R-404A Pressure at -25°F — Saturation P-T Data
How This Was Calculated
Saturation pressure interpolated from ASHRAE tabular data for R404A. Very low pressure — low temperature suction conditions.
- P_sat
- Saturation pressure: 19 PSI
- T_input
- Input temperature: -25°F
- T_data
- ASHRAE tabular reference data: R404A
Important Considerations
R-404A has a very high GWP (3,922) and is a priority phase-down target under the AIM Act. EPA regulations restrict its use in new refrigeration equipment. Replacements include R-448A, R-449A, and R-744 (CO2) transcritical systems for commercial refrigeration.
-25°F is a very low operating temperature. At these suction conditions, R404A refrigeration systems face reduced compressor efficiency due to low suction pressure and high compression ratios. Crankcase heaters are critical to prevent refrigerant migration into oil. Head pressure control (fan cycling or fan speed control) is needed to maintain minimum condensing pressure. For heat pump operation, defrost cycles become more frequent below 20°F.
The saturation pressure shown (for R404A at -25°F) is the baseline for measuring superheat and subcooling. Suction superheat = suction line temperature minus evaporator saturation temperature. Subcooling = condensing saturation temperature minus liquid line temperature. Typical targets: 8–12°F superheat at the evaporator (TXV systems), 10–20°F subcooling at the condenser. Deviations indicate improper charge, metering device issues, or non-condensables.
R404A — consult ASHRAE Standard 34 and manufacturer safety data sheet for handling requirements. EPA Section 608 certification is required for purchase and handling.
R404A has a GWP of 3,922 — meaning 1 lb released equals 3,922 lbs of CO2 equivalent warming over 100 years. This places it in the high-GWP category subject to accelerated phase-down under the AIM Act (American Innovation and Manufacturing Act). EPA regulations are reducing HFC production and import allowances through 2036. Lower-GWP alternatives are available: R-32 (GWP 675), R-454B (GWP 466), and R-290 (GWP 3) depending on application.
Saturation pressure-temperature data for R404A derived from ASHRAE Fundamentals Handbook, Chapter 30 (Thermophysical Properties of Refrigerants), and verified against manufacturer published data (Chemours Opteon, Honeywell Solstice). Values represent saturated conditions at sea level.