System Overview - Refrigerant Circuit

HD = High Pressure Side

ND = Low Pressure Side

Courtesy of AUDI OF AMERICA, LLC

1. A/C Compressor Regulator Valve -N280-
   • To check the activation and function, use the Vehicle Diagnostic Tester in the"Guided Fault Finding"  function. Refer to A/C Compressor Regulator Valve -N280-, CHECKING SWITCH-ON SIGNAL  and the appropriate Wiring Diagram.
     NOTE:

     Certain malfunctions at the A/C Compressor Regulator Valve -N280- (for example, a stuck valve or a short circuit in the coil) can lead to a complaint regarding the A/C compressor (A/C system is not cooling, the evaporator ices over, etc.). If the A/C Compressor Regulator Valve -N280- (and not the A/C compressor itself) is the cause, the A/C compressor can be serviced by replacing the A/C Compressor Regulator Valve -N280-. Refer to Refrigerant Circuit Components, Replacing or COMPONENTS, REPLACING .

     The A/C Compressor Regulator Valve -N280- is not available as a replacement part for all A/C compressors. If the A/C Compressor Regulator Valve -N280- is not available as an individual A/C compressor part (different versions), then the entire A/C compressor must be replaced if there is a complaint. Refer to the Parts Information.

2. A/C Compressor
   • There are different versions depending on the refrigerant (R134a or R1234yf). Refer to Parts Information.
   • Overview. Refer to OVERVIEW - A/C COMPRESSOR POWER UNIT .
     NOTE:

     An additional weight (balance weight, resonator in the refrigerant line to reduce noise) may be present on the refrigerant line on the low pressure side depending on the refrigerant line version and the production period. Refer to ADDITIONAL WEIGHT ON REFRIGERANT LINE . Make sure that this component is not touching or can come in contact with other components during operation (noise). Refer to the Parts Information.

3. Pressure Relief Valve
   CAUTION:

   Danger due to refrigerant coming out under pressure when there is a faulty valve.

   Danger of frost bite to skin and other parts of the body.

   • Only remove when the refrigerant circuit is empty. The connection does not have a valve.
4. Closure Cap
   • With seal
   • Always screw on
   • There are different versions depending on the refrigerant (R134a or R1234yf). Refer to SERVICE CONNECTION DIFFERENCES, DEPENDING ON REFRIGERANT (R134A OR R1234YF)  or Parts Information.
5. Low Pressure Side Service Connection
   • For measuring and discharging
     CAUTION:

     Danger due to refrigerant coming out under pressure when there is a faulty valve in the refrigerant circuit.

     Danger of frost bite to skin and other parts of the body.

     • Only remove when the refrigerant circuit is empty; the connection is without a valve. Refer to A/C SYSTEM, GENERAL INFORMATION or GENERAL DESCRIPTION - REFRIGERANT CIRCUIT COMPONENTS .
   • There are different versions depending on the refrigerant (R134a or R1234yf). Refer to SERVICE CONNECTION DIFFERENCES, DEPENDING ON REFRIGERANT (R134A OR R1234YF)  or Parts Information.
6. Connection in Refrigerant Line - Low Pressure Side
   • To the A/C compressor
7. Connection in Refrigerant Line - Low Pressure Side
   • From the expansion valve
8. Expansion Valve
   • Overview. Refer to OVERVIEW - CONDENSER, A/C COMPRESSOR, REFRIGERANT LINES AND EXPANSION VALVE .
   • There are different versions depending on the refrigerant (R134a or R1234yf). Refer to SERVICE CONNECTION DIFFERENCES, DEPENDING ON REFRIGERANT (R134A OR R1234YF)  or Parts Information.
9. Evaporator
   • Overview. Refer to OVERVIEW - CONDENSER, A/C COMPRESSOR, REFRIGERANT LINES AND EXPANSION VALVE .
10. Connection in Refrigerant Line - High Pressure Side
    • To the expansion valve
11. Refrigerant Line with Inner Heat Exchanger
    • In the inner heat exchanger, warm liquid refrigerant flowing on the high pressure side delivers energy to the cold vaporous refrigerant flowing on the low pressure side. This increases the efficiency of the A/C system.
    • Removing and Installing. Refer to REFRIGERANT LINES WITH INNER HEAT EXCHANGER, REMOVING AND INSTALLING .
12. Connection in Refrigerant Line - High Pressure Side
    • From the condenser
13. Refrigerant Circuit Pressure Sensor -G805-
    • To check, use the Vehicle Diagnostic Tester in the"Guided Fault Finding"  function. Refer to the appropriate Wiring Diagram.
    • Removing and Installing. Refer to Refrigerant Circuit Pressure Sensor -G805-, REMOVING AND INSTALLING .
14. Connection with Valve
15. Condenser
    • Overview. Refer to OVERVIEW - CONDENSER, A/C COMPRESSOR, REFRIGERANT LINES AND EXPANSION VALVE .
16. Dryer Cartridge
    • Overview. Refer to OVERVIEW - CONDENSER, A/C COMPRESSOR, REFRIGERANT LINES AND EXPANSION VALVE .
17. High Pressure Side Service Connection
    • For measuring, discharging and charging
      CAUTION:

      Danger due to refrigerant coming out under pressure when there is a faulty valve in the refrigerant circuit.

      Danger of frost bite to skin and other parts of the body.

      • Only remove when the refrigerant circuit is empty; the connection is without a valve. Refer to A/C SYSTEM, GENERAL INFORMATION or GENERAL DESCRIPTION - REFRIGERANT CIRCUIT COMPONENTS .
    • There are different versions depending on the refrigerant (R134a or R1234yf). Refer to SERVICE CONNECTION DIFFERENCES, DEPENDING ON REFRIGERANT (R134A OR R1234YF)  or Parts Information.
18. Closure Cap
    • With seal
    • Always screw on
    • There are different versions depending on the refrigerant (R134a or R1234yf). Refer to SERVICE CONNECTION DIFFERENCES, DEPENDING ON REFRIGERANT (R134A OR R1234YF)  or Parts Information.