GF83.70-P-3054E Flame Failure/Flame Monitor Faulty During Heater Operation, Function

GF83.70-P-3054E Flame Failure/flame Monitor Faulty During Heater Operation, Function
- with CODE (228) Stationary heater [models 203 up to 23.4.04, 209.3 up to 31.5.04, 215 as of 1.6.00 up to 31.8.02, 220 as of 1.6.00 up to 31.8.02, 230.4 up to 08]

Component Identification:

Function sequence
1. At a coolant temperature of greater than 65 °C and less than 77 °C the STH heater unit (except model 220) or the STH or HB [ZUH] heater unit (model 220) operates in partial load or full-load mode, depending on the heat requirement.

2. The STH fuel metering pump or the STH or HB [ZUH] fuel metering pump (Y23) and the combustion air blower (A6m2) operate correspondingly at low or maximum output and rotational speed. The circulation pump (A6m1) delivers the coolant via the heat exchanger (2) and the heating and cooling circuits. The blower motor feeds preheated air into the interior.

3. The glow pin unit flame monitor (A6r4) constantly monitors the combustion in the burner housing (1).

4. If the glow pin unit flame monitor (A6r4) signals:
^ "cold" = flame-out due to no or inadequate fuel or combustion air supply
or
^ "cold" = defect in glow pin of glow pin unit flame monitor (A6r4), the STH control unit or the STH or HB [ZUH] control unit (A6n1) initiates a start attempt for approx. 85 s for repeated flame formation and thus for continuing the combustion. The STH fuel metering pump or the STH or HB [ZUH] fuel metering pump (Y23) and the combustion air blower (A6m2) operate at their lowest output and rotational speed. The glow pin of the glow pin unit flame monitor (A6r4) is switched on and resumes its function.

5. At the end of the start attempt lasting approx. 85 s, the glow pin is switched off. If the glow pin unit flame monitor (A6r4) signals:
^ "hot" = repeated flame formation, then combustion is continued. The STH fuel metering pump or the STH or HB [ZUH] fuel metering pump (Y23) and the combustion air blower (A6m2) adapt their output and rotational speed to the heat requirement again. \
^ "cold" = no flame formation, then the STH control unit or the STH or HB [ZUH] control unit (A6n1) trigger the heater unit fault run-on period for approx. 120 s with subsequent fault shutoff. The STH fuel metering pump or the STH or HB [ZUH] fuel metering pump (Y23) is switched off and the control and operating unit (N18, N22 or N22/7) is actuated via CAN-B (CAN-B) with the signal "Blower off".

The control and operating unit (N18, N22 or N22/7) switches the blower motor off and switches from stationary heating mode to normal operating mode.
At the end of the fault run-on period, the combustion air blower (A6m2) and the circulation pump (A6m1) are switched off. The indicator lamp in the STH switch (N72s12 or S46) goes out. Malfunction shutoff is present.

For starting up again, the STH heater unit (except model 220) or the STH or HB [ZUH] heater unit (model 220) must be switched off and on again with the STH switch (N72s12 or S46) after eliminating the cause of the malfunction.