Technical data

Air Top 2000 ST Repair
901
9Repair
9.1 General
This section describes the repair work that may be carried
out on the Air Top 2000 ST 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 compo-
nents and the seal on the exhaust outlet must always be dis-
carded 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 care-
fully 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 con-
tacts, 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
NOTE
The constant development of our heaters is aimed at opti-
mising 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).
9.1.2.1 Installation of an external temperature sensor
General
The heater optimally regulates the desired temperature
when its temperature sensor is loaded with the air temper-
ature of the area mainly occupied. In certain circumstances,
this is not always possible using the temperature sensor
integrated in the control unit due to the installation circum-
stances (mixing in of fresh air). In this case perfect tempera-
ture 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.
NOTE
• 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 ve-
hicle cabin on surfaces that are as vertical as possible.
• The installation site should not be exposed to direct sun-
light.
• Do not install the temperature sensor behind curtains or
the like.
2. Install the external temperature sensor and route the ca-
ble to the heater controller.
3. Cut the terminating resistor off the wiring harness.
4. Crimp the connector X8 for external temperature sensor
onto the end of the cable.
5. Connect the connector of the external temperature sen-
sor to the connector X8 of the wiring harness.
6. Conduct a trial and check the control properties.
Fig. 901 Installation of an external temperature sensor
Connector X8 for exter-
nal temperature sensor
External temperature sensor
Terminating resistor