Nilfisk-ALTO NEPTUNE 5-46 PE, Service Manual

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36
NEPTUNE PE-DE_en_Ver.1.0_October 2010
Function
Heat exchanger NEPTUNE PE
The heat exchanger is the func-
tional link between the heating sub-
system and the water subsystem.
In "Hot water" mode the burner fan
(1) draws in air and conducts it lat-
erally into the heat exchanger
where it is routed upwards between
the two jackets to the baffle plate
(2). This preheats the air before it
mixes with the fuel spray from the
fuel nozzle (3).
Cold water is fed to the inner circuit
in which the temperature is highest.
This reduces in as much as possi-
ble any condensation on the sur-
face of the heating coil (4).
At the same time fuel is drawn in
from the fuel tank by the fuel pump
(5) through the filter (6). The fuel is
conducted by the solenoid valve (7)
to the nozzle stock (8) with the fuel
nozzle (3). If no combustion is
needed, the fuel goes back to the
tank on the return line (9).
The ignition transformer (10) acti-
vated in "Hot water" mode gener-
ates ignition sparks across the elec-
trodes (11) to ignite the fuel spray.
This process is monitored by the
flame sensor (12).
In normal operation the hot exhaust
flows downwards and upwards be-
tween the piping of the heating coil
(4) thus warming the water in the
system.
The exhaust exits through the flue
(13).
Heat exchanger (schematic)
Fig. D.19:
1) Burner fan
2) Baffle plate
3) Fuel nozzle
4) Heating coil
5) Fuel pump
6) Fuel filter
7) Solenoid valve
8) Nozzle stock
9) Fuel return line
10) Ignition transformer
11) Ignition electrodes
12) Flame probe
13) Flue
14) Flame sheath
15) Flame funnel
16) Insulation
17) Water inlet
18) Water outlet
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