Webasto Air Top Evo 3900 Workshop Manual page 36

8 Servicing work
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 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, 803 or 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).
Hole pattern
Only use a tank extractor with metal fuel tanks
Fig. 802 Webasto fuel extractor
804
NOTE
Air Top Evo 3900/5500
Plastic tank
Sealing ring
Fig. 803 Fuel extractor from the plastic tank (extraction
through tank drain screw)
Fuel extractor
Tank fittings
The fitting must be made from metal!
Fig. 804 Fuel extractor from the plastic tank
(Pickup via tank fitting)
Sealing ring
NOTE