.8°C | 236.8 psig | 234.2 psig |
| 105°F | 40.6°C | 254.2 psig | 252.1 psig |
| 110°F | 43.3°C | 272.5 psig | 270.4 psig |
| 115°F | 46.1°C | 291.8 psig | 289.6 psig |
| 120°F | 48.9°C | 312.1 psig | 309.9 psig |
| 125°F | 51.7°C | 333.3 psig | 331.2 psig |
| 130°F | 54.4°C | 355.7 psig | 353.5 psig |
| 135°F | 57.2°C | 379.1 psig | 377.0 psig |
| 140°F | 60.0°C | 403.7 psig | 401.7 psig |
| 145°F | 62.8°C | 429.6 psig | 427.7 psig |
| 150°F | 65.6°C | 456.8 psig | 455.1 psig |
Let’s look at some cases to illustrate how you can use this PT chart for R404A:
R404A Pressures On A 70-Degree Day?
If you check the chart above, you can see that the pressure of the liquid R404A refrigerant is 149.3 psig. If you are measuring the pressure of a 404A gas (vapor), your gauge meter should read 147.4 psig on a 70-degree day. The difference between liquid and vapor pressure here is 1.7 psig.
R404A Pressures On A 80-Degree Day?
If you check the chart above, you can see that the pressure of the liquid R404A refrigerant is 175.4 psig. If you are measuring the pressure of a 404A gas (vapor), your gauge meter should read 173.4 psig on an 80-degree day. The difference between liquid and vapor pressure here is 1.7 psig.
R404A Pressures On A 90-Degree Day?
If you check the chart above, you can see that the pressure of the liquid R404A refrigerant is 204.5 psig. If you are measuring the pressure of a 404A gas (vapor), your gauge meter should read 202.4 psig on a 90-degree day. The difference between liquid and vapor pressure here is 1.9 psig.
R404A Pressures On A 100-Degree Day?
If you check the chart above, you can see that the pressure of the liquid R404A refrigerant is 236.8 psig. If you are measuring the pressure of a 404A gas (vapor), your gauge meter should read 234.2 psig on a 100-degree day. The difference between liquid and vapor pressure here is 2.6 psig.
R404A PT Chart PDF (Printable PDF For On-Site Use)
As promised, you can get the printable PDF version of the R404A PT chart here if you need it on-site:
Hopefully, this illustrates the correlation between pressure and temperature for an R404A refrigerant. You can check similar PT charts for: