8SERVICING
T
HERMO
90 / 90 S
8-6
8.6.3.2 Installation and Attachment
The fuel dosing pump is to be attached with anti-vibration
mounts. The installation location is limited according to
Fig. 8-5 to ensure sufficient self-bleeding capability. Due
to the danger of corrosion, the plug connection between
fuel dosing pump and fuel dosing pump cable loom may
only be fitted with Webasto original spare parts.
8.6.4 Fuel Filter
If there is the probability of contaminated fuel, only the
Webasto filter, part number 487171, may be used. The
use of fuel filters not designed for Webasto heater fuel
systems may cause a vapor lock or interfere with the
proper delivery of fuel.
The fuel filter can be installed anywhere between the
vertical and horizontal positions, but must be installed in
the direction of flow.
8.6.5 Combustion Air Supply
Combustion air must under no circumstances be
extracted from rooms with persons. The combustion air
inlet must not point towards the forward direction of
motion. It must be located so that no clogging by
contamination, impact of snow, or intake of splash water
is possible.
The combustion air intake line (inner diameter at least
30 mm or 1 3/16 in.) may have a length from 0.5 m to 5
m (18 in. to 16 ft.) with several bends totaling no more
than 360°. Smallest bending radius is 45 mm (1 3/4 in.).
The combustion air inlet must not be located above the
exhaust outlet.
NOTE:
The combustion air intake line is to be routed in a
downward direction. If this is not possible, a water drain
hole (4 mm or 5/32 in.dia.) must be provided at the
lowest point.
If the heater is located near the fuel tank in a common
installation compartment, combustion air must be taken
in from, and the exhaust routed to, the exterior.
The feed-through openings must be splash waterproof.
If the heater is located in a closed installation box, a vent
port of at least 6 cm2 (2 3/8 in2) is required. If the
temperature in the installation box exceeds the permitted
ambient temperature of the heater (see Technical Data),
the vent port must be enlarged.
8.6.6 Exhaust Line
The exhaust line (inner diameter 38 mm or 1.5 in.) may
have a length from 0.5 m to 5 m (18 in. to 16 ft.) and be
routed with several bends totaling no more than 360°.
Smallest bending radius is 85 mm (3 3/8 in.).
The exhaust muffler is mandatory and to be mounted
near the heater.
In order to ensure the angle of 90° ± 10°, an attachment
is required no further than 150 mm (6 in.) away
measured from the exhaust pipe end.
The exhaust pipe outlet opening must not point in the
direction of motion (see Fig. 8-6).
The exhaust pipe outlet opening must be located so as
not to allow clogging by snow or mud.
Rigid exhaust-line pipes can be made of unalloyed or
alloyed steel, but must have a minimum wall thickness of
1.0 mm (1/32 in.). Flexible exhaust pipes must be made
only of alloyed steel. The exhaust pipe is secured to the
air heater with a clamp. For further requirements, consult
Webasto Thermosystems.
Fig. 8-6 Exhaust Outlet, Direction of Flow
