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R-408A pressure-temperature chart and data
R-125 / R-143a / R-22. Safety class A1, GWP 3,152. Retrofit for R-502.
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R-408A data sheet
| Made of | R-125 7 / R-143a 46 / R-22 47 (mass %) |
|---|---|
| Type | HCFC blend |
| Safety class | A1 — lower toxicity, does not burn |
| Ozone depletion (ODP) | 0.026 |
| Global warming (GWP, 100 yr) | 3,152 |
| Boils at 1 atm | -47.6 °F (-44.2 °C) |
| Critical temperature | 182.6 °F (83.7 °C) |
| Temperature glide | none / very small |
| Low side at 5 °F evaporating | 33.6 psig (232 kPa) |
| High side at 86 °F condensing | 176 psig (1212 kPa) |
| Old cylinder colour | Medium purple |
| Oil | AB / POE |
| Used for | Retrofit for R-502. |
- Ozone-depleting: venting is illegal. Recover it and send it to a licensed reclaimer.
- Pressures for this blend come from a simplified mixing model, within about 1 to 2 psi of the maker’s chart. Check the maker’s chart for charging.
Pressures are saturation values from reference equations of state. Real pressures change with load and airflow. GWP is the IPCC AR4 100-year value (blends calculated from their ingredients). Cylinder colours were an old AHRI code; since 2020 new cylinders are all one colour with the name on the label, so always read the label, never go by colour.
R-408A pressure / temperature chart
| °F | °C | Dew psig (vapour) | Bubble psig (liquid) | Dew kPa | Bubble kPa |
|---|---|---|---|---|---|
| -60 | -51.1 | V 9.0 | V 8.5 | -31 | -29 |
| -59 | -50.6 | V 8.4 | V 7.9 | -29 | -27 |
| -58 | -50.0 | V 7.8 | V 7.3 | -26 | -25 |
| -57 | -49.4 | V 7.2 | V 6.7 | -24 | -23 |
| -56 | -48.9 | V 6.6 | V 6.0 | -22 | -20 |
| -55 | -48.3 | V 5.9 | V 5.4 | -20 | -18 |
| -54 | -47.8 | V 5.2 | V 4.7 | -18 | -16 |
| -53 | -47.2 | V 4.6 | V 4.0 | -15 | -14 |
| -52 | -46.7 | V 3.8 | V 3.3 | -13 | -11 |
| -51 | -46.1 | V 3.1 | V 2.6 | -11 | -9 |
| -50 | -45.6 | V 2.4 | V 1.8 | -8 | -6 |
| -49 | -45.0 | V 1.7 | V 1.1 | -6 | -4 |
| -48 | -44.4 | V 0.9 | V 0.3 | -3 | -1 |
| -47 | -43.9 | V 0.1 | 0.2 | -0 | 2 |
| -46 | -43.3 | 0.3 | 0.6 | 2 | 4 |
| -45 | -42.8 | 0.7 | 1.0 | 5 | 7 |
| -44 | -42.2 | 1.1 | 1.4 | 8 | 10 |
| -43 | -41.7 | 1.5 | 1.9 | 11 | 13 |
| -42 | -41.1 | 2.0 | 2.3 | 14 | 16 |
| -41 | -40.6 | 2.4 | 2.7 | 16 | 19 |
| -40 | -40.0 | 2.8 | 3.2 | 19 | 22 |
