R-454C PT Chart
A2L GWP 146Zeotropic blend (R-32/R-1234yf, 21.5/78.5%). HFO/HFC Blend.
About R-454C
R-454C is a low-GWP (146) A2L blend of R-32 and R-1234yf aimed at condensing units and small commercial refrigeration that has to meet GWP limits below 150. It runs lower pressure than R-404A and has a large glide of about 14°F, the biggest of any refrigerant on this site.
Saturation pressures at typical operating points, taken from the table below:
- Freezer evaporator (−20°F): 15.7 PSIG liquid / 6.8 PSIG vapor
- Medium-temp evaporator (20°F): 53.6 PSIG liquid / 36.7 PSIG vapor
- Condensing (105°F): 238.8 PSIG liquid / 196.9 PSIG vapor
The table covers -80°F to 165°F in 5°F steps. Below about -50°F the liquid saturation pressure is below atmospheric, so gauges read in vacuum (shown in blue in the table).
R-454C Pressure-Temperature Graph (Bubble & Dew)
R-454C Saturation Pressure Table
R-454C 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 | -8.5 | -10.8 | 6.2 | 43.0 | 0.43 |
| -75 | -59.4 | -7.4 | -10.1 | 7.3 | 50.0 | 0.5 |
| -70 | -56.7 | -6.3 | -9.3 | 8.4 | 58.2 | 0.58 |
| -65 | -53.9 | -5.0 | -8.4 | 9.7 | 67.2 | 0.67 |
| -60 | -51.1 | -3.5 | -7.3 | 11.2 | 77.4 | 0.77 |
| -55 | -48.3 | -1.8 | -6.1 | 12.9 | 88.8 | 0.89 |
| -50 | -45.6 | 0.0 | -4.8 | 14.7 | 101.3 | 1.01 |
| -45 | -42.8 | 2.0 | -3.4 | 16.7 | 115.4 | 1.15 |
| -40 | -40.0 | 4.3 | -1.7 | 19.0 | 131.0 | 1.31 |
| -35 | -37.2 | 6.8 | 0.1 | 21.5 | 148.2 | 1.48 |
| -30 | -34.4 | 9.5 | 2.2 | 24.2 | 166.8 | 1.67 |
| -25 | -31.7 | 12.4 | 4.3 | 27.1 | 186.8 | 1.87 |
| -20 | -28.9 | 15.7 | 6.8 | 30.4 | 209.6 | 2.1 |
| -15 | -26.1 | 19.2 | 9.5 | 33.9 | 233.7 | 2.34 |
| -10 | -23.3 | 23.0 | 12.5 | 37.7 | 259.9 | 2.6 |
| -5 | -20.6 | 27.3 | 15.8 | 42.0 | 289.6 | 2.9 |
| 0 | -17.8 | 31.8 | 19.3 | 46.5 | 320.6 | 3.21 |
| 5 | -15.0 | 36.6 | 23.1 | 51.3 | 353.7 | 3.54 |
| 10 | -12.2 | 41.9 | 27.3 | 56.6 | 390.2 | 3.9 |
| 15 | -9.4 | 47.5 | 31.8 | 62.2 | 428.8 | 4.29 |
| 20 | -6.7 | 53.6 | 36.7 | 68.3 | 470.9 | 4.71 |
| 25 | -3.9 | 60.1 | 42.0 | 74.8 | 515.7 | 5.16 |
| 30 | -1.1 | 67.0 | 47.6 | 81.7 | 563.3 | 5.63 |
| 35 | 1.7 | 74.4 | 53.7 | 89.1 | 614.3 | 6.14 |
| 40 | 4.4 | 82.3 | 60.3 | 97.0 | 668.8 | 6.69 |
| 45 | 7.2 | 90.8 | 67.4 | 105.5 | 727.4 | 7.27 |
| 50 | 10.0 | 99.7 | 74.8 | 114.4 | 788.7 | 7.89 |
| 55 | 12.8 | 109.2 | 82.9 | 123.9 | 854.2 | 8.54 |
| 60 | 15.6 | 119.2 | 91.4 | 133.9 | 923.2 | 9.23 |
| 65 | 18.3 | 129.9 | 100.5 | 144.6 | 997.0 | 9.97 |
| 70 | 21.1 | 141.2 | 110.3 | 155.9 | 1074.9 | 10.75 |
| 75 | 23.9 | 153.1 | 120.6 | 167.8 | 1156.9 | 11.57 |
| 80 | 26.7 | 165.6 | 131.5 | 180.3 | 1243.1 | 12.43 |
| 85 | 29.4 | 178.8 | 143.1 | 193.5 | 1334.1 | 13.34 |
| 90 | 32.2 | 192.7 | 155.5 | 207.4 | 1429.9 | 14.3 |
