Technical data

Servicing work Air Top 2000 ST
802
IMPORTANT
In vehicles used to transport people, the air outlet opening
is to be installed in such a way that it is at least 20 cm away
from all body parts.
The heaters check the internal temperature rise
automatically each time they are switched on. If this is above
the specified limits, the start is cancelled and error messages
F10 is displayed. To ensure that the heater functions stably,
the flow resistance of the connected hot air system must be
reduced.
If a filter is used for the hot air, it must have the following
properties:
• The current of air must not carry any inflammable and/
or harmful fibres or particles into the heater or the
interior of the vehicle.
• The filter material must be able to withstand
temperatures of at least 60 °C
• The filter must be resistant to all the substances that
may be drawn in with the hot air (for example moisture,
salt, fuel vapours, etc.).
• The resistance of the filter must be taken into
consideration when designing the hot air system
8.6.2 Fuel supply
The fuel is taken from the vehicle fuel tank or from a
separate fuel tank. The values for the maximum pressure at
the fuel extraction point are shown in Figure Fig. 801.
8.6.2.1 Fuel extraction
Vehicles with diesel engines
The fuel must be taken from the vehicle fuel tank or from a
separate tank (see Fig. 802, Fig. 803 or Fig. 804). This
separate fuel pickup precludes any effect of pressure.
Vehicles with carburettor engines
The fuel may only be extracted on cars using the special
Webasto fuel extractor (for example Part No. 470 910) as
close to the tank as possible. The connect may be made in
either the supply or return line, in which case the return line
must lead almost to the base of the tank. If this is not the
case the return line may be extended.
The fuel extractor must be fitted in such a way that any air
or gas bubbles are automatically discharged towards the
tank.
The fuel extractor should not be located near the engine, as
gas bubbles may form in the lines on account of heat
radiated from the engine. This may cause problems during
combustion.
Vehicles with injection engines
When installing the heater in a vehicle with fuel injection
system, it is important to establish whether the vehicles fuel
pump is located inside or outside the tank.
If the fuel pump is located inside the tank, fuel can only be
extracted from the return line using the Webasto fuel
extractor (for example Part No. 470 910), in which case it
must be ensured that the return line continues almost to the
bottom of the tank. If this is not the case Webasto fuel
extractor (see Fig. 802, Fig. 803 or Fig. 804) may be used.
If the fuel pump is installed outside the tank, the fuel
connection may also be made between the tank and the
fuel pump, again using only the Webasto fuel extractor (for
example Part No. 470 910).
Permissible fuel inflow
height H [m]
At max. perm. pressure
[bar] in fuel line
0.00 0.20
1.00 0.11
2.00 0.03
Maximum fuel intake
height S [m]
At max. perm. negative
pressure [bar] in the fuel
tank
0.00 -0.10
0.50 -0.06
1.00 -0.02