| -39 | -39.4 | 3.3 | 3.6 | 23 | 25 |
| -38 | -38.9 | 3.7 | 4.1 | 26 | 28 |
| -37 | -38.3 | 4.2 | 4.5 | 29 | 31 |
| -36 | -37.8 | 4.7 | 5.0 | 32 | 35 |
| -35 | -37.2 | 5.2 | 5.5 | 36 | 38 |
| -34 | -36.7 | 5.6 | 6.0 | 39 | 42 |
| -33 | -36.1 | 6.2 | 6.5 | 42 | 45 |
| -32 | -35.6 | 6.7 | 7.0 | 46 | 49 |
| -31 | -35.0 | 7.2 | 7.6 | 50 | 52 |
| -30 | -34.4 | 7.7 | 8.1 | 53 | 56 |
| -29 | -33.9 | 8.3 | 8.7 | 57 | 60 |
| -28 | -33.3 | 8.8 | 9.2 | 61 | 64 |
| -27 | -32.8 | 9.4 | 9.8 | 65 | 67 |
| -26 | -32.2 | 9.9 | 10.4 | 69 | 71 |
| -25 | -31.7 | 10.5 | 10.9 | 73 | 75 |
| -24 | -31.1 | 11.1 | 11.6 | 77 | 80 |
| -23 | -30.6 | 11.7 | 12.2 | 81 | 84 |
| -22 | -30.0 | 12.3 | 12.8 | 85 | 88 |
| -21 | -29.4 | 13.0 | 13.4 | 89 | 92 |
| -20 | -28.9 | 13.6 | 14.1 | 94 | 97 |
| -19 | -28.3 | 14.3 | 14.7 | 98 | 101 |
| -18 | -27.8 | 14.9 | 15.4 | 103 | 106 |
| -17 | -27.2 | 15.6 | 16.1 | 107 | 111 |
| -16 | -26.7 | 16.3 | 16.7 | 112 | 115 |
| -15 | -26.1 | 17.0 | 17.4 | 117 | 120 |
| -14 | -25.6 | 17.7 | 18.2 | 122 | 125 |
| -13 | -25.0 | 18.4 | 18.9 | 127 | 130 |
| -12 | -24.4 | 19.1 | 19.6 | 132 | 135 |
| -11 | -23.9 | 19.9 | 20.4 | 137 | 140 |
| -10 | -23.3 | 20.6 | 21.1 | 142 | 146 |
| -9 | -22.8 | 21.4 | 21.9 | 147 | 151 |
| -8 | -22.2 | 22.2 | 22.7 | 153 | 157 |
| -7 | -21.7 | 23.0 | 23.5 | 158 | 162 |
| -6 | -21.1 | 23.8 | 24.3 | 164 | 168 |
| -5 | -20.6 | 24.6 | 25.1 | 170 | 173 |
| -4 | -20.0 | 25.4 | 26.0 | 175 | 179 |
| -3 | -19.4 | 26.3 | 26.8 | 181 | 185 |
| -2 | -18.9 | 27.1 | 27.7 | 187 | 191 |
| -1 | -18.3 | 28.0 | 28.6 | 193 | 197 |
| 0 | -17.8 | 28.9 | 29.5 | 199 | 203 |
| 1 | -17.2 | 29.8 | 30.4 | 206 | 210 |
| 2 | -16.7 | 30.7 | 31.3 | 212 | 216 |
| 3 | -16.1 | 31.7 | 32.3 | 218 | 222 |
| 4 | -15.6 | 32.6 | 33.2 | 225 | 229 |
| 5 | -15.0 | 33.6 | 34.2 | 231 | 236 |
| 6 | -14.4 | 34.5 | 35.2 | 238 | 242 |
| 7 | -13.9 | 35.5 | 36.2 | 245 | 249 |
| 8 | -13.3 | 36.5 | 37.2 | 252 | 256 |
| 9 | -12.8 | 37.6 | 38.2 | 259 | 263 |
| 10 | -12.2 | 38.6 | 39.3 | 266 | 271 |
| 11 | -11.7 | 39.6 | 40.3 | 273 | 278 |
| 12 | -11.1 | 40.7 | 41.4 | 281 | 285 |
| 13 | -10.6 | 41.8 | 42.5 | 288 | 293 |
| 14 | -10.0 | 42.9 | 43.6 | 296 | 300 |
| 15 | -9.4 | 44.0 | 44.7 | 304 | 308 |
| 16 | -8.9 | 45.1 | 45.8 | 311 | 316 |
| 17 | -8.3 | 46.3 | 47.0 | 319 | 324 |
| 18 | -7.8 | 47.5 | 48.2 | 327 | 332 |
| 19 | -7.2 | 48.6 | 49.4 | 335 | 340 |
| 20 | -6.7 | 49.8 | 50.6 | 344 | 349 |
