8.6.2 Fuel Supply
8.6.2.1 Fuel Tapping
Vehicles with a Diesel Engine
Fig. 801 Fuel Supply
802
8 Servicing
Air Top 2000 S
iØ2mm
iØ2mm
iØ2mm
iØ2mm
I
2
I
2
I
1
I
1
max. 3m (9.8 ft.)
H
S
I
2
I
1
+
≤ 10 m (32.8 ft.)
≤ 1.2 m (3.9 ft.)
≤ 8.8 m (28.8 ft.)
I
1
I
2
Vehicles with an Injection Engine
When installing the heater in a vehicle with fuel injection
systems, 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 a Webasto fuel
tee fitting 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, a Webasto fuel standpipe
(see Figs. 802, 803 and 804) may be used.
If the fuel pump is installed outside the tank, the fuel
connection may also be made between the tank and
fuel pump, again using only the Webasto fuel tee fitting.
Vehicles with a Carburetor Engine
The fuel may only be extracted on cars using a special
Webasto fuel tee fitting as close to the tank as possible.
The connection 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 tee must be fitted in such a way that any air or
gas bubbles are automatically discharged towards the
tank.
The fuel tee 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.
The fuel is taken from the vehicle fuel tank or from a
separate fuel tank. The values for maximum pressure
at the fuel extraction point are shown in Fig. 801.
The fuel must be taken from the vehicle fuel tank or
from a separate tank (Figs. 802, 803 and 804). This
separate fuel pickup precludes any effect of pressure.
Permissible fuel inflow
height H
At maximum pressure in
fuel line
0.00 m (0.00 in.) 0.20 bar (2.9 PSI)
1.00 m (39.4 in.) 0.11 bar (1.6 PSI)
2.00 m (78.7 in.) 0.03 bar (0.44 PSI)
Maximum fuel intake
height S
At maximum negative
pressure in fuel tank
0.00 m (0.00 in.) -0.10 bar (-1.45 PSI)
0.50 m (19.7 in.) -0.06 bar (-0.87 PSI)
1.00 m (39.4 in.) -0.02 bar (-0.29 PSI)
