Webasto Thermo Top Z

Fuel system integration (additional heater only) Thermo Top Z / Thermo Top C
40
The fuel extractor should not be located near the engine, as gas bubbles
may form in the lines on account of heat radiated from the engine. This
may cause problems during combustion.
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 extracted from
the return line. In this case it must be ensured that the return line
continues almost to the bottom of the tank. If this is not the case the
return line may be extended.
8.2. Fuel lines
NOTE:
The hose clips must be tightened with a torque of 1.0 + 0.4 Nm.
Leaked fuel must be removed before the engine or heater is started.
Only steel, copper and plastic lines of plasticised, light and temperature-
stabilized PA 11 or PA 12 (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 Figure 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
road chippings and high temperatures (exhaust line).
Fig. 8: Webasto fuel extractor
to metering pump
to engine
from tank
TZea_02_gb_e.fm Seite 40 Montag, 3. Februar 2003 2:09 14