Pressure-Temperature Relationship of R-134a
Evaporator Range: From -7 to 7°C (19.4 to 44.6°F), the temperatures represent the gas temperatures inside the coil and not on the coil surfaces. Add 2 to 6°C (36 to 43°F) to the coil and air-off temperatures.
Condenser Range: From 45 to 70°C (113 to 158°F), the temperatures are not ambient. Add 19 to 22°C (66 to 72°C) to the ambient temperatures for proper heat transfer. Then refer to the pressure chart.
Example:
32°C (90°F) Ambient temperature + 22°C (40°F) = 54°C (130°F)
Condenser temperature, which yields 1,379 kPa (200 psi), based on 50 km/h (31 mph) airflow.