| 21 | -6.1 | 51.1 | 51.8 | 352 | 357 |
| 22 | -5.6 | 52.3 | 53.0 | 361 | 366 |
| 23 | -5.0 | 53.5 | 54.3 | 369 | 374 |
| 24 | -4.4 | 54.8 | 55.6 | 378 | 383 |
| 25 | -3.9 | 56.1 | 56.9 | 387 | 392 |
| 26 | -3.3 | 57.4 | 58.2 | 396 | 401 |
| 27 | -2.8 | 58.7 | 59.5 | 405 | 410 |
| 28 | -2.2 | 60.1 | 60.8 | 414 | 419 |
| 29 | -1.7 | 61.4 | 62.2 | 423 | 429 |
| 30 | -1.1 | 62.8 | 63.6 | 433 | 438 |
| 31 | -0.6 | 64.2 | 65.0 | 443 | 448 |
| 32 | 0.0 | 65.6 | 66.4 | 452 | 458 |
| 33 | 0.6 | 67.0 | 67.9 | 462 | 468 |
| 34 | 1.1 | 68.5 | 69.3 | 472 | 478 |
| 35 | 1.7 | 70.0 | 70.8 | 482 | 488 |
| 36 | 2.2 | 71.5 | 72.3 | 493 | 498 |
| 37 | 2.8 | 73.0 | 73.8 | 503 | 509 |
| 38 | 3.3 | 74.5 | 75.3 | 514 | 520 |
| 39 | 3.9 | 76.0 | 76.9 | 524 | 530 |
| 40 | 4.4 | 77.6 | 78.5 | 535 | 541 |
| 41 | 5.0 | 79.2 | 80.1 | 546 | 552 |
| 42 | 5.6 | 80.8 | 81.7 | 557 | 563 |
| 43 | 6.1 | 82.5 | 83.3 | 568 | 575 |
| 44 | 6.7 | 84.1 | 85.0 | 580 | 586 |
| 45 | 7.2 | 85.8 | 86.7 | 591 | 598 |
| 46 | 7.8 | 87.5 | 88.4 | 603 | 609 |
| 47 | 8.3 | 89.2 | 90.1 | 615 | 621 |
| 48 | 8.9 | 90.9 | 91.9 | 627 | 633 |
| 49 | 9.4 | 92.7 | 93.6 | 639 | 645 |
| 50 | 10.0 | 94.5 | 95.4 | 651 | 658 |
| 51 | 10.6 | 96.3 | 97.2 | 664 | 670 |
| 52 | 11.1 | 98.1 | 99.1 | 676 | 683 |
| 53 | 11.7 | 100.0 | 101 | 689 | 696 |
| 54 | 12.2 | 102 | 103 | 702 | 709 |
| 55 | 12.8 | 104 | 105 | 715 | 722 |
| 56 | 13.3 | 106 | 107 | 728 | 735 |
| 57 | 13.9 | 108 | 109 | 742 | 748 |
| 58 | 14.4 | 110 | 111 | 755 | 762 |
| 59 | 15.0 | 112 | 113 | 769 | 776 |
| 60 | 15.6 | 114 | 115 | 783 | 790 |
| 61 | 16.1 | 116 | 117 | 797 | 804 |
| 62 | 16.7 | 118 | 119 | 811 | 818 |
| 63 | 17.2 | 120 | 121 | 825 | 832 |
| 64 | 17.8 | 122 | 123 | 840 | 847 |
| 65 | 18.3 | 124 | 125 | 854 | 862 |
| 66 | 18.9 | 126 | 127 | 869 | 877 |
| 67 | 19.4 | 128 | 129 | 884 | 892 |
| 68 | 20.0 | 130 | 132 | 899 | 907 |
| 69 | 20.6 | 133 | 134 | 915 | 922 |
| 70 | 21.1 | 135 | 136 | 930 | 938 |
| 71 | 21.7 | 137 | 138 | 946 | 954 |
| 72 | 22.2 | 140 | 141 | 962 | 970 |
| 73 | 22.8 | 142 | 143 | 978 | 986 |
| 74 | 23.3 | 144 | 145 | 994 | 1002 |
| 75 | 23.9 | 147 | 148 | 1011 | 1018 |
| 76 | 24.4 | 149 | 150 | 1027 | 1035 |
| 77 | 25.0 | 151 | 153 | 1044 | 1052 |
| 78 | 25.6 | 154 | 155 | 1061 | 1069 |
| 79 | 26.1 | 156 | 158 | 1078 | 1086 |
| 80 | 26.7 | 159 | 160 | 1096 | 1104 |
| 81 | 27.2 | 161 | 163 | 1113 | 1121 |
