Quick check of the air conditioning system operation (using the 901 series minibus as an example, - for M-class models the check is carried out in a similar manner)
1 - Temperature meter; 2 - Receiver-dryer viewing window; 3 - Refrigerant leak detector
1. Illustrative material for a quick check of the air conditioning system is presented in the illustration, to which all references in the text refer.
2. Drive the car into the shade, open all the windows.
3. Move the temperature mode selector knob to the COLD position.
4. Turn on the fresh air supply mode.
5. Fully open the flow sections of the nozzles of all air ducts.
6. Start the engine at idle speed.
7. Turn on the K/V - the engine speed should increase.
8. Turn on the maximum speed mode of the fan.
9. Through the viewing window of the receiver-dryer (2), make sure that there are no signs of refrigerant bubbling.
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Note: When starting a freshly charged system for the first time, the formation of air bubbles should not be a concern - wait about 10 minutes - the bubbles should disappear.
10. Carefully examine the external condition of all components of the refrigeration system, using a special detector, check them for signs of developing leaks.
11. Set the fan to speed mode "1" and measure the temperature of the air coming out through the central deflectors of the instrument panel using a special meter (1). After 5 minutes of system operation, the temperature of the air supplied to the passenger compartment should be within the range of +2°C÷+12°C, and the A/C compressor should switch to cyclic mode (on-off), otherwise, check the condition of the evaporator temperature switch sensor.
12. Turn off the air conditioner and stop the engine - more detailed checks of the air conditioning system should be performed in a car service workshop.