Fig. 801 Fuel Supply - Webasto Air Top Evo 3900 Workshop Manual

8 Servicing work
The heater can be used with grills on the air inlet and outlet
side if it is used in an air circulation system. Do not short cir-
cuit the current of hot air.
Minimum internal diameter of the main section of hot air
line:
80 mm for the Air Top Evo 3900
90 mm for the Air Top Evo 5500
The hot air hose must be secured at its connection points.
IMPORTANT
In vehicles used to transport people, the air outlet opening
is to be directed in such a way that it is at least 20 cm away
from all body parts.
The heaters check the internal temperature rise automatical-
ly each time they are switched on. If this is above the speci-
fied 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 re-
duced.
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 inte-
rior of the vehicle.
• The filter material must be able to withstand tempera-
tures 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 consider-
ation when designing the hot air system
8.6.2 Fuel supply
The fuel is taken from the vehicle fuel tank or from a sepa-
rate fuel tank. The values for the maximum pressure at the
fuel extraction point are shown in Figure Fig. 801.
802
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Air Top Evo 3900/5500
Permissible fuel inflow
height
H [m]
0.00
1.00
2.00
Maximum fuel intake
height
S [m]
0.00
0.50
1.00
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 sepa-
rate fuel pickup precludes any effect of pressure.
i Ø 2 mm
i Ø 2 mm
I
2
≤ 10 m
l + l
1 2
≤ 1.2 m
l
1
≤ 8.8 m
l
2
Fig. 801 Fuel supply
At max. perm. pressure
[bar]
in fuel line
0.20
0.11
0.03
At max. perm. negative
pressure [bar] in the fuel
tank
-0.10
-0.06
-0.02
max. 3 m
I
2
i Ø 2 mm
I
1
I
1
H
S