Webasto Thermo Top V Workshop Manual - Thermo Top V
Thermo Top V
Troubleshooting
503
5.2
Faults
5.2.1 Fault lock-out due to fault on heater
If no flame forms, fuel will be delivered for a maximum of
240 seconds. Then the heater goes into the fault mode and
switches off. The reason for the fault may be faults
described in section 5.1.1.
The fuel supply is shut off immediately if the system over-
heats (temperature limiter is tripped) and the heater goes
into a heater lock-out.
In all cases (except for a defect in the combustion air fan),
the fan is controlled after the fault lock-out to cool down
the heater. Restarting is not possible until the run-on has
been completed.
NOTE
Faults are not indicated by the heater control.
5.2.2 Fault lock-out due to undervoltage or
overvoltage
At a battery voltage of less than approx. 11.5 V, a fault lock-
out with a run-on is carried out. The minimum permissible
voltage is customer-specific (software-dependent) and is
measured at the wiring harness inlet.
In case of an overvoltage of 15 to 17 V (measured at the
heater) for a certain period of time, a fault lock-out with
run-on is also carried out.
Fault release
After the fault cause is eliminated, the fault release is carried
out by switching the heater off and then on again.
Heater lock-out
In case of overheating, a heater lock-out will be initiated by
the heater.
The heater release is carried out as described in section 3.3.
13.
Coolant circuit
Test connection in vehicle coolant circuit as described in installation instructions/
installation suggestion,
bleeding of coolant circuit ensured,
test circulation in coolant circuit,
eliminate kinks and chaffing.
14.
Exhaust system and air intake
system
Intake pipe and exhaust pipe routed as described in installation instructions/instal-
lation suggestion
Make sure lines are not restricted with insulation/clogged
Eliminate existing leaks on intake pipe and exhaust pipe (now CO
2
in intake air)
15.
Vehicle fan
Test switching signal on relay K3 (Pin 86) as described in installation instructions/
installation suggestion
Watch coolant temperature (K3 switches at 50 °C)
Test flap position of vehicle heater (air conditioning set to HI)
16.
Control unit/heater locked
Unlock as described in section 5.2.2 and installation instructions/installation sug-
gestion
17.
Control unit (fault memory)
Read out fault memory with Webasto Thermo Test PC Diagnosis, then print out
and clear fault memory.
Include fault log when sending heater to Webasto.
No. System
Component
Test/Measure/Parameter
Fig. 502 Overview of functional analysis of heater and components
Visit www.butlertechnik.com for more technical information and downloads.
www.butlertechnik.com