| 95 | 35.0 | 207.3 | 168.5 | 222.0 | 1530.6 | 15.31 |
| 100 | 37.8 | 222.7 | 182.4 | 237.4 | 1636.8 | 16.37 |
| 105 | 40.6 | 238.8 | 196.9 | 253.5 | 1747.8 | 17.48 |
| 110 | 43.3 | 255.6 | 212.3 | 270.3 | 1863.6 | 18.64 |
| 115 | 46.1 | 273.3 | 228.6 | 288.0 | 1985.7 | 19.86 |
| 120 | 48.9 | 291.7 | 245.7 | 306.4 | 2112.5 | 21.13 |
| 125 | 51.7 | 311.0 | 263.8 | 325.7 | 2245.6 | 22.46 |
| 130 | 54.4 | 331.1 | 282.9 | 345.8 | 2384.2 | 23.84 |
| 135 | 57.2 | 352.1 | 303.0 | 366.8 | 2529.0 | 25.29 |
| 140 | 60.0 | 373.9 | 324.1 | 388.6 | 2679.3 | 26.79 |
| 145 | 62.8 | 396.5 | 346.2 | 411.2 | 2835.1 | 28.35 |
| 150 | 65.6 | 420.1 | 369.7 | 434.8 | 2997.8 | 29.98 |
| 155 | 68.3 | 445.3 | 395.0 | 460.0 | 3171.6 | 31.72 |
| 160 | 71.1 | 471.0 | — | 485.7 | 3348.8 | 33.49 |
| 165 | 73.9 | 497.6 | — | 512.3 | 3532.2 | 35.32 |
Properties
| ASHRAE Designation | 454C |
| Safety Classification | A2L (mildly flammable) |
| GWP (AR4, 100-yr) | 146 |
| ODP | 0 |
| Molecular Weight | 90.8 g/mol |
| Boiling Point (1 atm) | -50.0°F / -45.6°C |
| Critical Temperature | 186.2°F / 85.7°C |
| Critical Pressure | 626.4 psia / 43.19 bar |
| Category | HFO/HFC Blend |
Common Applications
- New and retrofit commercial refrigeration (medium/low-temp condensing units, display cases)
- Low-GWP replacement for R-404A and R-22 in commercial refrigeration
- Light commercial AC and chiller applications in some regions
Frequently Asked Questions
What is the pressure of R-454C at 70°F?
At 70°F, R-454C runs about 141.2 PSIG on the liquid (bubble point) side. Because R-454C has significant temperature glide (due to its high R-1234yf content), the vapor side can read noticeably lower at the same nominal temperature — always check whether a gauge reading corresponds to the liquid or vapor line before diagnosing charge.
How does R-454C compare to R-454B?
R-454C carries far less R-32 (21.5% vs. R-454B's roughly 68.9%) and much more R-1234yf, so its operating pressures run noticeably lower — roughly 25-30% below R-454B at the same temperature — and its GWP is lower too (146 vs. about 467 for R-454B). R-454C is typically positioned as a lower-pressure R-404A/R-22 replacement in commercial refrigeration rather than a direct R-410A-family substitute the way R-454B is.
Is R-454C flammable, and what handling precautions apply?
Yes — R-454C is ASHRAE-classified A2L, meaning it is mildly flammable with a low burning velocity, unlike nonflammable legacy refrigerants such as R-404A or R-22. Technicians should use A2L-listed recovery machines, gauges, and leak detectors, ensure adequate ventilation, avoid ignition sources near a system in service, and follow the manufacturer's A2L-specific installation and charge-limit requirements.