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Home >> Audi >> 2021 >> A4 Quattro Premium Plus, 2.0L Eng VIN B >> Repair and Diagnosis >> Heating, Ventilation & A/C (HVAC) >> A/C Compressor >> Air Conditioning (Refrigerant R1234YF Servicing) (2 Of 2) >> 87 Air Conditioning >> Refrigerant Circuit >> Refrigerant Circuit, Cleaning >> Connection Diagram For Cleaning (Flushing), Refrigerant Circuit With Expansion Valve And Receiver/Dryer

Connection Diagram For Cleaning (Flushing), Refrigerant Circuit With Expansion Valve And Receiver/Dryer

NOTE:

The arrows in the following illustrations show the refrigerant flow direction during flushing (refrigerant flows in opposite direction of flow when A/C system is in operation while flushing, therefore the high pressure side of the A/C Service System is connected to the low pressure connection of the refrigerant circuit to the A/C compressor).

This main wiring diagram shows a refrigerant circuit with expansion valve, receiver/dryer and second evaporator (optional equipment on certain vehicles).

On vehicles with an expansion valve and receiver/dryer, the expansion valve is removed and replaced by an adapter. Depending on the vehicle, the receiver/dryer must also be removed and line connections to fluid reservoir be connected to each other by two adapters and a charge hose.

On a vehicle with only one evaporator, components from item "16" are not present or are not needed.

Depending on the construction of the A/C Service Station, check valves may be installed between the refrigerant circuit and the A/C Service Station (to guarantee the correct direction of refrigerant flow during flushing).

The adapter from the VW/Audi - Passenger Vehicle Adapter Set are provided with 5/8" -18 UNF threads use additional adapters from the VW/Audi - Passenger Vehicle Adapter Set so that the R1234yf -A/C Service Station filling hose can be attached. Refer to the Parts Information.

On vehicles with a high-voltage system power-operated valves are installed in the refrigerant circuit, which must be removed to clean (flush) and replaced with hand shut-off valves or adapters. Refer to Refrigerant Circuit .

Fig 1: Block Diagram For Flushing Circuits (Type 1)
GWWA87-10131Courtesy of AUDI OF AMERICA, LLC
  1. A/C Service Station
    • With electronics and a flushing program, A/C Service Station with flushing device. Refer to the Parts Information (Tools; Special Tools and Equipment: A/C and Heating).
    • If an A/C Service Station without a flushing program is used, the procedure must be performed manually (evacuate, flush four times with at least 3 kg refrigerant for each and extract the refrigerant again, evacuate).
  2. Refrigerant Hose for A/C Service Station
    • From the high pressure side of the A/C Service Station (mostly red colored) to the low pressure side connection of the A/C compressor on refrigerant circuit (larger diameter).
  3. Adapter to Connection for Low Pressure Side on Refrigerant Circuit
    • There are different versions depending on vehicle. Refer to ADAPTER FOR ASSEMBLING FLUSHING CIRCUIT .
    • Use the Refrigerant Circuits Adapter Set - Adapter 48 :VAS6338/48  between the refrigerant hose -2- and the adapter -3-.
    • From the VW/Audi - Passenger Vehicle Adapter Set.
    • Depending on the version of the adapter an additional adapter is necessary to connect the A/C Service Station filling hose.
      NOTE:

      The A/C Service Station filler hose has a M12 x 1.5-6G external thread according to SAE J639 on the adapter to the connection for the low pressure side an 5/8 -18 UNF external thread is available. An additional adapter is necessary so that both components can be connected. Refer to the Parts Information (Tools; Special Tools and Equipment: A/C and Heating).

      To reach a maximum possible flow speed, the service coupling is removed from the filler hose to flush (there are constrictions in the service coupling, which significantly reduces the flow speed velocity).

