Air Conditioning System

The air conditioning control system comprises relays, thermostat, pressure switches, and a control panel. Together these controls, in conjunction with the cooling fan, compressor clutch and blower, enable minimal input to maintain the required environment inside the vehicle.

Selecting air conditioning provides the added facility of cooled air available to be mixed with warm air from the heater system to give the required interior environmental conditions.

Trinary pressure switch
This switch, located in the high pressure line between the receiver drier and the expansion valve, monitors refrigerant pressure and by means of the relay controls the following system functions:
1. Refrigerant pressure drops below 2.0 bar, 29 lbf/sq.in (due to possible leakage), the compressor's electro-mechanical clutch is dis-engaged.
2. When pressure rises above 2.0 bar, 29 lbf/sq.in the compressor's clutch is re-engaged.
3. Refrigerant pressure rises above 32 bar, 455 lbf/sq.in (due to possible blockage), even with cooling fan operation, the compressor's electro-mechanical clutch is dis-engaged. When the pressure drops below 26 bar, 375 lbf/sq.in the compressor clutch is re-engaged.

Condenser cooling fan
The condenser cooling fan operates automatically whenever the air conditioning system is switched on.





1. Blower control
The blower can be operated at various speeds by turning the blower switch to the required position. When the blower is switched off, the air conditioning system will not operate.
2. Temperature control
Rotate the temperature control switch clockwise to increase the cooling effect. Use in conjuction with the blower control as required.