General information for pressure and temperature in the refrigerant circuit

The pressures and temperatures in the refrigerant circuit depend on the current operating conditions (such as engine speed, radiator fan level 1, 2 or 3, engine temperature, A/C compressor activation on or off) as well as on the effects of outside influences (such as outside temperature, humidity, desired cooling output).
In vehicles with A/C Compressor Regulator Valve -N280-, the pressure is modified on the low pressure side by the A/C Compressor Regulator Valve -N280-.
For this reason, values indicated in the following table are valid only as reference points. They are attained at an engine speed of 1500 to 2000 RPM and an ambient temperature of 20 °C (68 °F) after approximately 20 minutes.
The pressure gauge set connections intended for the pressure measurement can be found in the vehicle-specific refrigerant circuit. Refer to Refrigerant Circuit .
At 20 °C (68 °F) with the engine not running, the pressure in the refrigerant circuit is 4.7 bar (68.17 psi). Refer to REFRIGERANT VAPOR PRESSURE TABLE (vapor pressure table).

NOTE:

Pressure is measured in different units: 1 MPa (mega Pascal) corresponds to 10 bar (145 psi) positive pressure. 1 bar (1.45 psi) absolute pressure corresponds to 0 bar (0 psi) positive pressure and thus to the ambient pressure (atmospheric pressure).

The pressure and temperature is approximately the same on refrigerant circuits restrictor and reservoir as in refrigerant circuits with expansion valve. Because currently for Volkswagen/Audi only refrigerant circuits with expansion valves are installed, only this refrigerant circuit is described here.