R-448A PT Chart
A1 GWP 1387Zeotropic blend (R-32/R-125/R-1234yf/R-1234ze(E)/R-134a, 26.0/26.0/20.0/21.0/7.0%). HFO/HFC Blend.
About R-448A
R-448A (Solstice N40) is one of the two main lower-GWP replacements for R-404A in supermarkets and walk-ins. Its liquid pressure tracks R-404A closely, but it has about 10°F of glide, so its vapor (dew) pressure is much lower than its liquid pressure. Techs used to R-404A often misjudge superheat until they switch to the dew column.
Saturation pressures at typical operating points, taken from the table below:
- Freezer evaporator (−20°F): 16.9 PSIG liquid / 9.4 PSIG vapor
- Medium-temp evaporator (20°F): 57.3 PSIG liquid / 43.5 PSIG vapor
- Condensing (105°F): 260.3 PSIG liquid / 227.9 PSIG vapor
The table covers -80°F to 175°F in 5°F steps. Below about -51°F the liquid saturation pressure is below atmospheric, so gauges read in vacuum (shown in blue in the table).
R-448A Pressure-Temperature Graph (Bubble & Dew)
R-448A Saturation Pressure Table
R-448A 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 | -8.3 | -10.4 | 6.4 | 44.1 | 0.441 |
| -75 | -59.4 | -7.2 | -9.6 | 7.46 | 51.4 | 0.514 |
| -70 | -56.7 | -6.0 | -8.7 | 8.66 | 59.7 | 0.597 |
| -65 | -53.9 | -4.7 | -7.7 | 10.02 | 69.1 | 0.691 |
| -60 | -51.1 | -3.2 | -6.6 | 11.54 | 79.6 | 0.796 |
| -55 | -48.3 | -1.4 | -5.2 | 13.25 | 91.4 | 0.914 |
| -50 | -45.6 | 0.4 | -3.8 | 15.14 | 104.4 | 1.044 |
| -45 | -42.8 | 2.6 | -2.1 | 17.25 | 118.9 | 1.189 |
| -40 | -40.0 | 4.9 | -0.3 | 19.59 | 135.1 | 1.351 |
| -35 | -37.2 | 7.5 | 1.8 | 22.17 | 152.9 | 1.529 |
| -30 | -34.4 | 10.3 | 4.1 | 25.02 | 172.5 | 1.725 |
| -25 | -31.7 | 13.4 | 6.6 | 28.14 | 194.0 | 1.94 |
| -20 | -28.9 | 16.9 | 9.4 | 31.56 | 217.6 | 2.176 |
| -15 | -26.1 | 20.6 | 12.4 | 35.3 | 243.4 | 2.434 |
| -10 | -23.3 | 24.7 | 15.8 | 39.37 | 271.4 | 2.714 |
| -5 | -20.6 | 29.1 | 19.5 | 43.8 | 302.0 | 3.02 |
| 0 | -17.8 | 33.9 | 23.5 | 48.61 | 335.2 | 3.352 |
| 5 | -15.0 | 39.1 | 27.9 | 53.82 | 371.1 | 3.711 |
| 10 | -12.2 | 44.7 | 32.7 | 59.44 | 409.8 | 4.098 |
| 15 | -9.4 | 50.8 | 37.9 | 65.5 | 451.6 | 4.516 |
| 20 | -6.7 | 57.3 | 43.5 | 72.02 | 496.6 | 4.966 |
| 25 | -3.9 | 64.3 | 49.5 | 79.03 | 544.9 | 5.449 |
| 30 | -1.1 | 71.8 | 56.0 | 86.54 | 596.7 | 5.967 |
| 35 | 1.7 | 79.9 | 63.0 | 94.57 | 652.0 | 6.52 |
| 40 | 4.4 | 88.5 | 70.6 | 103.16 | 711.3 | 7.113 |
| 45 | 7.2 | 97.6 | 78.7 | 112.32 | 774.4 | 7.744 |
| 50 | 10.0 | 107.4 | 87.3 | 122.07 | 841.6 | 8.416 |
| 55 | 12.8 | 117.7 | 96.6 | 132.43 | 913.1 | 9.131 |
| 60 | 15.6 | 128.7 | 106.5 | 143.44 | 989.0 | 9.89 |
| 65 | 18.3 | 140.4 | 117.0 | 155.11 | 1069.4 | 10.694 |
| 70 | 21.1 | 152.8 | 128.2 | 167.46 | 1154.6 | 11.546 |
| 75 | 23.9 | 165.8 | 140.1 | 180.52 | 1244.6 | 12.446 |
