GF83.20-D-0002H Heater, Function

GF83.20-D-0002H Heater, Function

- except CODE (HH9) Regulated air conditioning (Tempmatic)

The heater enables a pleasant interior climate for the vehicle passengers in the event of different weather conditions. The heater unit is regulated by the following switches integrated in the AAC [KLA] control and operating unit (S98):
- Front temperature selection switch
- Air distribution switch
- Blower switch (S98s1)
- Air recirculation mode button (S98s6)
- Rear air conditioning button (S98s7), with code (H13) Additional heat exchanger in load compartment
- Rear temperature selection switch (S98s15), with code (H13) Additional heat exchanger in load compartment
- Rear blower switch (S98s16), with code (H13) Additional heat exchanger in load compartment

Control of the temperature and air circulation is performed manually using the blend air and lock-up flap as well as the air distribution flaps. These are mechanically adjusted via cables.
Regulation of the fresh or recirculated air is done using the fresh air and air recirculation flap. This is adjusted by the fresh air/air recirculation flap actuator motor (M16/21).
The following partial functions are summarized in the heater unit:
- Ventilation
- Heater with manual temperature control
- Heating circuit
- Actuation of rear heater, with code (H13) Additional heat exchanger in load compartment

Ventilation
Ventilation ensures air circulation in the vehicle interior. The user can select between fresh air or air recirculation mode. Selection is made using the air recirculation mode button. The blower switch and the air distribution switch are used to control the rate of circulation and the distribution of the fresh or recirculated air.
The aspirated fresh or recirculated air is distributed in the vehicle interior via the air distribution flaps and the air outlets.

Heater with manual temperature control
The front temperature selection switch is used to set the desired temperature in the vehicle interior. The position of the blend air and lock-up flap is adjusted to set the required temperature. This in turn regulates the air volume of fresh air or recirculated air which is routed over the heated front heat exchanger.

Heating circuit
The cooling water is heated in the cooling water circuit by the engine. Following this, the heated coolant is routed over the heating water feed device through the front heat exchanger, which dissipates the heat to the aspirated fresh air or recirculated air. The coolant is then returned into the cooling water circuit via the heating water return. The coolant pump serves to circulate the coolant in the cooling-water circulation. The coolant permanently flows through the front heater heat exchanger.

Actuation of the rear heater, with code (H13) Additional heat exchanger in passenger compartment
The rear heater is actuated using the rear air conditioning button integrated in the AAC [KLA] control and operating unit.
This in turn makes it possible to control the rate of air flow using the rear blower switch integrated in the AAC [KLA] control and operating unit and to regulate the temperature in the passenger compartment or load compartment using the integrated rear temperature selection switch.