  4. Low Pressure Side Connection on Refrigerant Circuit
  5. Adapter for Removed Expansion Valve
    • There are different versions depending on vehicle. Refer to ADAPTER FOR ASSEMBLING FLUSHING CIRCUIT .
    • From the VW/Audi - Passenger Vehicle Adapter Set. Refer to the Parts Information (Tools; Special Tools and Equipment: A/C and Heating).
  6. Evaporator
  7. Connection to Receiver/Dryer
  8. Adapter for Bridging Removed Receiver/Dryer
  9. Refrigerant Filler Hose
  10. Condenser
    • If the receiver/dryer is attached directly to the condenser, the receiver/dryer must be removed and replaced only after flushing. Refer to Refrigerant Circuit .
    • If a receiver/dryer with dryer cartridge is installed on the condenser, the dryer cartridge must be removed (reseal the receiver/dryer at or in the condenser after removing). Refer to Refrigerant Circuit .
      NOTE:

      On certain vehicles the receiver/dryer is integrated inside the condenser and the dryer cartridge cannot be replaced separately and is not available as a single part. In this case, replace the condenser with the receiver/dryer / dryer cartridge after flushing on these vehicles. Refer to Refrigerant Circuit and the Parts Information.

  11. High Pressure Side Connection on Refrigerant Circuit
  12. Adapter to Connection for High Pressure Side on Refrigerant Circuit
  13. Charging Hose for Refrigerant Circuit Flushing Device
    • From the connection to the high pressure side of the A/C compressor on the refrigerant circuit (smaller diameter) to the input of the refrigerant circuit flushing device.
  14. Refrigerant Circuit Flushing Device
    • There are different versions of the Refrigerant Circuit Flushing Device. Refer to the Parts Information (Tools; Special Tools and Equipment: A/C and Heating).
    • With filter, viewing glass, safety valve, heater, refrigerant reservoir, etc. (depending on version).
    • Depending on the construction of the A/C Service Station and of refrigerant circuit flushing device, a check valve may be installed at the output of the refrigerant circuit flushing device (to guarantee correct direction of refrigerant flow during flushing).
    • Depending on the flushing device a 5/8 -18 UNF external thread a connection for a R134a or a R1234yf high pressure service coupling can be present on the output for the A/C Service Station.
      NOTE:

      So that the flushing device can be connected on the A/C Service Station on flushing devices with a 5/8 -18 UNF external thread or a connection for a R134a low pressure side service connection an additional adapter is necessary to connect the R1234yf low pressure side service connection or a filler hose to the A/C Service Station (with a M12 x 1.5-6G external thread according to SAE J639) to the output of the flushing device.

      The filler hose from the A/C Service Station has a M12 x 1.5-6G external thread according to SAE J639. On the flushing device for the refrigerant circuit there can be a service connection for a low pressure side service connection according to SAE J639 for the refrigerant R1234yf, a M12 x 1.5-6G inner thread according to SAE J639, a service connection for a R134a low pressure side service connection or a 5/8 -18 UNF external thread depending on the version. So that both components can be connected an additional adapter may be necessary. Refer to the Parts Information.

      So that the refrigerant with a lower flow speed can be extracted by the A/C Service Station the low pressure side service connection can be used here.

  15. Refrigerant Hose for A/C Service Station
    • From the low pressure side of the A/C Service Station (mostly blue colored) to the output of the refrigerant circuit flushing device.
  16. Adapter for Sealing Outlet to Second Evaporator
    • Only necessary on certain vehicles with optional equipment "second evaporator"
    • From the VW/Audi - Passenger Vehicle Adapter Set.
  17. Adapter for Sealing Outlet to Second Evaporator
    • Only necessary on certain vehicles with optional equipment "second evaporator"
    • From the VW/Audi - Passenger Vehicle Adapter Set.
  18. Low Pressure Side Connection on Refrigerant Circuit to Second Evaporator
  19. High Pressure Side Connection on Refrigerant Circuit to Second Evaporator
  20. Adapter for Removed Expansion Valve on Second Evaporator
    • There are different versions depending on the vehicle. Refer to ADAPTER FOR ASSEMBLING FLUSHING CIRCUIT .
    • Only necessary on certain vehicles with optional equipment "second evaporator"
    • From the VW/Audi - Passenger Vehicle Adapter Set.
  21. Second Evaporator
    • Only present on certain vehicles with optional equipment "second evaporator"
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