Webasto Thermo Top C-B Installation Instructions Manual page 43

Thermo Top C / Thermo Top E
from tank
to metering pump
Fig. 8: Webasto fuel pickup
When installing the heater in a vehicle with fuel injection system, it is
therefore important to establish whether the fuel pump is located inside
or outside the tank.
If the fuel pump is located inside the tank, fuel can only be withdrawn
from the return line. In this case, it must be ensured that the return line
continues almost to the bottom of the tank. The return line must be
extended if necessary.
to engine
8.4. Fuel lines
NOTE:
The hose clips must be tightened with a torque of 1.0 + 0.4 Nm.
Leaking fuel must be removed before starting the engine or heater.
Only steel, copper and plastic lines of plasticized, light and temperature-
stabilized PA 11 or PA 12 (e.g. Mecanyl RWTL) in accordance with
DIN 73378 may be used for the fuel lines.
IMPORTANT:
If PME (vegetable oil methyl ester) is used as fuel, care must be taken
to ensure that the fuel lines and fuel filter are resistant to PME.
Since the lines normally cannot be routed with a constant uphill gradient,
the inside diameter must not be allowed to exceed a certain size. Air or
gas bubbles will accumulate in lines with an inside diameter of more
than 4 mm and cause malfunctions if the lines sag or run downwards.
The diameters specified in Fig. 7 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
chippings and high temperatures (exhaust line).
Fuel connection
41