Technical data

Servicing work Air Top 2000 ST
804
8.6.2.2 Fuel lines
Only steel, copper and plastic lines of plasticised, light and
temperature-stabilised PA11 or PA12 (e.g. Mecanyl RWTL)
pursuant to DIN 73378 may be used for the fuel lines. Since
the lines normally cannot be routed with a constant rising
gradient, the internal diameter must not be allowed to
exceed a certain size. Air or gas bubbles will accumulate in
lines with an internal diameter of more than 4 mm and
these will cause malfunctions if the lines sag or are routed
downwards. The diameters specified in Fig. 801 will ensure
that bubbles do not form.
The lines should not be routed downwards from the
metering pump to the heater.
Unsupported fuel lines must be secured to prevent them
sagging. They must be installed in such a way that they
cannot be damaged by flying road chippings and high
temperatures (exhaust line).
The fuel lines must be secure at the connections using hose
clips to prevent their slipping.
Connecting two pipes with a hose
The correct procedure for connecting fuel lines with hosing
is shown in Fig. 805.
Fig. 805 Pipe/hose connections
8.6.3 Metering pump
The metering pump is a combined delivery, metering and
shutoff system and is subject to specific installation criteria
(Fig. 801, Fig. 805 and Fig. 806).
8.6.3.1 Installation location
It is advisable to install the metering pump in a cool place.
The maximum ambient temperature must not exceed
+20 °C at any time during operation.
The metering pump and fuel lines must not be installed
within range of the radiated heat from hot vehicle parts.
A heat shield must be used if necessary.
8.6.3.2 Installation and attachment
The metering pump must be secured with a vibration-
damping mounting. Its installation position is limited as
shown in Fig. 806 in order to ensure effective auto-
bleeding. As a result of the risk of corrosion, only genuine
Webasto parts may be used for the plug connections
between the metering pump and the metering pump wiring
harness.
8.6.4 Fuel filter
Only a Webasto filter, ident. no. 487 171, is allowed to be
used if the fuel is expected to be contaminated. Install
vertically if possible, however at least horizontally (check
flow direction).
Fig. 808 Fuel filter
Correct
Wrong
Clip
Bubble
Fig. 806 Metering pump DP 2 with damper, installation
position
Fig. 807 Metering pump DP 30.2, installation position
Air Top 2000 ST 12 V - petrol
ideally
15° - 90°
Installation
position
damper
Metering
pump
Air Top 2000 ST
12 V and 24 V - diesel
Installation
position
damper
Horizontal installation
A
ø 5
0 - 90°