| 82 | 27.8 | 164 | 165 | 1131 | 1139 |
| 83 | 28.3 | 167 | 168 | 1149 | 1157 |
| 84 | 28.9 | 169 | 170 | 1167 | 1175 |
| 85 | 29.4 | 172 | 173 | 1185 | 1194 |
| 86 | 30.0 | 175 | 176 | 1204 | 1212 |
| 87 | 30.6 | 177 | 179 | 1223 | 1231 |
| 88 | 31.1 | 180 | 181 | 1241 | 1250 |
| 89 | 31.7 | 183 | 184 | 1261 | 1269 |
| 90 | 32.2 | 186 | 187 | 1280 | 1288 |
| 91 | 32.8 | 188 | 190 | 1299 | 1308 |
| 92 | 33.3 | 191 | 193 | 1319 | 1328 |
| 93 | 33.9 | 194 | 195 | 1339 | 1348 |
| 94 | 34.4 | 197 | 198 | 1359 | 1368 |
| 95 | 35.0 | 200 | 201 | 1380 | 1388 |
| 96 | 35.6 | 203 | 204 | 1400 | 1409 |
| 97 | 36.1 | 206 | 207 | 1421 | 1430 |
| 98 | 36.7 | 209 | 210 | 1442 | 1451 |
| 99 | 37.2 | 212 | 213 | 1463 | 1472 |
| 100 | 37.8 | 215 | 217 | 1484 | 1493 |
| 101 | 38.3 | 218 | 220 | 1506 | 1515 |
| 102 | 38.9 | 222 | 223 | 1528 | 1537 |
| 103 | 39.4 | 225 | 226 | 1550 | 1559 |
| 104 | 40.0 | 228 | 229 | 1572 | 1581 |
| 105 | 40.6 | 231 | 233 | 1595 | 1604 |
| 106 | 41.1 | 235 | 236 | 1617 | 1627 |
| 107 | 41.7 | 238 | 239 | 1640 | 1650 |
| 108 | 42.2 | 241 | 243 | 1664 | 1673 |
| 109 | 42.8 | 245 | 246 | 1687 | 1696 |
| 110 | 43.3 | 248 | 249 | 1711 | 1720 |
| 111 | 43.9 | 252 | 253 | 1734 | 1744 |
| 112 | 44.4 | 255 | 256 | 1759 | 1768 |
| 113 | 45.0 | 259 | 260 | 1783 | 1792 |
| 114 | 45.6 | 262 | 264 | 1808 | 1817 |
| 115 | 46.1 | 266 | 267 | 1832 | 1842 |
| 116 | 46.7 | 269 | 271 | 1857 | 1867 |
| 117 | 47.2 | 273 | 274 | 1883 | 1892 |
| 118 | 47.8 | 277 | 278 | 1908 | 1918 |
| 119 | 48.3 | 281 | 282 | 1934 | 1944 |
| 120 | 48.9 | 284 | 286 | 1960 | 1970 |
| 121 | 49.4 | 288 | 290 | 1986 | 1996 |
| 122 | 50.0 | 292 | 293 | 2013 | 2023 |
| 123 | 50.6 | 296 | 297 | 2040 | 2050 |
| 124 | 51.1 | 300 | 301 | 2067 | 2077 |
| 125 | 51.7 | 304 | 305 | 2094 | 2104 |
| 126 | 52.2 | 308 | 309 | 2122 | 2132 |
| 127 | 52.8 | 312 | 313 | 2150 | 2160 |
| 128 | 53.3 | 316 | 317 | 2178 | 2188 |
| 129 | 53.9 | 320 | 321 | 2206 | 2216 |
| 130 | 54.4 | 324 | 326 | 2235 | 2245 |
- Blend with glide: superheat uses the dew column, subcooling uses the bubble column.
- Simplified mixing model, within about 1 to 2 psi of the maker’s chart.
V = vacuum in inches of mercury. Saturation pressure in psig at sea level, calculated from reference equations of state. The chart gives the boiling temperature at that pressure, not the pipe temperature. Air in the system adds pressure and throws it off.
