Checking Function of Air Conditioner

Checking Function Of Air Conditioner

Checking operation of air conditioner

General information

NOTE: The air outlet temperatures at the centre nozzle of the dashboard and the high pressure in the air conditioner must not exceed the specified tolerance ranges after an operating time of seven minutes.

Procedure and general test prerequisites

NOTE: The safety regulations must be observed during all work on the refrigerant system. =>", =>",

1. Connect the air conditioning service unit. =>"
2. Measure outside temperature with a thermometer.
3. Open all air exhaust nozzles on the dashboard (if necessary direct the blower near the test person).
4. Insert sensor of the temperature measuring device approx. 4 cm centrally into the left-hand centre nozzle.
5. Check stopwatch and visual contact with the relevant temperature and pressure on the air conditioning service unit.
6. Switch on ignition.
7. Open driver's and passenger's side windows and close sunroof.
8. Set the temperature for both sides to maximum cooling (LO appears in the display).

NOTE: With a 4-zone-air conditioner, the rear air conditioner must also be set to maximum cooling for both sides (LO) (if necessary, use the MONO function) and the rear air exhaust nozzles left open. To activate the MONO function, the .AUTO" -adjusting lever of the front air conditioning control must be pressed longer than two seconds (MONO appears in the display).

9. Set maximum blower speed.
10. Start engine and allow to run at idle speed (do not rev engine during or after starting.)
11. Operate air conditioner for five minutes at idle speed.
12. Bring engine speed up to 2000 rpm and maintain it there. Start the time measurement immediately.
13. Note centre nozzle temperature and pressure values after two minutes.
14. Compare values (centre nozzle temperature and pressure readings) with the specified tolerances.

NOTE: If the specified nominal values are not reached, the air conditioner must be checked for leaks and repaired.

Technical values

Centre nozzle temperature as a function of outside temperature: 2-zone air conditioning







High pressure in refrigerant circuit as a function of outside temperature: 2-zone air conditioning







Centre nozzle temperature as a function of outside temperature: 4-zone air conditioning







High pressure in refrigerant circuit as a function of outside temperature: 4-zone air conditioning







Tools and materials