Starting heater operation, function - GF83.70-G-2000A

MODEL 463 as of 1.6.94 with CODE (H12) Stationary heater Webasto Tele Thermo Top S 

Fig 1: Starting Heater Operation Function Diagram

Courtesy of MERCEDES-BENZ USA

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

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. A6n1
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)
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.

	Malfunction shut-off		GF83.70-G-3037A
	Controlled heater operation		GF83.70-G-2004A
	Interruption of heater operation		GF83.70-G-2005A
	Termination of heater operation		GF83.70-G-2002A
	Stationary heater timer		GF83.70-G-4007A
	Combustion air blower		GF83.70-P-4004A
	Circulating pump		GF83.70-P-4003A
	Flame monitor		GF83.70-P-4006A
	Burner housing		GF83.70-P-4000A
	Glow pin		GF83.70-P-4005A
	Fuel metering pump		GF83.70-P-4008A
	Radio frequency remote control		GF83.70-G-4049A