83-0007 Function description
A. General
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- The auxiliary heater is connected to the coolant circuit of the engine. It can be switched on when the vehicle is parked or when driving.
- The auxiliary heater is used to heat the passenger compartment and to defrost the vehicle windows. The engine is also preheated by means of the coolant which ensures reliable starting of the engine even at low outside temperatures.
- The auxiliary heater can only be operated when the heater valve is open.
DBW 2010: With the timer or when the
ignition key is in position 2 or
when driving by means of
the continuous operation
switch.
DBW 2010: With the preselector.
- The heater unit should be operated for approx. 10 minutes per month in summer in order to maintain satisfactory operation of the moving components.
Caution
The auxiliary heater must not be operated in enclosed areas with no exhaust extraction facility even with preselected timing. Switch the auxiliary heater off at fuel stations.
B. Operation
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DBW 2010 heater unit with continuous operation switch or timer
Continuous operation switch
- Position heater valve on hot.
- Switch on heater unit by pressing the continuous operation switch (1).
- The operating indicator lamp (2) comes on and the heater unit starts up.
- Switch off heater unit by pressing the continuous operating switch (1) again.
Timer
Dial illumination
Switching on: Press switch (6) and turn clockwise.
Switching off: Turn switch (6) counter-clockwise
Switching on the auxiliary heater
- Turn the setting handle (5) clockwise back beyond the colored zone (3) and then up to the right hand edge of the colored zone (arrow).
- The operating indicator lamp comes on and
the heater unit starts up after approx.
1 minute.
- The heating period is limited to 60 minutes
Switching off the auxiliary heater
- Turn setting handle (5) anticlockwise up to the end of the colored zone (3). A resistance has to be overcome.
Note
Do not use force when operating the setting handle.
- The operating indicator lamp goes out and the heater unit is switched off automatically.
Setting the preselected time
- Adjust the rotating dial (4) so that the appropriate time of day (e.g. 18.00 hours) aligns with the right hand edge of the colored zone (arrow).
- Turn the setting handle (5) with the tip travelling clockwise beyond the switch-on time of the heater unit (e.g. 10.00 hours). Then turn back to 10.00 hours.
- The heater unit automatically switches on at the set preselected time and the operating indicator lamp comes on.
- The heating period is limited to 60 minutes.
3 Colored zone
4. Rotating dial
5. Setting handle
6. Dial illumination switch
DBW 2012 heater unit with preselector
Setting the time of day
- Set the time by simultaneously pressing button (8) and one of the two buttons (1) or (5).
Display of time set
- If button (8) is pressed, the time of day appears in the display panel (4).
After button (8) is released, the time disappears, or if a preselected time is set, this is displayed for 2 seconds.
Switching the auxiliary heater on and off
- Position heater valve on hot.
- The auxiliary heater can be switched on or off by pressing button (7). When the auxiliary heater is switched on, the green operating indicator lamp (6) comes on.
Setting the preselected time
- Two different preselected times (9) or (10) can be set within 24 hours. The heating period is limited to 60 minutes.
- Tap button (9) or (10).
- The appropriate switch-on time and the preset time number (2) or (3) appears in the display panel. The yellow stand-by indicator lamp (11) comes on. The preselected time can be changed by pressing buttons (1) or (5).
- The display of preselected time disappears after 20 seconds, the preset time number (2) or (3) remains switched on.
- The set preselected time is activated.
1 Putting the time backwards
2 Code for 1st preselected time
3 Code for 2nd preselected time
4 Display panel
5 Putting the time forwards
6 Operating indicator lamp (green)
7 ON/OFF switch for instant heat
8 Time of day
9 2nd preselected time
10 1st preselected time
11 Stand-by indicator lamp (yellow)
C. Method of operation
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- If the auxiliary heater is switched on with the preselector or via the continuous operation switch, the operating indicator lamp comes on when the heater valve is open. The combustion blower, fuel pump and circulation pump start up when the heater valve is open.
- After approx. 15 seconds fuel is sprayed into the combustion chamber via the atomizer nozzle. At the same time the spark generator switches on which ignites the fuel.
- Once combustion has started, the flame monitor switches off the spark generator again. The circulation pump extracts the coolant from the engine and pumps it through the heater unit thus warming the coolant. The heated coolant flows back to the engine again via the vehicle heater.
- When a coolant temperature of approx. 70°C (DBW 2010) or 78°C (DBW 2012) is reached, the control thermostat or temperature sensor takes over the control mode, which keeps the coolant at a constant level by alternately switching the heater unit on and off.
- If the coolant temperature reaches the switch-off temperature of the control thermostat or temperature sensor, the solenoid valve shuts off the fuel supply and the flame goes out.
- The heater unit runs on.
DBW 2010: Runs on for approx. 150 seconds, operating indicator lamp comes on,
combustion blower, fuel pump and circulation pump continue to operate.
DBW 2012: Runs on for approx. 90 seconds (approx. 20 seconds in the case of hazardous
goods transport (GGVS)). Operating indicator lamp comes on, circulation pump
continues to operate.
- If the coolant temperature reaches the switch-on temperature (approx. 63°C) of the control thermostat or temperature sensor, the heater unit starts up again.
- If the auxiliary heater is switched off with the preselector or the continuous operation switch, the heater unit runs on and is then switched off automatically.