Fig. 801; Fuel System - Webasto Air Top Evo 40 Workshop Manual

Service Work
air outlet side if it is used in an air circulation system. A short
circuit of the cold and hot air flow must be avoided.
Minimum inside diameter of main branch of hot air line:
80 mm for Air Top Evo 40
90 mm for Air Top Evo 55
The cold and hot air hoses must be secured at the connec-
tions.
IMPORTANT
In vehicles in which people are transported, the air outlet
opening must be aligned so that a minimum spacing of
20 cm to the body parts is maintained.
The heater automatically checks the internal temperature in-
crease each time it is switched on. If this is above the speci-
fied limits, the start is cancelled and error messages F10 is
displayed. To enable stable heater operation, the flow resist-
ance of the connected cold and hot air system must be re-
duced.
If a filter is used for the cold 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 interior
of the vehicle.
• The filter material must have at least a temperature resist-
ance of 60 °C.
• The filter material must be resistant to all substances
which can be drawn in with the cold air (for example
moisture, salt, fuel vapours, etc.).
• The resistance of the filter must be taken into account
when designing the cold and hot air circuit.
802
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Air Top Evo 40 / Air Top Evo 55

8.6.2 Fuel system

Requirements for the fuel system are contained in the Air Top
Evo 40 / Air Top Evo 55 installation instructions.
The fuel is taken from the vehicle fuel tank, the vehicle fuel
line or a separate fuel tank.
8.6.2.1 Fuel pump
The fuel pump is a combined pumping, metering and shut-off
system and is subject to certain installation criteria (for instal-
lation positions, see Fig. 801).
The Air Top Evo 40 / Air Top Evo 55 heaters may only be op-
erated with the DP 42 fuel pump.

Fig. 801

Installation position of fuel pump DP 42
Installation location
The fuel pump may not be installed in the radiation area of
hot vehicle parts. A heat shield must be provided if necessary.
The preferred installation space is near the fuel tank.
For the permissible ambient temperature, see Chapter 4,
"Technical Data"
Installation and attachment
The fuel pump must be fastened with a vibration-damping
suspension. The installation position is restricted as shown in
Fig. 801 (maximum fuel pump tilt angle, axial installation po-
sition of fuel pump).
The arrow indicates the direction of fuel flow.