What are the 404a operating pressures? Well, in this guide we provide you with a 404 pt chart which shows the common operating pressures for 404a at different temperatures.
404a Operating Pressure Chart (404a pt chart)
| Temp(°F) | Liquid Pressure (psi) | Vapor Pressure (psi) | Temp (°C) |
| -49 | 0.9 | 0.3 | -45 |
| -48 | 1.3 | 0.7 | -44.4 |
| -47 | 1.7 | 1.2 | -43.9 |
| -46 | 2.1 | 1.6 | -43.3 |
| -45 | 2.6 | 2 | -42.8 |
| -44 | 3 | 2.4 | -42.2 |
| -43 | 3.5 | 2.9 | -41.7 |
| -42 | 4 | 3.4 | -41.1 |
| -41 | 4.4 | 3.8 | -40.6 |
| -40 | 4.9 | 4.3 | -40 |
| -39 | 5.4 | 4.8 | -39.4 |
| -38 | 5.9 | 5.3 | -38.9 |
| -37 | 6.4 | 5.8 | -38.3 |
| -36 | 7 | 6.3 | -37.8 |
| -35 | 7.5 | 6.8 | -37.2 |
| -34 | 8 | 7.4 | -36.7 |
| -33 | 8.6 | 7.9 | -36.1 |
| -32 | 9.2 | 8.5 | -35.6 |
| -31 | 9.7 | 9 | -35 |
| -30 | 10.3 | 9.6 | -34.4 |
| -29 | 10.9 | 10.2 | -33.9 |
| -28 | 11.5 | 10.8 | -33.3 |
| -27 | 12.2 | 11.4 | -32.8 |
| -26 | 12.8 | 12 | -32.2 |
| -25 | 13.4 | 12.7 | -31.7 |
| -24 | 14.1 | 13.3 | -31.1 |
| -23 | 14.8 | 14 | -30.6 |
| -22 | 15.4 | 14.6 | -30 |
| -21 | 16.1 | 15.3 | -29.4 |
| -20 | 16.8 | 16 | -28.9 |
| -19 | 17.5 | 16.7 | -28.3 |
| -18 | 18.3 | 17.4 | -27.8 |
| -17 | 19 | 18.2 | -27.2 |
| -16 | 19.8 | 18.9 | -26.7 |
| -15 | 20.5 | 19.7 | -26.1 |
| -14 | 21.3 | 20.4 | -25.6 |
| -13 | 22.1 | 21.2 | -25 |
| -12 | 22.9 | 22 | -24.4 |
| -11 | 23.7 | 22.8 | -23.9 |
| 10 | 24.6 | 24.6 | -23.3 |
| -9 | 25.4 | 24.5 | -22.8 |
| -8 | 26.3 | 25.3 | -22.2 |
| -7 | 27.1 | 26.2 | -21.7 |
| -6 | 28 | 27 | -21.1 |
| -5 | 28.9 | 27.9 | -20.6 |
| -4 | 29.8 | 28.8 | -20 |
| -3 | 30.8 | 29.8 | – 19.4 |
| -2 | 31.7 | 30.7 | – 18.9 |
| -1 | 32.7 | 31.6 | -18.3 |
| 0 | 33.7 | 32.6 | -17.8 |
| 1 | 34.7 | 33.6 | -17.2 |
| 2 | 35.7 | 34.6 | – 16.7 |
| 3 | 36.7 | 35.6 | – 25.6 |
| 4 | 37.7 | 36.6 | -15.6 |
| 5 | 38.8 | 37.7 | -15 |
| 6 | 39.8 | 38.7 | -14.4 |
| 7 | 40.9 | 39.8 | -13.9 |
| 8 | 42 | 40.9 | -13.3 |
| 9 | 43.1 | 42 | -12.8 |
| 10 | 44.3 | 43.1 | -12.2 |
| 11 | 45.4 | 44.3 | -11.7 |
| 12 | 46.6 | 45.4 | -11.1 |
| 13 | 47.8 | 46.6 | -10.6 |
| 14 | 49 | 47.8 | -10 |
| 15 | 50.2 | 49 | -9.4 |
| 16 | 51.5 | 50.2 | -8.9 |
| 17 | 52.7 | 51.5 | -8.3 |
| 18 | 54 | 52.7 | -7.8 |
