Heater Smokes; Heater Cannot Be Switched Off - Webasto DBW 2010 Service And Repair Manual

TROUBLESHOOTING
5.3.7 H S
EATER MOKES
Does heater smoke more
than 20 seconds?
YES
Did other unsuccessful
start attempts precede?
Any accumulated fuel in
the combustion chamber
must be allowed to burn
off; Does heater
continue to smoke?
Open burner, remove
combustion chamber;
are there coke deposits
visible in the combustion
chamber?
Clean combustion
chamber
5.3.8 H C
EATER ANNOT
Is there current through
the switch or timer
when switched OFF?
Switch or timer defective
Webasto Product N.A., Inc.
NO
Does heater smoke
during operation (also
in waves)?
Are ignition electrodes
set correctly according
to setting gauge?
Replace fuel nozzle
Flow through fuel nozzle
insufficient, - replace;
does heater continue to
smoke?
Replace fuel nozzle
B S O
E WITCHED FF
Do exhaust gases still
emit from the exhaust
pipe after switching
OFF?
Does control thermostat
open when the upper
set point is reached?
No positive voltage on
the fuel solenoid valve?
Does fuel solenoid valve
close (stuck open)?
DBW 2010/2020/300 COOLANT HEATERS
Set ignition electrodes
correctly with setting
gauge
Does heater continue to
run more than 180 sec.
after switching OFF?
Electronic control unit
defective
Control thermostat
defective?
Electronic control unit
defective
Solenoid valve defective
30
Does heater smoke
after switching OFF?
Fuel solenoid valve
piston is leaky
www.techwebasto.com