| General Procedures Service unit Refrigerant identifier | | -
CAUTION:The refrigerant identification equipment must be used before the system is emptied, otherwise the service unit may become contaminated. Contaminated refrigerant must be disposed of as hazardous waste. Always follow the manufacturer's instructions when using the service units. Remove the A/C charging connection protective caps. - Low-pressure charging connection
- High-pressure charging connection
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Pull back the catch of the quick-fit union on the line of the service unit. | | | -
NOTE:Larger inside diameter for high-pressure side. Smaller inside diameter for low-pressure side. Connect the service unit line to the A/C charging connection. | | | -
WARNING:Avoid releasing the refrigerant into the atmosphere at all costs. NOTE:When removing components of the air conditioning system, calculate the residual quantity of refrigerant oil. For additional information, refer to Refilling refrigerant oil in this section. Drain the air conditioning system via the low-pressure port in accordance with the service unit manufacturer instructions. | | | -
CAUTION:The air conditioning system must be evacuated for about 30 minutes before recharging it, to ensure that it operates correctly. CAUTION:If moisture has entered the open system over an extended period of time (several hours), renew the accumulator/dryer and extend the evacuation time to 2-3 hours. Evacuate the air conditioning system in accordance with the service unit manufacturer instructions. | | | -
NOTE:If an air conditioning system is evacuated before the refrigerant has been drained, some of the refrigerant will remain in the compressor refrigerant oil. This remaining refrigerant may evaporate, causing a slight pressure increase during the leak test. The air conditioning system is not leaking if the pressure increases by not more than 20 mbar (2 kPa, 0.29 psi). Carry out the leak test. - For the leak test, close the hand valves on the gauge set, switch off the service unit vacuum pump and observe the low pressure gauge.
- Locate any leaks in the A/C refrigerant circuit using a leak tester.
For additional information, refer to Leak location using an electronic leak tester /
Leak location using fluorescent contrast material in this section.
| CAUTION:The air conditioning system must always be evacuated before filling. | | -
NOTE:Depending on the service unit and equipment (with or without heatable filler cylinder), the air conditioning system can be filled in liquid form through the high-pressure port or in gaseous form through the low-pressure port. NOTE:Fill quantity indicated on sticker in engine compartment. Filling the air conditioning system through the high-pressure port (liquid fill). - Open the shut-off valve on the high-pressure side.
- Switch the service unit to "Fill" mode and fill the system with the prescribed quantity of liquid refrigerant (R134a).
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CAUTION:Filling the air conditioning system through the low-pressure port (gas fill only). Filling the air conditioning system through the low-pressure port. - Open the shut-off valve on the low-pressure side.
- Switch the service unit to "Fill" mode and fill the system with the prescribed quantity of gaseous refrigerant.
- Top up with the remaining refrigerant whilst the air conditioning is switched on. Let the engine run at about 1200-1500 rpm for this purpose. Switch the air conditioning to maximum cooling power and fresh air mode. Set the blower to maximum power. Allow the remainder of the prescribed amount to be drawn in.
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WARNING:Do not detach the high-pressure hose whilst the air conditioning is switched on. Disconnect the service unit. - Close the shut-off valves.
- Switch off the service unit.
- Disconnect the service unit line from the A/C charging connection.
- Screw the protective caps onto the filler valves.
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