Terminate heater operation, function

After elapse of the runtime of tmax = 1 h, a status change from "Circuit 15 ON to "circuit 15 OFF", a status change from "circuit 61 ON" to "circuit 61 OFF" or by operating the warm water stationary heater switch (S46/11) in the upper subfield again, then stationary heater (STH) operation of the stationary heater unit is terminated via the warm water auxiliary heating control unit (N33/3).

By operating the lower subfield of the warm water stationary heater switch, the heater booster (ZUH) operation of the stationary heater unit is terminated with status "circuit 15 ON" and "circuit 61 ON" via the warm water auxiliary heating control unit.

The signals of the warm water stationary heater switch are directly read in by the warm water auxiliary heating control unit via a discrete line. The warm water auxiliary heating control unit reads in the signals and then interrupts actuation of the following components needed for the particular heater operation of the stationary heater unit:

 Blower motor (N33/3m1) of STH combustion air blower, for combustion air supply

 Glow pin (N33/3r1), for preheating the combustor with downpipe and for ignition of the fuel

 Metering pump (M46/1), for fuel supply

 Circulation pump (M13/4), for coolant circulation

The actuation of the red light emitting diode (LED) integrated in the warm water stationary heater switch is also directly interrupted via a discrete line. The red LED goes out.

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