OPERATING INSTRUCTIONS
Heater Start-up Sequence:
Upon switching on, an operating indicator light will illuminate.
The combustion air fan, fuel pump and circulation pump start operation. (If fitted and temperature is < 0 °C (< 32 °F)
nozzle preheating is also activated).
After approximately 15 seconds the fuel solenoid valve opens allowing fuel to flow to the nozzle where it is atomized
and sprayed into the combustion chamber. At the same time, a high voltage ignition spark is generated at the
electrode tips simultaneously igniting the fuel air mixture. A photo control device detects a flame in the combustion
chamber and deactivates the ignition system (combustion process is self-sustaining). At this point the heater is
working and producing heat.
The Webasto heater will cycle on and off until:
1. System coolant reaches operating temperature.
2. The Webasto heater is switched off.
3. Time has elapsed on the timer.
4. The vehicle battery voltage drops below 10.5V for 12 volt systems or 20.0V for 24 volt systems.
5. The Webasto heater runs out of fuel.
6. A fault lock out occurs, indicated by the operating indicator light being off during the cool down cycle (as would
happen during an overheat situation.
NOTE:
If the heater is switched on while the engine is at operating temperatures above 140 °F (60 °C) for orange and white
wire thermostat or 155 °F (68 °C) for red and green wire thermostat, only the operation indicator and the coolant
circulation pump will be activated. Depending on the type of thermostat installed, the engine coolant temperature
must fall below 140 °F (60 °C) or 155 °F (68 °C) at the heater before the heater will begin heating operation.
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WEBASTO DBW SERIES HEATERS
