Order of execution
1. Install a pressure gauge on the line.
2. Start the engine, let it run at 2000 rpm and set it to maximum cooling at high fan speed.
3. Open all windows or doors.
4. Install the thermometer in the air supply grille to the car interior.
5. Install wet and dry bulbs as close as possible to the inlet of the cooling unit.
6. Check that the pressure shown on the pressure gauge is between 1.373-1.575 kPa. If the pressure is too high, pour water over the condenser. If the pressure is too low, close the front side of the condenser.
7. Check that the temperature of the air in the car air supply grille is between 25-35°C.
8. From the graph, calculate the relative humidity of the air by comparing the temperature of the wet and dry bulbs.
9. Measure the temperature in the car air intake grille and calculate the difference between the dry bulb bulb and the air intake grille thermometer.
10. Check that if the intersection of relative humidity and temperature difference is within tolerance, then the air conditioning system is working properly.