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Heating and Air Conditioning



Flushing Circuit Block Diagrams

NOTE:
- The arrows in the following illustrations show the direction of refrigerant flow while flushing. During flushing, refrigerant flows in the opposite direction than during A/C system operation, therefore the high pressure side of A/C service station is connected to A/C compressor at low pressure side of refrigerant circuit.
- These block diagrams show a refrigerant circuit with restrictor and reservoir and a refrigerant circuit with expansion valve, fluid reservoir and a second evaporator (optional equipment on certain vehicles).
- Depending on the design of A/C service station, check-valves may be installed between refrigerant circuit and A/C service station. They guarantee the correct direction of refrigerant flow during flushing.

Refrigerant Circuit with Restrictor and Reservoir

NOTE: On vehicles with restrictor and reservoir, the restrictor and reservoir are removed. Restrictor refrigerant pipes are reassembled. Refrigerant pipes to the removed reservoir are connected with each other via two adapters and charge hose VAS 6338/31 (from VW/Audi passenger vehicle set adapter chest VAS 6338/1).







1 - A/C service station
- With electronics and a flushing program, e.g. A/C service station with flushing device VAS 6380 or A/C service station with flushing device VAS 6337.
- If an A/C service station without a flushing program is used, the procedure must be performed manually (evacuate, flush 3 times with at least 4 kg refrigerant each and extract refrigerant again, evacuate).
2 - Refrigerant hose of A/C service station
- From high pressure side of A/C service station (mostly colored red) to low pressure side connection of A/C compressor on refrigerant circuit (larger diameter).
3 - Adapter to connection for low pressure side on refrigerant circuit
- Different versions depending on vehicle.
- From VW/Audi passenger vehicle set adapter chest VAS 6338/1.
4 - Low pressure side connection on refrigerant circuit
- Different versions depending on vehicle.
- On refrigerant line from A/C compressor to reservoir.
5 - Connection to reservoir
- Different versions depending on vehicle.
- On refrigerant line from A/C compressor to reservoir.
6 - Adapter for bridging the removed reservoir
- Different versions depending on vehicle.
- From VW/Audi passenger vehicle set adapter chest VAS 6338/1.
7 - Refrigerant charge hose.
- Charge hose VAS 6338/31 (from VW/Audi passenger vehicle set adapter chest VAS 6338/1 ) for example.
8 - Adapter for bridging the removed reservoir.
- Different versions depending on vehicle.
- From VW/Audi passenger vehicle set adapter chest VAS 6338/1.
9 - Connection to reservoir
- Different versions depending on vehicle.
10 - Evaporator
11 - Component location of restrictor
- Restrictor is removed.
- Remove restrictor.
12 - Bolts in refrigerant line
- Bolt together again after removing restrictor.
13 - Condenser
14 - High pressure side connection on refrigerant circuit
- Different versions depending on vehicle.
15 - Adapter to connection for high pressure side on refrigerant circuit
- Different versions depending on vehicle.
- From VW/Audi passenger vehicle set adapter chest VAS 6338/1.
16 - Charge hose for refrigerant circuit flushing device
- From connection to high pressure side of A/C compressor on refrigerant circuit (smaller diameter) to input of Refrigerant Circuit Flushing Device VAS 6336/1 or Refrigerant Circuit Flushing Device VAS 6337/1.
17 - Flushing equipment for refrigerant circuits
- Different versions and different construction, e.g. refrigerant circuit flushing device VAS 6336/1 or refrigerant circuit flushing device VAS 6337/1.
- With filter, sight glass, safety valve, heating, refrigerant vessel 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 output of refrigerant circuit flushing device (to guarantee correct direction of refrigerant flow during flushing).
18 - Refrigerant hose of A/C service station
- From the low pressure side of the service station (mostly blue) to the output of the flushing device for refrigerant circuits.

Refrigerant Circuit with Expansion Valve, Fluid Reservoir and Second Evaporator

NOTE:
- This block diagram shows a refrigerant circuit with expansion valve, fluid reservoir and second evaporator (optional equipment on certain vehicles).
- On vehicles with expansion valve and fluid reservoir, the expansion valve is removed and replaced by an adapter. Depending on vehicle, fluid reservoir is flushed or dryer cartridge is removed. Depending on fluid reservoir version, it is to be removed and line connections to fluid reservoir are to be connected to each other with two adapters and a charging hose.
- On a vehicle with only one evaporator, the components as of position "16" are not installed or are not required.







