2. Start the engine and set the operating mode to 2000 rpm. Turn on the air conditioner, set the temperature control switch to the maximum cooling position and the heater electric fan switch to the high speed position.
3. Leave all windows and doors of the car open.
4. Place "dry" thermometer (dry bulb thermometer) in the deflector supplying cold air.
5. Place the psychrometer as close as possible to the air intake in the cabin (the place of air intake from the cabin to the evaporator).
6. Verify that the pressure in the high pressure line of the system is 1373-1575 kPa. If the pressure is higher than the specified value, then cool the condenser by pouring water on it. If the pressure is below the specified value, then close the front of the condenser.
7. Check that the air temperature value measured "dry" thermometer near the air intake in the cabin is between 25 and 35°C.
8. Determine the relative humidity of the air (V %) according to the schedule below. Determination of relative humidity is carried out according to indications "dry" And "wet" psychrometer thermometers near the air intake in the cabin.
Note: an example of determining the relative humidity of the air according to the graph: if the readings "dry" thermometer - 25°С, readings "wet" thermometer - 19.5°C, then the point of intersection of the dotted lines corresponding to the temperature values gives a relative humidity value of 60%.
9. Measure the temperature of the chilled air at the outlet of the deflector and calculate the temperature difference between the inlet and outlet of the evaporator from the readings "dry" thermometers (at the air intake in the cabin and at the deflector).
10. Check that the relative humidity and temperature differences are within the nominal value range (those. the intersection of the lines corresponding to relative humidity and temperature difference are between the two shaded lines). In this case, the efficiency of the air conditioner is normal.