Fig. 801 Fuel Line Lengths, Inside Diameter And Height Differences (Fuel Tank, Heater) To Fuel Pump; Fuel Supply - Webasto Air Top 2000 STC Workshop Manual

Air Top 2000 STC
ATTENTION
In vehicles used to transport persons, the air outlet opening
is to be arranged such that it is at least 20 cm away from any
parts of the body.
When switched on, the heater automatically checks the
internal rise in temperature. If the rise in temperature is above
the specified limit, the start-up procedure is cancelled and an
error message (see "Troubleshooting" on page501)
displayed. The resistance to flow in the connected heating air
system must be reduced to ensure stable heater operation.
If a filter is used for the heating air, it must have the following
properties:
• The flow of air must not carry any flammable and/or
harmful fibres or particles into the heater and the vehicle
interior.
• The filter material must be able to withstand
temperatures of at least 60 °C
• The filter material must be resistant to all substances that
may be drawn in with the heating air. (e.g. moisture, salt,
fuel vapours, etc.)
• The resistance offered by the filter must be taken into
account when layouting the heating air circuit.

8.6.2 Fuel supply

CAUTION
Risk of fire by fuel escaping from leaking plastic fuel
tank.
Skin burns
– Do not drill into a plastic fuel tank.
– When retrofitting the fuel take-off system on a plastic
tank: Install the Webasto tank extracting device only on
the vehicle's fuel delivery unit.
Refer to the Air Top 2000 STC installation instructions for
requirements relating the fuel system.
8.6.2.1 Fuel take-off, general
The fuel is taken from the vehicle's fuel tank or from a
separate fuel tank.
Make sure that the installation location meets the following
requirements:
– Fuel can be taken directly from the fuel tank.
– Fuel must be taken from the vehicle's fuel tank or a
separate fuel tank.
– Only use the genuine Webasto tank extracting device.
– Make sure that the swirl pot is not completely emptied
during operation.
See accessories catalogue for suitable tank extracting device.
NOTE
8.6.2.2 Permissible fuel pressure fuel line lengths.
D
2
l
2
Fig. 801 Fuel line lengths, inside diameter and height
differences (fuel tank, heater) to fuel pump
To Fig. 801:
Parameter
Inside diameter of fuel line D , D [mm]
1 2
Length of intake pipe l [m]
1
Length of pressure pipe l [m]
2
Length of intake pipe l + length of pressure pipe l
1
[m]
Distance from tank filling level - fuel pump
(Tank above fuel pump [m]) H [m]
1
Distance from tank filling level - fuel pump
(Tank below fuel pump [m]) S [m]
1
Height difference between heater and fuel pump
(Heater above fuel pump) H [m]
2
Height difference between heater and fuel pump
(Heater below fuel pump) S [m]
2
* Petrol heater: only pressure pipe with rising gradient
permitted
Maximum permissible fuel pressure
Distance between fuel level and
fuel pump (tank above fuel
pump [m]) H
1
H
= 0
1
H
0 < ≤ 1
1
1 < H ≤ 2
1
Distance between fuel level and
fuel pump (tank below fuel
pump [m]) S
1
S
= 0
1
S
-0.5 < < 0
1
-1.0 < S ≤ -0.5
1
-1.3 < S ≤ -1.0
1
8 Servicing
H
2
l
2
D
1
l
1
D
2
l
1
Value
Petrol
max. 2
max. 5
max. 10
max. 12
2
max. 2
max. 1 max. 1.3
max. 3
max. 0*
NOTE
Maximum permissible fuel pressure at take-off
point, p [bar]
1
Petrol Diesel
p p
-0.1 ≤ ≤ +0.3 -0.1 ≤
1
p p
-0.1 ≤ ≤ +0.2 -0.1 ≤
1
-0.1 ≤ p ≤ +0.1 -0.1 ≤ p
1
Maximum permissible fuel pressure at take-off
point, p [bar]
1
Petrol Diesel
p
-0.1 ≤ ≤ +0.3
1
p
-0.06 ≤ ≤ +0.3
1
-0.1 ≤ p
-0.02 ≤ p ≤ +0.3
1
-
H
1
S
1
Diesel
max. 1
≤ +0.5
1
≤ +0.4
1
≤ +0.3
1
≤ +0.5
1
802