| 19 | 55.3 | 54 | -7.2 |
| 20 | 56.6 | 55.3 | -6.7 |
| 21 | 57.9 | 56.6 | -6.1 |
| 22 | 59.3 | 58 | -5.6 |
| 23 | 60.6 | 59.3 | -5 |
| 24 | 62 | 60.7 | -4.4 |
| 25 | 63.4 | 62.1 | -3.9 |
| 26 | 64.8 | 63.5 | -3.3 |
| 27 | 66.3 | 64.9 | -2.8 |
| 28 | 67.8 | 66.4 | -2.2 |
| 29 | 69.2 | 67.8 | -1.7 |
| 30 | 70.7 | 69.3 | -1,1 |
| 31 | 72.3 | 70.8 | -0.6 |
| 32 | 73.8 | 72.4 | 0 |
| 33 | 75.4 | 73.9 | 0.6 |
| 34 | 77 | 75.5 | 1.1 |
| 35 | 78.6 | 77.1 | 1.7 |
| 36 | 80.2 | 78.7 | 2.2 |
| 37 | 81,8 | 80.3 | 2.8 |
| 38 | 83.5 | 82 | 3.3 |
| 39 | 85.2 | 83.7 | 3.9 |
| 40 | 86.9 | 85.4 | 4.4 |
| 41 | 88.6 | 87.1 | 5 |
| 42 | 90.4 | 88.8 | 5.6 |
| 43 | 92.2 | 90.6 | 6.1 |
| 44 | 94 | 92.4 | 6.7 |
| 45 | 95.8 | 94.2 | 7.2 |
| 46 | 97.6 | 96 | 7.8 |
| 47 | 99.5 | 97.9 | 8,3 |
| 48 | 101.4 | 99.8 | 8.9 |
| 49 | 103.3 | 101.7 | 9.4 |
| 50 | 105.3 | 103.6 | 10 |
| 51 | 107.2 | 105.6 | 10.6 |
| 52 | 109.2 | 107.6 | 11.1 |
| 53 | 11.2 | 109.6 | 11.7 |
| 54 | 113.3 | 111.6 | 12.2 |
| 55 | 115.3 | 113.6 | 12.8 |
| 56 | 117.4 | 115.7 | 13.3 |
| 57 | 119.5 | 117.8 | 13.9 |
| 58 | 121.7 | 119.9 | 14.4 |
| 59 | 123.8 | 122.1 | 15 |
| 60 | 126 | 124.2 | 15.6 |
| 61 | 128.2 | 126.4 | 16.1 |
| 62 | 130.5 | 128.7 | 16.7 |
| 63 | 132.7 | 130.9 | 17.2 |
| 64 | 135 | 133.2 | 17.8 |
| 65 | 137.3 | 135.5 | 18.3 |
| 66 | 139.7 | 137.8 | 18,9 |
| 67 | 142 | 140.2 | 19.4 |
| 68 | 144.4 | 142.6 | 20 |
| 69 | 146.9 | 145 | 20.6 |
| 70 | 149.3 | 147.4 | 21.1 |
| 71 | 151.8 | 149.9 | 21.7 |
| 72 | 154.3 | 152.4 | 22.2 |
| 73 | 156.8 | 154.9 | 22.8 |
| 74 | 159.4 | 157.5 | 23.3 |
| 75 | 162 | 160.1 | 23.9 |
| 76 | 164.6 | 162.7 | 24.4 |
| 77 | 167.3 | 165.3 | 25 |
| 78 | 170 | 168 | 25.6 |
| 79 | 172.7 | 170.7 | 26.1 |
| 80 | 175.4 | 173.4 | 26.7 |
| 81 | 178.2 | 176.2 | 27.2 |
| 82 | 181 | 179 | 27.8 |
| 83 | 183.8 | 181.8 | 28.3 |
| 84 | 186.7 | 184.7 | 28.9 |
| 85 | 189.5 | 187.5 | 29.4 |
| 86 | 192.5 | 190.4 | 30 |
| 87 | 195.4 | 193.4 | 30.6 |
| 88 | 198.4 | 196.4 | 31.1 |
| 89 | 201.4 | 199.4 | 31.7 |
| 90 | 204.5 | 202.4 | 32.2 |
| 91 | 207.6 | 205.5 | 32.8 |
| 92 | 210.7 | 208.6 | 33.3 |
| 93 | 213.8 | 211.7 | 33.9 |
| 94 | 217 | 214.9 | 34.4 |
| 95 | 220.2 | 218.1 | 35 |
