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0006081081_2006/10
HYDRAULIC DIAGRAM
N° 0002901440
REV.: 11-07-2006
1 - 1
st
stage nozzle
2 - 2
nd
stage nozzle
3 - atomizing group with adjustable closing device
4 - 1
st
stage nozzle closing device
(pressure selling 12 bar)
4/1 - 2
nd
stage nozzle closing device
(pressure selling 12 bar)
FRONT VIEW
5 - closing device adjusting screw
6 - 1
st
stage normally open valve
7 - 2
nd
stage normally closed valve
8 - fuel pump (pressure selling: 16 bar)
9 - return pipeline
10 - suction pipeline
11 - air control servomotor
If the fl ame appears normally, the
programmer overcomes the lock-
out position and switches on the
motor that moves the combustion
air damper until it is in its second
stage position.
During this manoeuvre an adjustable
cam, which is activated by the same
motor that moves the damper, closes
an electrical contact which takes the
current to the solenoid valve (7)
(closed during the rest phase).
The opening of the second stage
valve permits the fuel, at a pressure
of 16 bar, to reach the second
stage nozzle closing device n° 4/1.
The pressure acts on the second
stage nozzle closing device which,
up to a pressure of 12 bar, prevents
the fl ow of fuel to the second nozzle.
The pressure of 16 bar now acts on
both nozzles.
Note:
It is clear from the above that the
choice of nozzles, depending required
total flow (2 nozzles working),
must be made taking account of
the flow values corresponding
to a working pressure of 16 bar.
You must however bear in mind that
when the burner is working with
only the first stage switched on,
the supply of fuel corresponds to a
single nozzle at a pressure of 16 bar.
It is of course possible to change
the ration between fi rst and second
stage within wide limits by changing
the nozzles. Remember however
that for the good working of the
system, the supply of fuel in the fi rst
sage should not be less than the
minimum capacity (which is written
on the burner’s specifi cations plate).
A lower fl ow could make ignition
diffi cult and fi rst stage combustion
alone may not be good.
These burner models use three
nozzles; in the case of second stage
nozzles there are two and both are
at a pressure of 16 bar.
From when the fl ame appears in the
combustion chamber, the burner
is controlled by the photoelectric
cell and the thermostats. When the
temperature or pressure reaches
the value at which the thermostat
or pressure switch is calibrated for
working, the burner will stop when
it is triggered.
The control box starts working
again automatically when the
temperature or pressure is lowered
by the necessary amount. If, for
any reason, during the working, the
fl ame goes out, the photoelectric cell
intervenes immediately (within one
second) to stop the electrical supply
to the relay, causing it to open with
the result that wash solenoid valve
n°6, on opening, rapidly discharges
the existing pressure and the light
atomised oil spray is intercepted
by the automatic closing of the
atomisation unit nozzle as soon
as the pressure goes below set
pressure. The burner has a display
diagram switch (3) to go from the 1
st
to the 2
nd
stage.
