Heating & ventilation (Operation): Description and operation

Operation

Air, drawn through the intake below the windscreen, passes through the blower unit, heater duct and heater unit to enter the interior of the car.

When the temperature control is rotated towards the heated air position it opens a water valve in the engine cooling system allowing hot water from the engine to circulate through the heater matrix. Rotation of the temperature control also adjusts the position of the blend flap in the heater unit to direct all, or a proportion of, the intake air through the heater matrix to be heated before entering the car interior.

The distribution of air entering the car through the heater is dependent on the positions of distribution flaps inside the heater unit. The distribution flaps are adjusted by rotation of the distribution control to direct the air in various proportions to the vents at face level, foot level and windscreen.

When the blower switch is switched off, the volume of air entering the blower unit depends on the ram effect of the car’s forward motion. Four fan speeds are also available on the switch to supplement the ram effect.

The air supply control provides the facility to recirculate air inside the car in conditions when it is desirable not to draw in outside air. The control operates a recirculation motor in the blower unit.

Operation of the face level air flow control will provide unheated blown air at the centre face level vents, provided the distribution control is set not to supply air at face level.

When the distribution control is set to supply air at face level, the unheated air supplied by the face level air flow control will blend with the air supplied by the air distribution control.