Tempmatic (TM), function

 On vehicles with code (HH9) Regulated air conditioning (Tempmatic), the engine residual heat utilization function can be used via the circulation pump (M13/4) up to August 31, 2008. As of September 1, 2008, this is only possible if one of the following special equipment packages is also installed:

- Code (HZ5) 10 kW auxiliary water heater with timer

- Code (HZ9) Heater booster, diesel

- Code (H12) Auxiliary heater (warm water)

- Code (H13) Additional heat exchanger in cargo area

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The Tempmatic (TM) enables a pleasant interior climate for the vehicle passengers in the event of different weather conditions.

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The TM is a semi-automatically regulated air conditioning system and is controlled and regulated by means of the following temperature sensors, buttons and switches integrated in the AAC [KLA] control and operating unit (S98):

- Interior temperature sensor (S98b1)

- Rear blower control button (+) (S98s2), with code (H13) Additional heat exchanger in cargo area, with code (HH7) Additional air conditioning in rear or with code (H08) High-performance air conditioning

- Rear blower control button (-) (S98s3), with code (H13) Additional heat exchanger in cargo area, with code (HH7) Additional air conditioning in rear or with code (H08) High-performance air conditioning

- AC OFF and residual heat system button (S98s4)

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- Reheat/defrost mode button (S98s5)

- Air recirculation mode button (S98s6)

- Rear air conditioning button (S98s7), with code (H13) Additional heat exchanger in cargo area, with code (HH7) Additional air conditioning in rear or with code (H08) High-performance air conditioning

- Air distribution switch (S98s8)

- Blower control button (+) (S98s10)

- Blower control button (-) (S98s11)

- Temperature selection switch (S98s14)

- Rear temperature selection switch (S98s15), with code (H13) Additional heat exchanger in cargo area, with code (HH7) Additional air conditioning in rear or with code (H08) High-performance air conditioning

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The air circulation for the TM is controlled electrically via the air distribution flaps. These are adjusted electrically by means of the air distribution actuator motor (M16/22). The temperature is regulated depending on the outside temperature, the temperature in the vehicle interior, and the specified temperature set. Regulation takes place by means of the blend air and shutoff flap, which is adjusted by the blend air flap actuator motor (M16/8), and by means of the refrigerant compressor (A9), which is regulated by the refrigerant compressor control valve (A9y1).

With "MAX heating" (the temperature selector switch is turned all the way to the right into the detent position) or with "MAX cooling" (the temperature selector switch is turned all the way to the left into the detent position), no more regulation takes place.

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Regulation of the fresh air or recirculated air is performed using the fresh air and air recirculation flap. This is adjusted by the fresh air/air recirculation flap actuator motor (M16/21).

The TM is divided into the following subfunctions:

 Ventilation

 Heating circuit

 Refrigerant circuit

 Temperature control

 Residual engine heat utilization system

 Actuation of rear air conditioning, with code (HH7) Additional air conditioning in rear or with code (H08) High-performance air conditioning

 Actuation of rear heater, with code (H13) Additional heat exchanger in load compartment

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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 rate of circulation and the distribution of the fresh or recirculated air are controlled using the blower control button (+), the blower control button (-) as well as the air distribution switch. The suctioned fresh or recirculated air is distributed in the vehicle interior by means of the air distribution flaps, the air ducts and the air outlet nozzles.

Heating circuit

The coolant is heated in the coolant circuit by the engine. Next, the heated coolant is routed via the heating water feed through the front heater heat exchanger, which dissipates the heat to the air in the vehicle interior. The coolant is then returned to the coolant circuit via the heating water return. The coolant pump as well as the circulation pump integrated into the heating water feed ensure circulation of the coolant in the coolant circuit.

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Coolant always flows through the front heater heat exchanger.

Refrigerant circuit

The refrigerant compressor compresses the refrigerant vapor which is heated up during the process. Next, the refrigerant vapor is forwarded to the front condenser, where it is cooled down and thus becomes liquid (condenses). After being cleaned in the front desiccant cartridge, the liquid refrigerant is routed to the front evaporator via the front expansion valve. The refrigerant evaporates and cools down the fresh or recirculated air that is flowing by. The refrigerant compressor draws in the coolant which has turned gaseous through the collection of heat.

Temperature control

The temperature selector switch is used to set the desired temperature in the vehicle interior. The position of the blend air and shutoff flap is adjusted depending on the desired temperature via the blend air flap actuator motor.

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The volume of the fresh air or recirculated air which is routed over the heated front heater heat exchanger or the front evaporator is thus controlled as a function of the outside temperature, the temperature of the vehicle interior and the set specified temperature.

Engine residual heat utilization system

The engine residual heat utilization makes it possible to heat the vehicle in the event of "circuit 15 OFF" (ignition off) for a period of 30 min. For this purpose, the residual engine heat utilization system (REST) uses the residual heat from the engine, whereby it is blown into the passenger compartment by the blower motor (M2). The circulation pump ensures circulation of the coolant in the coolant circuit.

Actuation of rear air conditioning, with code (HH7) Additional air conditioning in rear or with code (H08) High-performance air conditioning

In vehicles with code (HH7) Additional air conditioning in rear, the rear automatic air conditioning is switched on and off using the rear air conditioning button.

In vehicles with code (H08) High-performance air conditioning, a more powerful rear automatic air conditioning is also switched on and off using the rear air conditioning button.

This makes it possible to control the ventilation using the rear blower control button (+) and the rear blower control button (-) as well as to control the temperature of the passenger or load compartment using the rear temperature selection switch.

Actuation of rear heater, with code (H13) Additional heat exchanger in load compartment

Actuation of the rear heater also takes place using the rear air conditioning button.

This makes it possible to control the ventilation using the rear blower control button (+) and the rear blower control button (-) as well as to control the temperature of the passenger or load compartment using the rear temperature selection switch.