GF83.50-D-0001H Rear Air Conditioning, Function

GF83.50-D-0001H Rear Air Conditioning, Function

- with CODE (HH7) Additional air conditioning in rear

The rear automatic air conditioning can only be actuated or regulated using the rear blower control button (+) (S98s2) and the rear blower control button (-) (S98s3), which are integrated into the KLA control and operating unit (S98), and using the rear temperature selection switch (S98s15) integrated into the KLA control and operating unit, if it is switched on using the rear air conditioning button (S98s7) integrated into the KLA control and operating unit. Activation of the rear automatic air conditioning is indicated by illumination of the red light emitting diode (LED) in the rear air conditioning button.
The rear automatic air conditioning enables a pleasant interior climate to be set in the passenger or load compartment of the vehicle during different weather conditions.
Actuation and subsequent regulation of the air is performed electrically via the blower regulator (A32/2a1) which regulates the blower motor (A32/2m1).
Depending on the interior temperature in the passenger or load compartment of the vehicle and on the set specified temperature value, temperature regulation is performed electrically via the blend air flap actuator motor (A32/2m2), the refrigerant compressor control valve (A9y1) and over the refrigerant shutoff valve (A32/2y1) with the integrated rear expansion valve.
The rear automatic air conditioning can be summarized by the following subfunctions:
- Rear air conditioning system ventilation
- Rear air conditioning system refrigeration circuit
- Rear air conditioning temperature control

Rear air conditioning system ventilation system
The ventilation system ensures circulation of the recirculated air in the passenger or load compartment of the vehicle.

Ventilation is only provided in air recirculation mode, no fresh air is drawn in.

The rear blower control button (+) and the rear blower control button (-) are used to regulate the rate of circulation of recirculated air.The recirculated air is distributed over the roof air duct and the air outlets which can be swiveled and closed.

Rear air conditioning refrigeration circuit
The refrigerant compressor (A9) compresses the gaseous refrigerant, which causes it to heat up. Next, the refrigerant vapor is forwarded to the front condenser, where it is cooled down and thus liquifies (condenses). After cleaning in the front desiccant cartridge the liquid refrigerant is routed over the front expansion valve into the front evaporator and simultaneously over the refrigerant shutoff valve using the integrated rear expansion valve into the rear evaporator.
The refrigerant evaporates and cools down the recirculated air that is flowing past. The refrigerant compressor draws in the coolant which has turned gaseous through the collection of heat.

Rear air conditioning temperature control
The rear temperature selection switch is used to set the temperature required in the passenger or load compartment of the vehicle.
Depending on the temperature required, the position of the blend air and shutoff flap is adjusted over the blend air flap actuator motor, the refrigerant compressor regulated over the refrigerant compressor control valve and the refrigerant supply to the front evaporator closed or opened and regulated by way of the refrigerant shutoff valve using the integrated rear expansion valve. This enables the recirculated air flow, which is routed over the rear evaporator, and the refrigerant, which is routed over the rear evaporator, to be regulated to match the interior temperature in the passenger or load compartment of the vehicle.