Heat Exchanger Sensor

Temperature Control: FB

Nominal temperature value setting
The temperature is selected separately for the driver's and passenger's side by the plus/minus buttons. The nominal values are shown in the LC display in steps of 0.5 degree C or 1 degree F. The displayed values correspond to a comfort temperature which can deviate from the air outlet temperatures.

The temperature control function is deactivated when the temperature on the driver's side is set to minimum or maximum. Both water valves are closed in the minimum position and opened in the maximum position.

Defrost
The defrost feature has a priority function in air distribution and in the control calculation for heating. The defrost function is activated by means of the defrost button.

At an outside temperature below 10 degree C, the water valves are forced open.

If the outside temperature exceeds 10 degree C, the nominal temperature value for the driver's and passenger's side is increased by 1 degree C. At the same time, the nominal heat exchanger value is increased by at least 30 degree C.

Front mixing air control
During the heating phase, the front passengers can vary the air outlet temperature from the ventilation nozzles by varying the setting of the mixing air control wheel accordingly. The mixing air flaps are adjusted by purely mechanical means with a Bowden cable assembly.

Interior sensor and blower for interior sensor
A forced-ventilated sensor is integrated in the operating unit in order to measure the interior temperature. This sensor is ventilated by a blower installed in the operating unit.

The interior sensor only evaluates temperatures between 10 degree C and 40 degree C.

NOTE: The sensor blower in the operating unit switches on immediately as soon as the load cutout is activated (e.g. doors are opened). The blower is switched off after 16 minutes by the load cutout function.

Auxiliary water pump
An electrically operated auxiliary water pump is installed in order to ensure an adequate water flow rate at low engine speeds. This water pump ensures virtually constant speed-independent water flow through the heat exchanger.

The auxiliary water pump is switched on at:
- Engine temperature > 0 degree C and heat required on driver's and/or passenger's side
or
- defrost ON
or
- residual heat function active
or
- latent heat accumulator switched on
and
- blower stage > 0
and
- control unit OK

The auxiliary water pump is switched off at:
- Engine temperature < 0 degree C
or
- No heat required on driver's or passenger's side
or
- control unit defective