| 96 | 223.4 | 221.4 | 35.6 |
| 97 | 226.7 | 224.6 | 36.1 |
| 98 | 230 | 227.9 | 36.7 |
| 99 | 233.4 | 231 | 37.2 |
| 100 | 236.8 | 234.6 | 37.8 |
| 101 | 240.2 | 238.1 | 38.3 |
| 102 | 243.6 | 241.5 | 38.9 |
| 103 | 247.1 | 245 | 39.4 |
| 104 | 250.6 | 248.5 | 40 |
| 105 | 254.2 | 252.1 | 40.5 |
| 106 | 257.8 | 255.6 | 41.1 |
| 107 | 261.4 | 259 .3 | 41.7 |
| 108 | 265.1 | 262.9 | 42.2 |
| 109 | 268.8 | 266.6 | 42.8 |
| 110 | 272.5 | 270.4 | 43.3 |
| 111 | 276.3 | 274.1 | 43.9 |
| 112 | 280.1 | 278 | 44.4 |
| 113 | 284 | 281.8 | 45 |
| 114 | 287.9 | 285.7 | 45.6 |
| 115 | 291.8 | 289.6 | 46.1 |
| 116 | 295.8 | 293.6 | 46.7 |
| 117 | 299.8 | 297.6 | 47.2 |
| 118 | 303.8 | 301.7 | 47.8 |
| 119 | 307.9 | 305.8 | 48.3 |
| 120 | 312.1 | 309.9 | 48.9 |
| 121 | 119.1 | 3141 | 494 |
| 122 | 320.4 | 318.3 | 50 |
| 123 | 324.7 | 322.5 | 50.6 |
| 124 | 329 | 326.8 | 51.1 |
| 125 | 333.3 | 331.2 | 51.7 |
| 126 | 337.7 | 335.6 | 52.2 |
| 127 | 342.1 | 340 | 52.8 |
| 128 | 346.6 | 344.4 | 53.3 |
| 129 | 351.1 | 349 | 53.9 |
| 130 | 355.7 | 353.5 | 54.4 |
| 131 | 360.2 | 35.1 | 55 |
| 132 | 364.9 | 362.8 | 55.6 |
| 133 | 369.6 | 367.5 | 56.1 |
| 134 | 374.3 | 372.2 | 56.7 |
| 135 | 379.1 | 377 | 57.2 |
| 136 | 383.9 | 381.9 | 57.8 |
| 137 | 388.8 | 386.8 | 58.3 |
| 138 | 393.7 | 391.7 | 58.9 |
| 139 | 398.7 | 396.7 | 59.4 |
| 140 | 403.7 | 401.7 | 60 |
| 141 | 408.8 | 406.8 | 60.6 |
| 142 | 413.9 | 412 | 61.1 |
| 143 | 419.1 | 417.1 | 61.7 |
| 144 | 424.3 | 422.4 | 62.2 |
| 145 | 429.6 | 427.7 | 62.8 |
| 146 | 434.9 | 433.1 | 63.3 |
| 147 | 440.3 | 438.5 | 63.9 |
| 148 | 445.8 | 443.9 | 64.4 |
| 149 | 451.3 | 449.5 | 65 |
| 150 | 456.8 | 455.1 | 65.6 |
Read also: R410a Pressure Chart High and Low Side
psi: Pound per square inch, unit of pressure
For the complete reference on thermostat wiring terminals, wire colors, and heat pump configurations, see the Thermostat Wiring Guide.
FAQ
What is the normal suction pressure on a 404a walk in the freezer?
The normal suction pressure on a 404 a walk in freezer is around 10-20 psig (10 is ideal) on the suction side if working properly.
And the high side is about 180 or so. High suction pressure could cause the evaporator coils to freeze.
