Refrigerant Circuit, Cleaning

Special tools and workshop equipment required 

• Refrigerant Circuits Adapter Set 1 - Adapter 12:VAS 6338/12 
• Refrigerant Circuits Adapter Set 1 - Adapter 3:VAS 6338/3 
• Rinsing Adapter:VAS 6338/38A 
• A/C Service Station
• Flushing Adapter:VAS 6338/80 
• Engine Bung Set:VAS 6122 

• The following describes the procedure using an A/C service station with an integrated flushing device for R1234yf as an example.
• Flushing a contaminated refrigerant circuit is done in the opposite direction of the standard flow.
• There must be at least 6 kg (13.23 lbs) of refrigerant in the A/C service station.
• Pay attention to the A/C service station operating instructions. Refer to the Operating Instructions.

Procedure 

Immediately seal off any open lines and connections with clean plugs from the Engine Bung Set:VAS 6122  .

-- Remove the expansion valve and replace by Rinsing Adapter:VAS 6338/38A  . Refer to Expansion Valve, Removing and Installing  .

-- Remove the Refrigerant Expansion Valve 1 -N636- and install the Flushing Adapter:VAS 6338/80  in its place. Refer to Refrigerant Expansion Valve 1 -N636-, Removing and Installing  .

-- Remove the refrigerant pipes from the A/C compressor. Refer to REFRIGERANT LINES, REMOVING AND INSTALLING TO A/C COMPRESSOR, R1234YF  or REFRIGERANT LINES, REMOVING AND INSTALLING TO A/C COMPRESSOR, R744  .

-- Install the Refrigerant Circuits Adapter Set 1 - Adapter 12:VAS 6338/12  and Refrigerant Circuits Adapter Set 1 - Adapter 3:VAS 6338/3  to the refrigerant lines.

-- Remove the desiccant bag and close the receiver/dryer again. Refer to DESICCANT BAG/DRYER, REMOVING AND INSTALLING, R1234YF  or DESICCANT BAG/DRYER, REMOVING AND INSTALLING, R744  .

-- Screw on the closure caps with seals on both refrigerant circuit service connections.

Tip

The refrigerant circuit cannot be evacuated correctly without closure caps (the valves in the service connections will open from the vacuum in the refrigerant circuit and air will enter).

-- Connect the A/C Service Station -1- to the refrigerant circuit for flushing.

Courtesy of VOLKSWAGEN GROUP OF AMERICA, INC.

1. A/C Service Station
2. Refrigerant Hose for A/C Service Station, Low-Pressure Side
3. Flushing Device
4. Refrigerant Hose
5. Refrigerant Circuits Adapter Set 1 - Adapter 3:VAS 6338/3 
6. Vehicle Refrigerant Line with Connection to the A/C Compressor High Pressure Side
7. Vehicle Refrigerant Line with Connection to the A/C Compressor Low Pressure Side
8. Refrigerant Circuits Adapter Set 1 - Adapter 12:VAS 6338/12 
9. Refrigerant Hose for A/C Service Station, High-Pressure Side

-- Perform the "open the electric activated valves for the refrigerant circuit for extracting, evacuating, filling and flushing" with the Vehicle Diagnostic Tester . Refer to Diagnostic Entries .

-- Start the flushing procedure via the menu of the A/C Service Station. Refer to Owner's Manual.

Tip

The A/C Service Station will display the end of the flushing process.

-- Check the pressure in the flushing circuit. Only if it is the same or below the ambient pressure, remove the refrigerant hoses and the adapters.

-- Replace the desiccant bag. Refer to Desiccant Bag, Removing and Installing  .

-- Remove the circuit adapters and assemble the refrigerant circuit.

-- After charging the refrigerant circuit and re-energizing the high-voltage system, perform the "A/C compressor, first break-in" function using the Vehicle Diagnostic Tester . Refer to Diagnostic Entries .

Tightening Specifications

• Refer to Overview - Refrigerant Lines, R744  or Overview - Refrigerant Lines, R1234YF  .
• Refer to Overview - Evaporator Housing, R744  or Overview - Evaporator Housing, R1234YF  .