General Information

WARNING: This page is about a different car, the 2022 Audi S3, 2022 Audi RS 3, 2022 Audi A3 Quattro, and 2022 Audi A3. However, it is still accessible from the selected car via links, so may be relevant.

Compressed air and nitrogen are to be used in order to force out moisture and other contaminants as well as old refrigerant oil as efficiently as possible, without wasting refrigerant. In the refrigerant circuit is to be cleaned (flush with refrigerant R134a or blow through with compressed air and nitrogen)

NOTE:

For the most part, blowing through the refrigerant circuit with compressed air and nitrogen requires significantly more work than cleaning (flushing) with refrigerant R134a. As cleaning (flushing) with refrigerant R134a cleans the components more efficiently, always flush in case of a complaint (blowing through should only be used for certain complaints and individual components).

Under certain conditions it may be sufficient to blow through certain components (for example individual refrigerant lines or refrigerant hoses) with compressed air and nitrogen (for example for purposes of forcing out old refrigerant oil from individual components that were removed).

Certain contaminants cannot or can only be insufficiently removed from the refrigerant circuit with compressed air, these contaminants can be removed, for example by cleaning (flushing) with refrigerant R134a. Refer to REFRIGERANT CIRCUIT, CLEANING (FLUSHING) WITH REFRIGERANT R134A .

When blowing through, the maximum work pressure of 15 bar (217 psi) must not be exceeded (corresponding to pressure that is reached in a filled refrigerant circuit with an ambient temperature of approximately 60 °C (140 °F), if necessary use pressure reducer also for compressed air)

WARNING:

Nitrogen can leak uncontrolled from the cylinder.
Make exclusive use of pressure reducers for nitrogen cylinders (maximum work pressure 15 bar (217 psi)).
Use appropriate extraction units to draw off gas mixture escaping from components.

-- Always flush components in direction opposite to refrigerant flow.

NOTE:

Restrictor, expansion valve, compressor, receiver and reservoir cannot be flushed with compressed air and nitrogen.

-- Remove this dryer cartridge on condensers that have one installed in the integrated receiver/dryer.

NOTE:

If the receiver/dryer or dryer cartridge is integrated in the condenser, then they cannot be replaced separately and the condenser must be replaced after cleaning (flushing).

Receivers/dryers where it is possible to replace the dryer cartridge have an additional filter, which must also be replaced with the dryer cartridge.

-- First flush out old refrigerant oil and dirt using compressed air and then use nitrogen to remove component moisture.

-- Adapter for sealing off the pressure hose to the refrigerant circuit. Refer to A/C SERVICE STATION, CONNECTING .

Note the following points to prevent oil and moisture from entering the refrigerant circuit from the compressed air system.

-- The compressed air must be routed through a compressed air purifier for cleaning and drying. For this reason use the filter and dryer for the compressed air (included in scope of delivery as tool for painting work).

-- On refrigerant lines with thread or union nut on the connection, use the adapter from the A/C Adapter Set :VAG1785 (A/C Adapter Set - Adapter 1 :VAG1785/1 through A/C Adapter Set - Adapter 8 :VAG1785/8 ) to connect charge hoses 5/8" -18 UNF (a section of this adapter is also contained in the Refrigerant Circuits Adapter Set 1 :VAS6338/1 .

-- On refrigerant lines without thread or union nut on the connection (for connecting adapters), use adapter from Refrigerant Circuits Adapter Set 1 :VAS6338/1 or a standard blower pistol with rubber mouthpiece.

NOTE:

Only blow through refrigerant circuit with compressed air and then with nitrogen if there is no possibility of cleaning (flushing) the refrigerant circuit with refrigerant R134a or the amount of work to flush individual components becomes excessive (for example minor contaminants and moisture can also be blown out of the refrigerant lines in a short period of time).

Compressed air/nitrogen emerging from components is to be drawn off by way of an appropriate system (for example, a workshop extraction system).

The circuit (or individual components) must be blown through (if there is no possibility for cleaning or flushing with refrigerant R134a is not recommended):

-- In the event dirt or other contaminants are located in individual components of the circuit.

-- If vacuum reading is not maintained on evacuating a leak-free refrigerant circuit (pressure build-up due to moisture in refrigerant circuit).

-- The refrigerant circuit has been left open for longer than normal (for example, following an accident).

-- Pressure and temperature measurements in the refrigerant circuit indicate the likelihood of moisture.

-- In the event of doubt about the amount of refrigerant oil in the circuit.

-- The A/C compressor had to be replaced on account of internal damage (for example, noise or no output).

NOTE:

Pay attentions when replacing the Electrical A/C Compressor -V470- on vehicles with electrically driven A/C compressor (if the electronic on the A/C compressor is damaged the refrigerant circuit must not always be cleaned. Refer to COMPRESSOR, REPLACING WITHOUT THE NEED FOR FLUSHING REFRIGERANT CIRCUIT .

-- If it is stipulated by the vehicle-specific Service Information following the replacement of certain components.

NOTE:

Certain contaminants and old refrigerant oil cannot or can only be insufficiently removed from the refrigerant circuit with compressed air, these contaminants can be removed, for example, by cleaning (flushing) with refrigerant R134a. Refer to REFRIGERANT CIRCUIT, CLEANING (FLUSHING) WITH REFRIGERANT R134A .