General - Webasto Air Top Evo 3900 Workshop Manual

Air Top Evo 3900/5500
9 Repair
9.1

General

This section describes the repair work that may be carried
out on the Air Top 3900/5500 heater after it has been
removed from the vehicle.
Any further dismantling will invalidate the warranty.Only
use the spare parts from the appropriate spare parts kits
for assembling the heater.
9.1.1 Work on stripped down components
IMPORTANT
All sealing elements between the stripped down
components and the seal on the exhaust outlet must
always be discarded and replaced.
9.1.1.1 Cleaning
• Clean all stripped down components with benzene
and then dry them with compressed air.
• Remove all seal residue on the components in full
carefully using a suitable tool.
9.1.1.2 Visual inspection
• Check all components for damage (cracks,
deformation, wear, etc.) and fit new ones if necessary.
• Inspect the plugs and cables for corrosion, loose
contacts, crimping faults, etc. and repair them if
necessary.
• Check plug strips for signs of corrosion and contacts
to ensure they are secure.Repair them if necessary.
9.1.2 Carrying out modifications
The constant development of our heaters is aimed at
optimising them so as to prevent failures and
malfunctions.
Generally it is possible to modify heaters that are already
in use.We can supply the appropriate modification kits for
this purpose.
The following describes modifications that can be carried
out without any great effort during standard repair work:
• Installation of an external temperature sensor for
better temperature control (see 9.1.2.1).
NOTE
9.1.2.1 Installation of an external temperature sensor
General
The Air Top Evo 3900 or Air Top Evo 5500 heater can
control the required temperature perfectly if its
temperature sensor is exposed to the air temperature of
the main area of the vehicle.. In certain circumstances,
this is not always possible using the temperature sensor
integrated in the control unit due to the installation
circumstances.In this case perfect temperature control
can be ensured using an external temperature sensor
fitted in the appropriate area.
Method
1. Select a suitable position for an external temperature
sensor.
• The temperature sensor should not be in the direct
line of hot air and not close to heat sources (for
example the vehicle's own heating system).
• The sensor is to be installed at medium height in the
vehicle cabin on surfaces that are as vertical as
possible.
• The installation site should not be exposed to direct
sunlight.
• Do not install the temperature sensor behind curtains
or the like.
2. Remove the cover and disconnect the terminating
resistor (5, fig. 902) from the control unit (plug X5).
3. Install the external temperature sensor and route the
cable to the heater.
4. Connect the plug on the external temperature to
socket X5 on the control unit and fit the cover.
5. Conduct a trial and check the control properties.
External temperature sensor
9 Repair
NOTE
Cover
901