R-422D PT Chart
A1 GWP 2729Zeotropic blend (R-125/R-134a/R-600a, 85.1/11.5/3.4%). HFC Blend.
About R-422D
R-422D (sold as MO29) is an R-22 retrofit blend that can often run with the existing mineral oil, because its small isobutane content helps oil return. Capacity is a little lower than R-22, and the glide is roughly 6–8°F, so charge it as a liquid and set superheat against the dew column.
Saturation pressures at typical operating points, taken from the table below:
- Evaporator (AC, 40°F): 76.5 PSIG liquid / 66.5 PSIG vapor
- Condensing (110°F): 245.8 PSIG liquid / 231.0 PSIG vapor
The table covers -80°F to 160°F in 5°F steps. Below about -46°F the liquid saturation pressure is below atmospheric, so gauges read in vacuum (shown in blue in the table).
R-422D Pressure-Temperature Graph (Bubble & Dew)
R-422D Saturation Pressure Table
R-422D is a zeotropic blend with temperature glide, so it has two saturation pressures at each temperature. Use Vapor (dew) PSIG to find evaporator saturation for superheat, and Liquid (bubble) PSIG to find condenser saturation for subcooling. PSIA, kPa and bar columns are liquid (bubble) pressures. Blue values indicate vacuum.
| °F | °C | Liquid PSIG (bubble) |
Vapor PSIG (dew) |
PSIA | kPa | bar |
|---|---|---|---|---|---|---|
| -80 | -62.2 | -9.2 | -10.8 | 5.51 | 38.0 | 0.38 |
| -75 | -59.4 | -8.2 | -10.1 | 6.45 | 44.5 | 0.445 |
| -70 | -56.7 | -7.2 | -9.2 | 7.51 | 51.8 | 0.518 |
| -65 | -53.9 | -6.0 | -8.3 | 8.71 | 60.1 | 0.601 |
| -60 | -51.1 | -4.6 | -7.2 | 10.06 | 69.4 | 0.694 |
| -55 | -48.3 | -3.1 | -5.9 | 11.57 | 79.8 | 0.798 |
| -50 | -45.6 | -1.4 | -4.5 | 13.26 | 91.4 | 0.914 |
| -45 | -42.8 | 0.4 | -2.9 | 15.13 | 104.3 | 1.043 |
| -40 | -40.0 | 2.5 | -1.1 | 17.2 | 118.6 | 1.186 |
| -35 | -37.2 | 4.8 | 0.8 | 19.5 | 134.4 | 1.344 |
| -30 | -34.4 | 7.3 | 3.0 | 22.02 | 151.8 | 1.518 |
| -25 | -31.7 | 10.1 | 5.4 | 24.79 | 170.9 | 1.709 |
| -20 | -28.9 | 13.1 | 8.1 | 27.83 | 191.9 | 1.919 |
| -15 | -26.1 | 16.4 | 11.1 | 31.14 | 214.7 | 2.147 |
| -10 | -23.3 | 20.1 | 14.3 | 34.76 | 239.6 | 2.396 |
| -5 | -20.6 | 24.0 | 17.8 | 38.68 | 266.7 | 2.667 |
| 0 | -17.8 | 28.2 | 21.7 | 42.94 | 296.1 | 2.961 |
| 5 | -15.0 | 32.8 | 25.9 | 47.55 | 327.8 | 3.278 |
| 10 | -12.2 | 37.8 | 30.4 | 52.52 | 362.1 | 3.621 |
| 15 | -9.4 | 43.2 | 35.4 | 57.88 | 399.1 | 3.991 |
| 20 | -6.7 | 48.9 | 40.7 | 63.64 | 438.8 | 4.388 |
| 25 | -3.9 | 55.1 | 46.5 | 69.83 | 481.5 | 4.815 |
| 30 | -1.1 | 61.8 | 52.7 | 76.47 | 527.2 | 5.272 |
| 35 | 1.7 | 68.9 | 59.4 | 83.57 | 576.2 | 5.762 |
| 40 | 4.4 | 76.5 | 66.5 | 91.15 | 628.4 | 6.284 |
| 45 | 7.2 | 84.5 | 74.2 | 99.23 | 684.2 | 6.842 |
| 50 | 10.0 | 93.2 | 82.4 | 107.85 | 743.6 | 7.436 |
| 55 | 12.8 | 102.3 | 91.1 | 117.01 | 806.7 | 8.067 |
| 60 | 15.6 | 112.0 | 100.4 | 126.74 | 873.8 | 8.738 |
| 65 | 18.3 | 122.4 | 110.3 | 137.06 | 945.0 | 9.45 |
| 70 | 21.1 | 133.3 | 120.9 | 148.0 | 1020.4 | 10.204 |
| 75 | 23.9 | 144.9 | 132.1 | 159.57 | 1100.2 | 11.002 |
| 80 | 26.7 | 157.1 | 144.0 | 171.81 | 1184.6 | 11.846 |
| 85 | 29.4 | 170.0 | 156.5 | 184.73 | 1273.7 | 12.737 |
| 90 | 32.2 | 183.7 | 169.9 | 198.37 | 1367.7 | 13.677 |
| 95 | 35.0 | 198.0 | 183.9 | 212.73 | 1466.8 | 14.668 |
| 100 | 37.8 | 213.2 | 198.8 | 227.87 | 1571.1 | 15.711 |
| 105 | 40.6 | 229.1 | 214.5 | 243.78 | 1680.8 | 16.808 |
| 110 | 43.3 | 245.8 | 231.0 | 260.52 | 1796.2 | 17.962 |
| 115 | 46.1 | 263.4 | 248.5 | 278.11 | 1917.5 | 19.175 |
| 120 | 48.9 | 281.9 | 266.9 | 296.56 | 2044.7 | 20.447 |
| 125 | 51.7 | 301.2 | 286.2 | 315.93 | 2178.3 | 21.783 |
| 130 | 54.4 | 321.5 | 306.5 | 336.24 | 2318.3 | 23.183 |
| 135 | 57.2 | 342.8 | 328.0 | 357.53 | 2465.1 | 24.651 |
| 140 | 60.0 | 365.1 | 350.5 | 379.84 | 2618.9 | 26.189 |
| 145 | 62.8 | 388.5 | 374.2 | 403.2 | 2780.0 | 27.8 |
| 150 | 65.6 | 413.0 | 399.2 | 427.67 | 2948.7 | 29.487 |
| 155 | 68.3 | 438.6 | 425.5 | 453.28 | 3125.3 | 31.253 |
| 160 | 71.1 | 465.4 | — | 480.09 | 3310.1 | 33.101 |
Properties
| ASHRAE Designation | 422D |
| Safety Classification | A1 (non-flammable, low toxicity) |
| GWP (AR4, 100-yr) | 2729 |
| ODP | 0 |
| Molecular Weight | 109.94 g/mol |
| Boiling Point (1 atm) | -46.1°F / -43.4°C |
| Critical Temperature | 172.6°F / 78.1°C |
| Critical Pressure | 551.0 psia / 37.99 bar |
| Category | HFC Blend |
Common Applications
- R-22 retrofit
- AC systems