Refrigerant Circuit, Evacuating with A/C Service Station

WARNING: This page does not describe the selected car, but rather 17 other vehicles, including the 2009 Audi S4, 2009 Audi A4, 2008 Audi S4, 2008 Audi RS 4, and 2008 Audi A4. However, it is still accessible from the selected car via links, so may be relevant.

The work procedure is always to be performed as described in the operating instructions for the A/C service station.

Quantity of refrigerant oil in circuit checked and if necessary corrected → Refrigerant R134a/Refrigerant Oil Capacities and Specifications

Quantity of refrigerant in A/C service station checked

The refrigerant circuit must be evacuated before it is filled with refrigerant. Moisture is also extracted from the circuit.

Evacuation:

Switch off ignition.

Connect A/C service station to power supply.

Connect charging hoses of A/C service station to vehicle refrigerant circuit with quick-release coupling adapter (refer to vehicle-specific refrigerant circuit) → 87 - Air conditioning .

Screw in handwheel of quick-release coupling adapters until valves of service connections are definitely open (take care not to strain valve).

NOTE:

If pressure is to be measured after charging system on vehicles with a service connection on one side of the refrigerant circuit only, use valve adapter and charging hose with valve opener → A/C Service Station, Connecting .
Switch on A/C service station and evacuate refrigerant circuit for at least 30 minutes. The pressure reading must indicate an absolute pressure of less than 10 mbar (corresponding to 990 mbar vacuum).

NOTE:

At this pressure, both green LEDs light for example on A/C service station V.A.G 1885 (currently available A/C service stations → Catalog V.A.G tools ).
Switch off A/C service station and allow to stand for at least 1 hour.
If the vacuum display (LED chain) does not change, the system is free of leaks and can be charged.

NOTE:

A current vacuum reading (LED) is only obtained using A/C service station V.A.G 1885 , for example (currently available A/C service stations → Catalog V.A.G tools ) after pressing the "Evacuate" button again.

Fig 1: A/C Service Station

Courtesy of VOLKSWAGEN UNITED STATES, INC.

If with this A/C service station the upper (green) LEDs do not light immediately after switching on, either the refrigerant circuit is leaking or there is still residual moisture/refrigerant in the circuit.

Proceed as follows if the vacuum is not maintained:

Fill the circuit with 100 g of refrigerant, localize any leaks using leak detector and eliminate accordingly.

Evacuate and again observe the vacuum display over a period of hours. Charging may only be performed if vacuum is maintained.