www.webasto.us
13
Webasto Product N.A., Inc.
Air Top Evo 3900/5500
Fuel Supply
6.
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 11.
A sign must be affixed to the fuel tank’s filler neck warning
that the heater must be switched off before refuelling.
6.1
Vehicles with a Carburetor Equipped Engine
The fuel may only be extracted using the special Webasto fuel extractor (see Figure 12) 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 (see Figure 13).
The fuel extractor must be fitted in such a way that any air or gas bubbles are automatically discharged towards the
tank (see Figure 12).
Figure 12. Webasto fuel extractor
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.
Permissible fuel inflow height H
At max. pressure in fuel line
0.00 m (0.00 in.)
0.2 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 max. negative pressure in the
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)
iØ2mm
iØ2mm
iØ2mm
iØ2mm
I2
I2
I1
I1
max.3m
H
S
I2
I1
+
10 m
1.2 m
8.8 m
I2
I2
Figure 11. Fuel supply
a= 6
Ø
8
Ø
10
Ø
12
Ø
0-60°
Ø
5
0-60°
0-60°
0-60°
0-60°
0-60°
From Tank
To Engine
To Fuel Metering Pump