Function Test

NOTE: Observe safety rules when working on A/C systems. Test
methods for room temperatures from +20° to +40°C.

1. Vehicle should not be exposed to sunshine before or during test.
2. Check tension of V-belt for copressor drive.
3. Switch ON A/C and watch sight glass in receiver drier for flow free of bubbles soon after compressor clutch switches on. Add refrigerant if required. If the refrigerant loss amounts to more than 200g, check system for leaks.
4. Set temperature dial to "MAX".
5. Set defroster and floor levers to inside stop.
6. Open air nozzles.
7. Insert one thermometer into center nozzle and each side nozzles.
8. Remove closing caps on compressor service valves. Connect suction (blue) and high pressure (red) gauge hoses to compressor making sure pressure pins in connection nipples are at compressor.
9. Open windows and close vehicle doors. Run engine at 2000 rpm.

Pressure Chart:

LEGEND
1) = Relative Humidity of the Air
Ta = Outside Temperature (°C)
A = Air Outlet Temperature (°C)
B = Pressure in front of Compressor (bar)
C = Pressure following Compressor (bar)
D = Coolant Temperature (°C)

10. After approximately 10 minutes read values on thermometers and gauges should be no higher than specified values on tables.
11. Check cutout temperature of temperature regulator by setting blower switch to stage 1 and temperature dial to "MAX". Insert a thermometer into center nozzle. Run engine at approx. 2000rpm.
12. After third cutout of copressor clutch the air outlet temperature should be approx. +3°C, but not less than +1°C.
13. The auxiliary fan in front of condenser is switched on at coolant temperature of 100°C and refrigerant temperature of 52°C.
14. When refrigerant loss is high or or pressure in receiver drier drops below 2 ± 0.2 bar, the voltage supply to compressor is interrupted by pressure switch. When the pressure increases to 0.6 bar above cutout pressure, the circuit is closed again.
15. Remove hose lines from service valves and install closing caps.