Climate Control

Operation
The A/C compressor, the evaporator control and the [1][2]auxiliary fan stage 1 are switched on when the A/C or recirculated air button is pressed.

Evaporator sensor
The magnetic clutch of the A/C compressor is switched off by the A/C relay and the [1][2]auxiliary fan stage 1 is also switched off when the evaporator sensor reaches a temperature of < 2°C (36°F). This feature prevents the evaporator from icing up. At an evaporator sensor temperature of > 3°C (38°F), the control unit once again switches on the A/C relay and the auxiliary fan stage 1 and the magnetic clutch energizes.

Pressure switch
In order to improve the cooling capacity, the [1][2]auxiliary fan stage 2 is switched on by a medium pressure switch when the refrigerant pressure increases to above 18 bar. The auxiliary fan stage 2 is switched off once again when the pressure drops below 15 bar. The activation circuit for the A/C compressor clutch leads from the output of the A/C relay (working circuit) to the refrigerant high pressure switch and via the low pressure switch to the A/C compressor clutch. If one of the pressure switches has cut out due to too little or too much pressure in the refrigerant circuit (no or too little refrigerant or too much refrigerant) the A/C compressor clutch disengages in order to protect the A/C compressor from being damaged.