R-407C Pressure at -20°F — Saturation P-T Data
How This Was Calculated
Saturation pressure interpolated from ASHRAE tabular data for R407C. Very low pressure — low temperature suction conditions.
- P_sat
- Saturation pressure: 14 PSI
- T_input
- Input temperature: -20°F
- T_data
- ASHRAE tabular reference data: R407C
Important Considerations
-20°F is a very low operating temperature. At these suction conditions, R407C 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 R407C at -20°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.
R407C — consult ASHRAE Standard 34 and manufacturer safety data sheet for handling requirements. EPA Section 608 certification is required for purchase and handling.
R407C has a GWP of 1,774 — meaning 1 lb released equals 1,774 lbs of CO2 equivalent warming over 100 years. It falls under AIM Act HFC phase-down regulations but is considered a transitional refrigerant with lower impact than legacy options like R-22 or R-404A. Lower-GWP alternatives (R-32 at GWP 675, R-454B at GWP 466) are increasingly available for new equipment.
Saturation pressure-temperature data for R407C 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.