Refrigerant Circuit, Charging
The entire refrigerant capacity can be filled either in the high or low pressure side, the following describes the charging the refrigerant circuit on the high pressure side.
Refrigerant and refrigerant oil capacities. Refer to Technical Data (vehicle-specific service information).
- Perform the procedure as described in the A/C Service Station Owner's Manual. Refer to A/C Service Station Owner's Manual.
- Before adding the refrigerant, correct the quantity of refrigerant oil. Refer to Technical Data (vehicle-specific service information).
- Make sure the A/C Service Station is on the same level as the vehicle whose refrigerant circuit is to be charged (maximum difference 50 cm) when charging the refrigerant circuit. If a difference in height is too large, a difference between the amount of refrigerant displayed on the service station and the actual amount filled in the circuit may result (depending on the version of the A/C Service Station). The filling precision of the A/C Service Station may change.
- Completely reassemble the refrigerant circuit. Refer to Refrigerant Circuit (vehicle-specific service information).
-- On vehicles with a high-voltage system, switch off (deactivate) the "auxiliary climate control" function. Refer to the Owner's Manual and Infotainment/MMI Operating Manual.
-- Switch off the ignition.
-- Connect the A/C Service Station to the power supply.
-- Check and if necessary correct the refrigerant quantity, the quantity of refrigerant oil and the quantity for the UV additive for leak detection in the A/C Service Station. Refer to A/C Service Station Owner's Manual.
Additionally on vehicles with electric operated valves in the refrigerant circuit, which cannot be opened without power:
For vehicles with a high-voltage system and additional A/C system functions ("heat pump operation" or "cooling the high-voltage battery"), valves may be installed in the refrigerant circuit that cannot be opened without current. These valves are opened and closed for example via a step motor and after switching off the ignition are no longer activated. To completely discharge, correctly evacuate and charge the refrigerant circuit, no sections may be closed. Therefore these valves must be opened before performing this work. Refer to Refrigerant Circuit (vehicle-specific service information) and use the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
-- Open the electrically activated valves (not open without current) using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
All Vehicles
-- Start the A/C Service Station according to its operating instructions. Refer to the A/C Service Station Operating Instructions.
-- Remove the closure caps from the refrigerant circuit service connections (refer to the vehicle-specific refrigerant circuit. Refer to Refrigerant Circuit (vehicle-specific service information).
-- Connect the quick-release couplings to the refrigerant circuit service connections. Refer to A/C SERVICE STATION ON REFRIGERANT CIRCUIT, CONNECTING .
-- Evacuate the refrigerant circuit using the A/C Service Station. Refer to REFRIGERANT CIRCUIT, EVACUATING .
-- Adjust the specified refrigerant oil quantity and if necessary the specified quantity of refrigerant oil and the quantity of the UV additive for leak detection on the A/C Service Station. Refer to A/C Service Station Owner's Manual and Technical Data (vehicle-specific service information).
-- Adjust on the A/C Service Station that the refrigerant will be filled on the high pressure side. Refer to the A/C Service Station Owner's Manual.
When charging the refrigerant circuit via the low pressure side, liquid refrigerant can get into the compression chamber of the A/C compressor.
-- If it is necessary to fill the refrigerant circuit via the low pressure side, turn the A/C compressor after filling before the first activation 10 turns by hand (if necessary for example remove the input shaft to do so).
The refrigerant and the refrigerant oil are filled via the high pressure side in the refrigerant circuit.
If on a vehicle no service connection is present on the high pressure side of the refrigerant circuit, the refrigerant may be filled via a service connection on the low pressure side. To do this pay attention to the adjustment and the A/C Service Station Owner's Manual.
If on the A/C Service Station the filling direction cannot be set if necessary remove (close) the hand wheel on the quick-release coupling adapter on the low pressure side.
-- Fill the refrigerant circuit with the specified refrigerant quantity if necessary fill the specified quantity refrigerant oil and the quantity of the UV additive.
-- Switch on the A/C system after filling. Refer to A/C SYSTEM, STARTING AFTER CHARGING REFRIGERANT CIRCUIT (vehicle-specific service information) and Refer to A/C SYSTEM, OPERATING AFTER CHARGING .
A/C System, Operating with Electrically Driven A/C Compressor
-- Activate the A/C compressor via the "Basic Setting, Compressor Cut-In" function from Guided Fault Finding using the Vehicle Diagnostic Tester .
Additionally on vehicles with electric operated valves in the refrigerant circuit, which cannot be opened without power:
-- The Vehicle Diagnostic Tester enables the activation of the electrically activated valves (not open without current) for A/C system operation via the respective control module (to open or close). Use the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
For vehicles with a high-voltage system and additional A/C system functions ("heat pump operation" or "cooling the high-voltage battery"), valves may be installed in the refrigerant circuit that cannot be opened without current. These valves are opened and closed for example via a step motor and after switching off the ignition are no longer activated. To completely discharge, correctly evacuate and charge the refrigerant circuit, no areas may be closed. Therefore these valves must be opened before these procedures. After finishing work on the activation of these valves are enabled via the respective control module. Refer to Refrigerant Circuit (vehicle-specific service information) and the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
All Vehicles
Should a function test be performed after charging the refrigerant circuit?
-- Check the pressures in refrigerant circuit. Refer to PRESSURES, CHECKING .
Should a function test not be performed after charging the refrigerant circuit?
-- Disconnect the A/C Service Station from the refrigerant circuit and turn it off. Refer to A/C SERVICE STATION, SWITCHING OFF AND DISCONNECTING FROM REFRIGERANT CIRCUIT .