Starting heater operation, function

P83.70-0216-09

1 Burner housing

2 Heat exchanger

A6m1 Circulating pump

A6m2 Combustion air blower

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A6n1 Stationary heater/control module

N34 Stationary heater timer

Y23 Stationary heater fuel metering pump

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Function prerequisites

 Coolant temperature  20 °C

 Vehicle heater must be set to "max"
(microswitch S46/7 actuated)

 Vehicle blower set to stage "1"

 Vehicle battery must be sufficiently charged

 Stationary heater not in malfunction interlock mode

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Function sequence

1 The green indicator lamp on the stationary heater timer (N34) comes on. Heating operation is started by pressing the button "immediate heating/immediate ventilation" on the stationary heater timer (N34) or by pressing the switch on the associated RF remote control.

2 The combustion air blower (A6m2) and circulating pump (A6m1) start running. The combustion air blower (A6m2) supplies air in the partial load mode at its lowest capacity.

3 Flame monitor (A6r3) checking is started, the flame monitor indicates:

 "cold" = no flame, start operation is continued

 "hot" = flame, start operation is terminated due to defective flame monitor. Malfunction switch-off is accomplished.

4 The glow pin (A6r2) is switched on. The preglow time of approx. 32 s starts.

5 The preglow time has been completed, the fuel metering pump (Y23) starts pumping fuel:

Gasoline version = full load operation, maximum capacity

Diesel version = partial load operation, minimum capacity

6 The fuel and combustion air form a fuel/air mixture in the burner housing (1)

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7 The safety time of approx. 85 s for flame formation starts:

 The fuel/air mixture is ignited by the glow pin (A6r2), the flame monitor (A6r3) monitors the start of combustion.

8 The safety time is completed, the flame monitor (A6r3) indicates:

 "hot" = sufficient flame formation, the glow pin (A6r2)
is switched off.

 "cold" = no flame formation or flame formation insufficient, the fuel metering pump (Y23) is switched off and the start operation is repeated once. If flame formation is still not accomplished after repeating the starting operation, a malfunction switch-off is accomplished.

9 The stabilization time of approx. 20 s for the combustion starts. The fuel metering pump (gasoline version) is switched to partial load operation, the coolant heats up.

10 When the coolant temperature has increased to greater than 30 °C, the heater actuates the stationary heater relay terminal 15/30 (K16). This connects the vehicle blower motor (M2) to circuit 30. The vehicle blower starts running and the passenger compartment warms up.

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