R-408A pressure in psig, psia, kPa and bar
| °F | °C | Dew psig | psia | kPa gauge | kPa absolute | bar absolute | Bubble psig |
|---|---|---|---|---|---|---|---|
| -60 | -51.1 | V 9.0 | 10.3 | -31 | 71 | 0.71 | V 8.5 |
| -55 | -48.3 | V 5.9 | 11.8 | -20 | 81 | 0.81 | V 5.4 |
| -50 | -45.6 | V 2.4 | 13.5 | -8 | 93 | 0.93 | V 1.8 |
| -45 | -42.8 | 0.7 | 15.4 | 5 | 106 | 1.06 | 1.0 |
| -40 | -40.0 | 2.8 | 17.5 | 19 | 121 | 1.21 | 3.2 |
| -35 | -37.2 | 5.2 | 19.8 | 36 | 137 | 1.37 | 5.5 |
| -30 | -34.4 | 7.7 | 22.4 | 53 | 154 | 1.54 | 8.1 |
| -25 | -31.7 | 10.5 | 25.2 | 73 | 174 | 1.74 | 10.9 |
| -20 | -28.9 | 13.6 | 28.3 | 94 | 195 | 1.95 | 14.1 |
| -15 | -26.1 | 17.0 | 31.7 | 117 | 218 | 2.18 | 17.4 |
| -10 | -23.3 | 20.6 | 35.3 | 142 | 243 | 2.43 | 21.1 |
| -5 | -20.6 | 24.6 | 39.3 | 170 | 271 | 2.71 | 25.1 |
| 0 | -17.8 | 28.9 | 43.6 | 199 | 301 | 3.01 | 29.5 |
| 5 | -15.0 | 33.6 | 48.3 | 231 | 333 | 3.33 | 34.2 |
| 10 | -12.2 | 38.6 | 53.3 | 266 | 367 | 3.67 | 39.3 |
| 15 | -9.4 | 44.0 | 58.7 | 304 | 405 | 4.05 | 44.7 |
| 20 | -6.7 | 49.8 | 64.5 | 344 | 445 | 4.45 | 50.6 |
| 25 | -3.9 | 56.1 | 70.8 | 387 | 488 | 4.88 | 56.9 |
| 30 | -1.1 | 62.8 | 77.5 | 433 | 534 | 5.34 | 63.6 |
| 35 | 1.7 | 70.0 | 84.7 | 482 | 584 | 5.84 | 70.8 |
| 40 | 4.4 | 77.6 | 92.3 | 535 | 636 | 6.36 | 78.5 |
| 45 | 7.2 | 85.8 | 100.5 | 591 | 693 | 6.93 | 86.7 |
| 50 | 10.0 | 94.5 | 109.2 | 651 | 753 | 7.53 | 95.4 |
| 55 | 12.8 | 104 | 118.4 | 715 | 816 | 8.16 | 105 |
| 60 | 15.6 | 114 | 128.2 | 783 | 884 | 8.84 | 115 |
| 65 | 18.3 | 124 | 138.6 | 854 | 956 | 9.56 | 125 |
| 70 | 21.1 | 135 | 149.6 | 930 | 1032 | 10.32 | 136 |
| 75 | 23.9 | 147 | 161.3 | 1011 | 1112 | 11.12 | 148 |
| 80 | 26.7 | 159 | 173.6 | 1096 | 1197 | 11.97 | 160 |
| 85 | 29.4 | 172 | 186.6 | 1185 | 1287 | 12.87 | 173 |
| 90 | 32.2 | 186 | 200.3 | 1280 | 1381 | 13.81 | 187 |
| 95 | 35.0 | 200 | 214.8 | 1380 | 1481 | 14.81 | 201 |
| 100 | 37.8 | 215 | 230.0 | 1484 | 1586 | 15.86 | 217 |
| 105 | 40.6 | 231 | 246.0 | 1595 | 1696 | 16.96 | 233 |
| 110 | 43.3 | 248 | 262.8 | 1711 | 1812 | 18.12 | 249 |
| 115 | 46.1 | 266 | 280.5 | 1832 | 1934 | 19.34 | 267 |
| 120 | 48.9 | 284 | 299.0 | 1960 | 2062 | 20.62 | 286 |
| 125 | 51.7 | 304 | 318.4 | 2094 | 2196 | 21.96 | 305 |
| 130 | 54.4 | 324 | 338.8 | 2235 | 2336 | 23.36 | 326 |
V = vacuum in inches of mercury. Absolute pressure = gauge + 14.7 psi at sea level; use absolute pressure for gas-law work. For blends the dew column is the vapour (suction) side and the bubble column the liquid side.
Other refrigerants
R-11 R-12 R-22 R-23 R-32 R-123 R-125 R-134a R-143a R-152a R-170 R-245fa R-290 R-401A R-401B R-404A R-407A R-407C R-407F R-409A R-410A R-417A R-422A R-422D R-427A R-448A R-449A R-450A R-452A R-452B R-454A R-454B R-454C R-455A R-500 R-502 R-507A R-508B R-513A R-600 R-600a R-717 R-744 R-1233zd(E) R-1234yf R-1234ze(E) R-1270
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Calculation aids and reference figures for licensed technicians. Always follow the manufacturer’s data plate and manual for the exact model, and local codes. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Pressures are typical saturation values and change with load and airflow.