A/C System, Operating After Charging
If the mechanically driven Air Conditioning (A/C) compressor was removed, rotate it approximately 10 times by hand before using it for the first time (during or after installing, for example before installing the belt) to prevent damage caused by liquid impact when first switched on (any oil in compressor cylinder is forced out on rotation).
If the electronically driven A/C compressor was removed, activate it after filling the A/C compressor before the A/C system on via the "basic setting, compressor cut-in" function for the Guided Fault Finding. Use the Vehicle Diagnostic Tester in the"Guided Fault Finding" Function for A/C System and Battery Regulation. This prevents the A/C compressor from being damaged, for example, by liquid impact when it is first switched on (any oil in the A/C compression chamber is forced out).
The vehicle engine drives the mechanically driven A/C compressor via a belt or shaft. The electronically driven A/C compressor is driven via an electric motor attached directly to the A/C compressor (for example on hybrid vehicles).
Operating an A/C System with a Mechanically Driven A/C Compressor
-- Start engine with compressor switched off (version with A/C clutch).
-- Set compressor to minimum output, for example, "Econ" or A/C off mode (version with no A/C clutch with regulating valve).
-- Wait until idle speed has stabilized.
-- Switch on the compressor and operate the system for at least two minutes at idling speed.
-- If necessary, check pressures in the refrigerant circuit using the A/C service station.
-- Turn the engine off.
-- Screw out the hand wheel on the quick-release coupling adapter.
-- Disconnect the charging hoses from the refrigerant circuit.
-- Install the caps.
Operating an A/C System with an Electrically Driven A/C Compressor
-- Operate the A/C compressor using "basic setting, compressor cut-in" in Guide Fault Finding. Use the Vehicle Diagnostic Tester"Guided Fault Finding" A/C System and Battery Regulation.
Additionally on vehicles with an electric operated valves in the refrigerant circuit, which cannot be opened without power (for example the Audi Q7 e-tron):
-- Via the Vehicle Diagnostic Tester the electrically activated valves which do not open without power for the operation of the A/C system enable the activation of these valves via the respective control module (to open or close) using the Vehicle Diagnostic Tester in the"Guided Fault Finding" function.
On vehicles with high-voltage system and additional functions of the A/C system ("heat pump operation" or "cooling the high-voltage battery") valves may be installed in the refrigerant circuit which cannot be opened without power. These valves are opened and closed for example via a step motor and after switching off the ignition are no longer activated. To completely drain, correctly discharge and charge the refrigerant circuit no areas may be closed, for this reason the valves must be opened before these procedures. After completing the work on the refrigerant circuit, use the respective control module to re-activate the triggering of the valves, which are controlled by stepper motors, for example. Refer to Refrigerant Circuit and use the Vehicle Diagnostic Tester in the"Guided Fault Finding" function.
All
-- After the basic setting and If necessary, check pressures in refrigerant circuit using A/C service station. Refer to A/C SERVICE STATION, CONNECTING FOR MEASURING AND TESTING .
-- Screw out the hand wheel on the quick-release coupling adapter.
-- Disconnect the charging hoses from the refrigerant circuit.
-- Install the caps.