| 80 | 26.7 | 179.6 | 152.7 | 194.31 | 1339.7 | 13.397 |
| 85 | 29.4 | 194.2 | 166.1 | 208.85 | 1440.0 | 14.4 |
| 90 | 32.2 | 209.5 | 180.3 | 224.17 | 1545.6 | 15.456 |
| 95 | 35.0 | 225.6 | 195.3 | 240.28 | 1656.7 | 16.567 |
| 100 | 37.8 | 242.5 | 211.2 | 257.2 | 1773.3 | 17.733 |
| 105 | 40.6 | 260.3 | 227.9 | 274.97 | 1895.9 | 18.959 |
| 110 | 43.3 | 278.9 | 245.6 | 293.6 | 2024.3 | 20.243 |
| 115 | 46.1 | 298.4 | 264.2 | 313.11 | 2158.8 | 21.588 |
| 120 | 48.9 | 318.8 | 283.8 | 333.52 | 2299.5 | 22.995 |
| 125 | 51.7 | 340.2 | 304.5 | 354.85 | 2446.6 | 24.466 |
| 130 | 54.4 | 362.4 | 326.2 | 377.13 | 2600.2 | 26.002 |
| 135 | 57.2 | 385.7 | 349.0 | 400.37 | 2760.5 | 27.605 |
| 140 | 60.0 | 409.9 | 373.0 | 424.59 | 2927.4 | 29.274 |
| 145 | 62.8 | 435.1 | 398.3 | 449.82 | 3101.4 | 31.014 |
| 150 | 65.6 | 461.4 | 425.6 | 476.06 | 3282.3 | 32.823 |
| 155 | 68.3 | 488.6 | 452.9 | 503.34 | 3470.4 | 34.704 |
| 160 | 71.1 | 517.0 | — | 531.68 | 3665.8 | 36.658 |
| 165 | 73.9 | 546.4 | — | 561.1 | 3868.6 | 38.686 |
| 170 | 76.7 | 576.9 | — | 591.6 | 4078.9 | 40.789 |
| 175 | 79.4 | 608.5 | — | 623.22 | 4297.0 | 42.97 |
Properties
| ASHRAE Designation | 448A |
| Safety Classification | A1 (non-flammable, low toxicity) |
| GWP (AR4, 100-yr) | 1387 |
| ODP | 0 |
| Molecular Weight | 86.3 g/mol |
| Boiling Point (1 atm) | -50.6°F / -45.9°C |
| Critical Temperature | 180.8°F / 82.7°C |
| Critical Pressure | 666.4 psia / 45.95 bar |
| Category | HFO/HFC Blend |
Common Applications
- Supermarket refrigeration racks (retrofit and new installs replacing R-404A/R-507A)
- Walk-in coolers and freezers, and reach-in display cases
- Cold storage warehouses and self-contained condensing units
Frequently Asked Questions
Is R-448A a drop-in replacement for R-404A?
R-448A (Solstice N40) is a near-drop-in replacement for R-404A and R-507A, designed to work in most existing DX refrigeration systems with only minor changes (POE oil check, elastomer/seal compatibility, and typically a TXV adjustment). Because it is a zeotropic blend with roughly 10-11°F of temperature glide, it should always be charged into the system as a liquid, not vapor, to avoid fractionation.
What is the saturation pressure of R-448A at 70°F?
At 70°F (21.1°C), R-448A's saturated liquid-line pressure runs about 152.8 PSIG (167.5 PSIA). Because of the blend's glide, the vapor (dew-point) side reads somewhat lower at the same nominal temperature, which is normal and expected for zeotropic blends.
What brand name is R-448A sold under?
R-448A is marketed almost exclusively as Honeywell's Solstice N40, its original developer and primary trade-name holder. It's used mainly as a lower-GWP replacement for R-404A and R-507A in supermarket refrigeration racks, walk-in coolers/freezers, and cold storage.