Leak Detection/Preparations For Draining

WARNING: Mixtures of R134a and compressed air must not be used for troubleshooting due to the risk of explosion at high pressures and temperatures.


NOTE: Since the A/C compressor is not equipped with high and low-pressure connections, only the operation of the low-pressure gauge (pressostat) can be checked. In this case, connection is made as usual to the drainage/filler valve.





Connect blue hose (10) to service valve. Close MAIN SWITCH (1).
Set selector switch (2) to TEST.
Start engine and switch on A/C system in car.
Low-pressure pressostat will now operate as indicated by low-pressure gauge (14).

Preparations for drainage
Before commencing work, read and observe Safety Precautions when working on A/C systems. Service Precautions Also read General Information on repair and replacement of A/C system components. General Information On Repair


WARNING: Always wear protective goggles and gloves when working with refrigerant Contact with eyes and skin may cause frostbite.


The A/C system in the car must be at least at room temperature (approx. 20 °C/68 °F) to achieve fast drainage. In winter, therefore, the car should be housed overnight in the workshop before commencing work.

The drainage time will be reduced if the A/C system has recently been in service and the engine is hot (radiation heat). If possible, run the system for about 5 minutes before draining to shorten the time.


WARNING: Mixtures of R134a and compressed air must not be used for troubleshooting due to the risk of explosion at high pressures and temperatures.