Troubleshooting; General Failure Symptoms - Webasto Air Top 3500 Workshop Manual

Air Top 3500/5000
5

Troubleshooting

5.1 General
This section describes the troubleshooting for the heater
Air Top 3500 and Air Top 5000.
After heater malfunction an error code is output to the
display of the combination or standard timer. When
equipped with a control element the operating indicator
light will flash. The heater may also be checked with a
personal computer (refer to Operating Instructions PC
Heater Fault Diagnosis).
CAUTION
Troubleshooting requires profound knowledge about
components and their theory of operation and may only be
performed by trained personnel. In case of doubt
functional interrelations may be derived from Sections
2 and 3.
For ADR operation only
When applying electrical power with the control element
still set to "on", e.g. by closing the battery switch, as well
as after a ADR switch-off, the control unit will go in error
lockout. For re-activation the control element must be
momentarily switched off and on again or the instant heat
switch on the combination timer be operated.
Symptom
Heater does not switch off
automatically
Heater develops black smoke
NOTE
Probable Cause
No combustion after start and
restart
Flame-out during operation
Heater overheats
Operating indicator light flashes
Vehicle electrical system power
supply underpowered
Combustion air and/or exhaust
ducting obstructed
Fig. 501 General Failure Symptoms
CAUTION
Troubleshooting is normally limited to the isolation of
defective components. The following possible causes for
trouble have not been taken into consideration and must
always be excluded as a possible cause or reason for
malfunctions:
• corrosion on connectors
• loose contacts on connectors
• wrong crimping on connectors
• corrosion on wiring and fuses
• corrosion on battery terminals
For checking individual components the electrical
connectors on the control unit must be disconnected.
After any fault correction a functional checkout in the
vehicle has to be performed.
5.2

General Failure Symptoms

The following table (Fig. 501) lists possible failure
symptoms of general nature.
Remedy
Switch off heater momentarily and
switch on once again
Switch off heater momentarily and
switch on once again
Check heating air ducting for
obstructions, allow heater to cool
down,
switch off heater momentarily and
switch on once again
Charge vehicle battery
Switch off heater momentarily and
switch on once again
Check combustion air and exhaust
ducting for obstructions
5 Troubleshooting
501