GF83.70-D-2002HZ Terminate Heater Operation, Function

GF83.70-D-2002HZ Terminate Heater Operation, Function
MODEL 906.111 /113 /131 /133 /135 /153 /155 /211 /213 /231 /233 /235 /253 /255 /611 /613 /631 /633 /635 /637 /653 /655 /657 /711 /713 /731 /733 /735
- with CODE (HZ9) Heater booster, diesel
- Heater booster (ZUH)

MODEL 906.611 /613 /631 /633 /635 /637 /653 /655 /657 /711 /713 /731 /733 /735
- with CODE (HZ5) 10 kW warm water auxiliary heater with timer
- Heater booster (ZUH)

On vehicles with code (HZ9) Heater booster, diesel, the heater operation of the heater booster heater unit is terminated after a status change from "circuit 61 ON" to "circuit 61 OFF" or when the stationary heater switch (S46/10) in the upper subfield is operated again while the engine is running with "circuit 61 ON"; this is done via the warm water auxiliary heater 2 control unit (N33/2). The signal of the stationary heater switch is directly read in by the warm water auxiliary heater 2 control unit via a discrete line.

The stationary heater switch has a "Memory function" (automatic heater operation activation of the heater booster heater unit). The "Memory function" remains active (also in the event of a status change of circuit 15 and circuit 61) until it is deactivated again by operating the stationary heater switch in the upper subfield.

On vehicles with code (HZ5) 10 kW warm water auxiliary heater with timer, heater operation of the heater booster heater unit is terminated after a status change from "circuit 61 ON" to "circuit 61 OFF", or when the warm water stationary heater switch (S46/11) in the lower subfield is operated again while the engine is running with "circuit 61 ON". The signal of the warm water stationary heater switch is directly read in by the warm water auxiliary heating control unit (N33/3) via a discrete line and then forwarded to the warm water auxiliary heater 2 control unit.

The warm water stationary heater switch has a "Memory function" (automatic heater operation activation of the heater booster heater unit). The "Memory function" remains active (also in the event of a status change of circuit 15 and circuit 61) until it is deactivated again by operating the warm water stationary heater switch in the upper subfield.

The warm water auxiliary heater 2 control unit reads in the signal directly or via the warm water auxiliary heating control unit and then interrupts actuation of the following components needed for the heater operation of the heater booster heater unit:
- Blower motor (N33/2m1) of the ZUH combustion air blower, for combustion air supply
- Glow pin (N33/2r1), for preheating the burner housing and for ignition of the fuel
- Metering pump (M46/4), for fuel supply
- Circulation pump (M13/4), for coolant circulation

On vehicles with code (HZ9) Heater booster, diesel, actuation of the red light emitting diode (LED) integrated in the stationary heater switch is also interrupted directly by the warm water auxiliary heater 2 control unit via a discrete line.
On vehicles with code (HZ5) 10 kW warm water auxiliary heater with timer, actuation of the red light emitting diode (LED) integrated in the warm water stationary heater switch is interrupted by the warm water auxiliary heater 2 control unit via the warm water auxiliary heating control unit.

After heater operation has been shut off, the heater booster heater unit switches to power-down mode. In power-down mode, the warm water auxiliary heater 2 control unit actuates the blower motor of the ZUH combustion air blower and the circulation pump again in order to cool off the combustor with downpipe of the heater booster heater unit through the generated air suction and the heat exchanger of the heater booster heater unit through the coolant flowing by. The warm water auxiliary heater 2 control unit places the message "ZHZ_EIN (heater booster switched on)" on the Controller Area Network bus class B (interior) (CAN-B) until the power-down mode has been terminated.