1 - A/C service station
- With electronics and a flushing program, e.g. A/C service station with flushing device VAS 6380 or A/C service station with flushing device VAS 6337.
- If an A/C service station without program is used for flushing, the procedure should be performed manually.
- Extract the refrigerant, if necessary.
- Set up Refrigerant Circuit Flushing Device VAS 6336/1 or Refrigerant Circuit Flushing Device VAS 6337/1 between service station and refrigerant circuit return line.
- Evacuate refrigerant circuit for 20 minutes and then charge with 4 kg refrigerant R134a. Then extract again and repeat the procedure 2 more times. If the refrigerant in the sight glass(es) is not clear after the 3rd procedure, an additional procedure is necessary.
2 - Refrigerant hose of A/C service station
- From high pressure side of A/C service station (mostly colored red) to low pressure side connection of A/C compressor on refrigerant circuit (larger diameter).
3 - Adapter to connection for low pressure side on refrigerant circuit.
- Different versions depending on vehicle.
- From VW/Audi passenger vehicle set adapter chest VAS 6338/1.
4 - Low pressure side connection on refrigerant circuit.
- Different versions depending on vehicle.
5 - Adapter for the removed expansion valve.
- Different versions depending on vehicle.
- From VW/Audi passenger vehicle set adapter chest VAS 6338/1.
6 - Evaporator
7 - Connection to fluid reservoir
- Different versions depending on vehicle.
- Not present on vehicles with a dryer cartridge in fluid reservoir on condenser or a fluid reservoir installed in the condenser.
8 - Adapter for bridging the removed fluid reservoir
- Not required for all vehicles.
- Different versions depending on vehicle.
- From VW/Audi passenger vehicle set adapter chest VAS 6338/1.
9 - Refrigerant charge hose.
- Charge hose VAS 6338/31 (from VW/Audi passenger vehicle set adapter chest VAS 6338/1 ) for example.
10 - Condenser
- If a fluid reservoir with dryer cartridge is installed on the condenser, dryer cartridge must be removed (seal again the fluid reservoir on or in the condenser after removing).
- If fluid reservoir is built directly on the condenser, fluid reservoir is to be removed and replaced only after flushing.
11 - High pressure side connection on refrigerant circuit
- Different versions depending on vehicle.
12 - Adapter to connection for high pressure side on refrigerant circuit
- Different versions depending on vehicle.
- From VW/Audi passenger vehicle set adapter chest VAS 6338/1.
13 - Charge hose for refrigerant circuit flushing device
- From connection to the high pressure side of the A/C compressor on the refrigerant circuit (smaller diameter) to input of refrigerant circuit flushing device.
14 - Flushing equipment for refrigerant circuits
- Different versions and different construction, e.g. refrigerant circuit flushing device VAS 6336/1 or refrigerant circuit flushing device VAS 6337/1.
- With filter, sight glass, safety valve, heating, refrigerant vessel 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 output of refrigerant circuit flushing device (to guarantee correct direction of refrigerant flow during flushing).
15 - Refrigerant hose of A/C service station
- From the low pressure side of the service station (mostly blue) to the output of the flushing device for refrigerant circuits.
16 - Adapter to seal output to second evaporator
- Only required for certain vehicles with optional equipment "2nd evaporator".
- From commercial vehicle set adapter chest VAS 6338/50.
17 - Adapter to seal output to second evaporator
- Only required for certain vehicles with optional equipment "2nd evaporator".
- From commercial vehicle set adapter chest VAS 6338/50.
18 - Low pressure side connection on refrigerant circuit to second evaporator
- Different versions depending on vehicle.
- Only present on certain vehicles with optional equipment "2nd evaporator".
19 - High pressure side connection on refrigerant circuit to second evaporator
- Different versions depending on vehicle.
- Only present on certain vehicles with optional equipment "2nd evaporator".
20 - Adapter for the removed expansion valve on second evaporator.
- Different versions depending on vehicle.
- Only required for certain vehicles with optional equipment "2nd evaporator"
- From commercial vehicle set adapter chest VAS 6338/50.
21 - Second evaporator
- Only present on certain vehicles with optional equipment "2nd evaporator".
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