Procedure
1. Install the pressure gauge on the line.
2. Start the engine, let it run at 2000 rpm⁻¹ and set the maximum cooling mode with high fan speed.
3. Open all windows or doors.
4. Install the thermometer in the air supply grille of the vehicle interior.
5. Install wet and dry bulb thermometers as close to the cooling unit inlet as possible.
6. Check that the pressure shown by the pressure gauge is between 1.373 and 1.575 kPa. If the pressure is too high, pour water onto the condenser. If the pressure is too low, close the front side of the condenser.
7. Check that the air temperature in the air supply grille into the vehicle interior is between 25–35°C.
8. Use the graph to calculate the relative humidity by comparing the temperature of the wet and dry thermometers.
9. Measure the temperature in the air supply grille of the car interior and calculate the difference using a dry thermometer and a thermometer in the air supply grille.
(The original text is published on the website: hyundaibook)
10. Check that if the intersection of relative humidity and temperature difference are within the tolerance range, then the air conditioning system is working normally.