Heating, Ventilation and Air Conditioning
Refrigerant Circuit with Expansion Valve
In this manual: Heating, Ventilation and Air Conditioning
3steps
~18min
2/5difficulty
Done 0 of 3
A-Low pressure side of refrigerant circuit.
B-High pressure side of refrigerant circuit.

| Component | Aggregate State of Refrigerant | Pressure bar (psi) Positive Pressure | Temperature in Degrees Celsius (Fahrenheit) |
| -1- Evaporator, from input to output | Vapor | Approximately 1.2 (17.4) → Note | Approximately -7 (20) → Note |
| (Approximately 1.8 (26.1)) → Note | Approximately -1 (30) → Note | ||
| -2- A/C compressor A-side | Gas | Approximately 1.2 (17.4) → Note | Approximately -1 (30) |
| (Approximately 1.8 (26.1)) → Note | Approximately -1 (30) → Note | ||
| -3- A/C compressor B-side | Gas | Approximately 14 (203.1) | Approximately 65 (149) |
| -4- Condenser | Gas, vapor, fluid | Approximately 14 (203.1) | Approximately 55 (131) at outlet |
| -5- Receiver | Fluid | Approximately 14 (203.1) | Approximately 55 (131) |
| -6- Extraction and filling valve, B-side | Fluid | Approximately 14 (203.1) | Approximately 55 (131) |
| -7- Expansion valve | Fluid, released as vapor | Approximately 14 (203.1) | Approximately 55 (131), reduced to -7 (20) |
| -8- Extraction and filling valve, A-side | Gas | Approximately 1.2 (17.4) → Note | Approximately -7 (20) → Note |
| (Approximately 1.8 (26.1)) → Note | Approximately -1 (30) → Note |
- Pressure in refrigerant circuits is maintained at approximately 2 bar (29 psi), regulated by A/C compressor, even though heat transfer changes and engine speeds vary. However, this applies only within the performance range of the A/C compressor; if the performance limits of the A/C compressor are exceeded, the pressure increases. Refer to → Chapter "Pressures, Checking".
- Within the control range of the A/C compressor, temperature in the refrigerant circuits is maintained, regulated by A/C compressor, even though heat transfer changes and engine speeds vary. However, this applies only within the performance range of the A/C compressor; if the performance limits of the A/C compressor are exceeded, the temperature increases. Refer to → Chapter "Pressures, Checking".
- Measured values for A/C systems with two evaporators
Note A/C compressors which do not regulate their performance are switched off by the respective control module via the A/C Compressor Regulator Valve -N280- at an evaporator temperature below 0 C (32 F). In vehicles with A/C Compressor Regulator Valve -N280-, the pressure is modified on the low pressure side by the valve. |
Test yourself
A quick Volkswagen Touran quiz: every answer comes with an explanation and a link to the manual page.
Was this page helpful?
Note A/C compressors which do not regulate their performance are switched off by the respective control module via the A/C Compressor Regulator Valve -N280- at an evaporator temperature below 0 C (32 F). In vehicles with A/C Compressor Regulator Valve -N280-, the pressure is modified on the low pressure side by the valve.