8SERVICING
T
HERMO
90 / 90 S
8-4
8.6.2.1 Fuel Tapping
Fuel tapping must be from the fuel reservoir or from a
separate tank (Fig. 8-3). This separate fuel tapping
avoids an influence on the pressure.
Vehicles with Gasoline Engines
In combination with carburetor equipped or fuel injected
gasoline engines with a return line, the heater's fuel
system integration must be in the return line.
Carburetor equipped gasoline engines without a return
line must have the heater integrated in the fuel supply
between the vehicle's fuel tank and fuel pump.
NOTE:
A fuel supply line can normally be identified by an
installed fuel filter.
If an exhalation vessel is installed in the vehicle's fuel
system, fuel tapping must be upstream of the exhalation
vessel.
For fuel tapping from the supply or return line only the
specific Webasto fuel tap âTâ, e.g. Ident. No. 470910 for 8
mm ID.may be used. The fuel tap must be mounted so
that the air or gas bubbles can escape towards the fuel
tank. Air or gas bubbles may build up in the vehicle fuel
line in case of a leak in the vehicle's carburetor or fuel
pump or when environmental temperatures are higher
than the fuel evaporation temperature.
The fuel tap should not be located in the engine
compartment because the radiation of engine heat may
cause gas bubbles to build up in the fuel lines causing
malfunctions in the combustion operation.
When installing the heater in vehicles with fuel injection
systems, the fuel pumps location within or outside the
fuel tank must be investigated first.
If the fuel pump is fitted inside the fuel tank, the fuel may
be tapped only from the return line ensuring that the
return line is routed almost to the tank floor. If this is not
the case the fuel line may be lengthened.
In case of a fuel pump mounted externally to the tank,
the fuel tap can be located between the fuel tank and the
fuel pump.
Hole Pattern
Fig. 8-3 Webasto Fuel Tank Tap*
* Use fuel tap only on metal fuel tanks
