Technical data

DBW 2010 / 2012 / 2020 / 2022 / 300 / 350 8 Service Tasks
803
8.6 The Visual Examination or the
Assembly Instructions
8.6.1 The connection to the cooling system of
the vehicle
The heating system must be installed at a place that is as
deep as possible in order to ensure that the evacuation of
air from the heating device and circulation pump will
occur by itself. This feature is valid for the circulation
pump that does not suck by itself.
The heating device must be connected to the cooling
system of the vehicle according to the Figure 802. The
amount of the cooling liquid available in the circuit must
be at least 10 liters.
Excessive pressure valves, of which the sole opening
pressure is at least 0.4 bar and maximum 2.0 bar, can be
used in the cooling system of the vehicle or in a separate
heating circuit.
As a matter of principle, the cooling liquid hoses delivered
by Webasto must be used. If this is not the case, the
hoses must comply at least with DIN 73411 standard.
The hoses must be laid without any break – so that the
evacuation of air can be carried out without problems –
and as far as possible in climbing manner. The hose
connections must be accomplished securely with hose
clamps.
WARNING
Attention must be paid to the tightening torque of the
hose clamps that will be used.
The air of the heating device must be carefully evacuated
prior to the commissioning or after the cooling liquid has
been replaced. The heating device and the pipes must be
installed in such way to ensure the accomplishment of
static air evacuation.
Insufficient air evacuation could lead to defects during the
course of work as a result of excessive heating.
The fact that the circulation pump works almost entirely
silent means that there are no problems with regard to
the evacuation of air.
In the case that there is no cooling water while the
circulation pump is working or when the pump wheel is
blocked, the circulation pump will be automatically shut
off 15 seconds after the start and can only be re-operated
after 2 minutes.
8.6.2 The connection to the fuel system of the
vehicle
The fuel will be supplied from the fuel tank of the vehicle
or from a separate fuel tank.
8.6.2.1 The fuel lines
The fuel pipes must be laid as far as possible in a
climbing inclination in order to prevent the seizure of air.
The connections in a line must be secured by hose
clamps if mechanical screwed connection is not used.
As a matter of principle, the hoses delivered or offered by
Webasto must be used if fuel hoses are used. If this is
not the case, the fuel hoses must comply at least with
DIN 73379 standard. The fuel hoses should not break or
be twisted and must be fixed at a distance of 25 cm with
clamps. Subject to the condition of compliance with the
proper connection technique regarding the fuel line, steel,
cupper and soft plastic pipes conforming to DIN 73378
resistant to light and heat and manufactured from PA11
or PA12 (for instance, Mecanyl RWTL) can be used.
Attention must be paid to the following issues while laying
the fuel lines:
• The lines must be protected against the effect of heat
DANGER
In case of excessive heating of the heating device, the
outer coating of the heating device can reach the
inflammation temperature of diesel fuel!
• The lines must be protected from the impacts caused
by stone.
• The dripping or evaporating fuel should not gather
and should not be exposed to inflammation resulting
from the contact with hot parts or electrical
mechanisms.