Troubleshooting; Faults; Fault Lock-Out And Heater Lock-Out; Fault Lock-Out Due To Undervoltage Or Overvoltage - Webasto thermo top evo Workshop Manual

Thermo Top Evo
5

Troubleshooting

5.1

Faults

5.1.1 Fault lock-out and heater lock-out

Faults which occur are assigned to various categories:
Fault
1) A fault which occurs has no effect on the current
combustion operation; an fault message is stored.
2) A fault which occurs causes automatic restarting or a
restart; a fault message is stored.
Fault lock-out
3) A fault which occurs in the power supply or in the
control unit results in an immediate heater switch-off
without burn-out. No fault is entered.
4) A fault which occurs results in a heater switch-off (burn-
out) or prevents heater start-up; a fault message is
stored. Restarting requires a switch-off signal and a
repeat switch-on signal.
Permanent heater lock-out due to multiple repetitions of
an fault
5) If a fault from 4) occurs 6 times consecutively without
the full load state being reached, then the heater is
locked out and a fault message is stored.
The lock-out can only be cancelled at the workshop.
If the fault is an undervoltage switch-off due to a weak
battery, then no lock-out occurs.
Overheating lock-out (heater is overheated)
6) The heater overheats and is locked out; a fault message
is stored.
The lock-out can only be cancelled at the workshop.
If a fault lock-out and a subsequent heater lock-out occurs,
then no display occurs on the heater controls. A start-up of
the heater is permitted; a fault is no longer present.
In case of a heater lock-out, the heater is locked out and
cannot be switched on.
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5.1.2 Fault lock-out due to undervoltage or
overvoltage
In case of an undervoltage of 11.5 V for a certain period
(20 sec.), a fault lock-out with a run-on occurs. The specified
undervoltage is software-dependent and is measured at the
control unit input.
In case of an overvoltage of 16.0 V (measured on the
heater) for a certain period (5 sec.), a fault lock-out with
run-on also occurs.

5.1.3 Fault release

After the fault cause is eliminated, the fault release is carried
out by switching the heater off and then on again.
IMPORTANT
A permanent heater lock-out/overheating lock-out can only
be cancelled with the Webasto Thermo Test PC Diagnosis.
The heater faults stored in the fault memory must be read
out and printed with the Webasto Thermo Test PC Diagno-
sis. To delete the heater lock-out without clearing the fault
memory, select the menu command Fault memory/Delete
heater lock-out.
In exceptional cases, the heater lock-out can be cancelled by
disconnecting the power supply of the control unit (e.g. by
removing the fuse F1, 20 A for at least 10 seconds). The
fault must be eliminated beforehand. (See Section 5.3). The
fuse must be pulled within 10 sec. after switching on the
heater.
5.2

General fault symptoms

The following chapter contains a general overview of the
fault symptoms with the heater installed.
IMPORTANT
Troubleshooting work demands precise knowledge of the
structure and theory of operation of the various compo-
nents and must be carried out by trained personnel only.
5 Troubleshooting
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