GF83.70-P-3058SX Activate Preprogrammed Heater, Function

GF83.70-P-3058SX Activate Preprogrammed Heater, Function
- with CODE (228) Stationary heater

Component Identification:

Departure time programming
The departure time is configured and activated in the COMAND controller unit with the aid of the central operating unit. The departure time menu is called up in the COMAND controller unit via the central operating unit at circuit 15R On and the departure time is then entered. This is shown in the COMAND display. Up to 3 departure times can be stored. Following selection, the departure time must then also be activated. Activation is indicated by the yellow indicator lamp in the STH button. The selected departure time is stored in the instrument cluster.

Model 216 and model 221 as of 1.6.06:
The departure time can also be activated or changed using the stationary heater transmitter. On model 221, the telephone antenna receives the signal and forwards it to the antenna splitter on the stationary heater receiver.

On model 216, the signal is received by the stationary heater antenna and forwarded to the stationary heater receiver. The stationary heater receiver transmits each signal to the STH control unit. The stationary heater transmitter receives the current stationary heater status per radio. The current configuration is filed in the COMAND controller unit and shown in the COMAND display. Activation is indicated by the yellow indicator lamp in the STH button. The selected departure time is stored in the instrument cluster.

Function requirements
^ C. 15C OFF
^ Activated departure time
^ Sufficient remaining quantity of fuel in tank

The departure times currently stored in the instrument cluster are suppressed if the heater has been manually switched on in the meantime.

Function
One hour prior to the entered departure time the instrument cluster initiates a query to the AAC [KLA] control unit as to the actual required starting time. The AAC [KLA] control unit then determines the ideal starting time based on the currently recorded outdoor and indoor temperatures. This is transmitted to the instrument cluster and the system returns to bus idle.
At the determined starting time, the instrument cluster then sends the switch-on command via the central gateway control unit to the STH control unit. This then forwards the request to the AAC [KLA] control unit. The AAC [KLA] control unit determines the current interior and outside temperature. Depending on the determined values and the last setting of the AAC [KLA] control unit, the AAC [KLA] control unit makes a decision either for heating or ventilation and then transmits the decision to the STH control unit.

If the decision is for heating, a query on the status of all components involved in the heater operation is conducted and a self-test is performed if required. The heater operation is not started in the event of a relevant fault. However, the stationary ventilation function is always performed, irrespective of the result.

Heating decision
The fuel metering pump is actuated to supply fuel and the heater unit starts heater operation.
To enable the interior to be heated up faster, the heater unit regulates the flow of coolant depending on the temperature between the small and large coolant circuit via the STH switchover valve.
The coolant circulation pump ensures that the temperature- controlled coolant is circulated in the coolant circuit. When the temperature is at a sufficient level, the AAC [KLA] control unit actuates the blower motor via the blower regulator.

Ventilation decision
During stationary ventilation only the blower is actuated in the vehicle.
The AAC [KLA] control unit actuates the blower motor via the blower regulator.

Depending on the interior temperature, a switchover from stationary heating to stationary ventilation and vice versa can be made.

Status indicator
The red indicator lamp in the STH button indicates stationary heating, and the blue lamp indicates stationary ventilation.