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0006080873_00709
DUAL FUEL BURNER’S FIRING INDICATIONS
We suggest to start the burner with the liquid fuel, as in this case the delivery is bound to the nozzle size whilst
the gas delivery can be easily changed by acting on the relative capacity adjuster.
If the burner is in the automatic version, the selector for the fuel change connects a cyclic relay which inserts,
thanks to an auxiliary relay, components for the use of both fuels (valves, pressure switches, pump etc.).
After having changed the position of the selector from gas to light oil and viceversa, it occurs to leave it stopped
for at least 10 seconds which is the time the cyclic relay needs to carry out its program.
Note
: If the selector is moved from a position to another before the period of 10 seconds, the cyclic relay stops
in the
middle of its program not allowing to use the burner both with gas and with light oil.
PREPARATIONS FOR IGNITION WITH LIGHT OIL
Control that the nozzle applied is suitable for the boiler potentiality.
The table shows delivery rates in kg/h of light oil with respect to the nozzle size and the pump pressure (normally 20
bar for the 2nd flame). It should be remembered that 1 kg of light oil is equivalent to approximately 10.200 kcal.
When choosing the nozzle (45° spary angle) it should be kept in mind that fuel delivery at the 1st flame must not
be considerably lower than the minimum output of the burner (see the burner rating plate).
Check that the combustion head penetrates the combustion chamber to the extent specified by the boi
-
ler manufacturer.
Make sure that the ruturn pipe in the tank has no obstructions, e.g. gate valves closed, plugs
etc.
Any eventual obstruction would cause a brekage in the sealing surface situated on the pump shaft or of the flexi
-
ble pipe. Eliminate the connection or “bridge” to the 2nd flame thermostat. Open, by loosening, the special fitting
which the pump has been provided with to purge air. When fuel is seen coming out of the air purge device, open
the main switch to stop the motor. The burner is now ready to be started up with light oil.
LIGHT OIL IGNITION AND ADJUSTMENT
1) Check that the pump and fan motors rotate in the right direction.
2) Make sure that the discarge of combustion products can take place freely (chimney lock-gates should be open)
and that there is water in the boiler.
3) Open, as much as considered necessary, the combustion air regulator (see drawing air regulation servomotor
cod. 0002932130) and open by about half the air passage between thehead and the disk by operating the
regulating screw of the flame disk.
4) Disconnect the
nd
flame thermostat to avoid the ignition of this same flame, close the main switch in order
to connect the burner and wait for it to start up. With the burner operating at 1
st
flame correct, if necessary,
the combustion air delivery. The pump pressure for the “1
st
flame” should be 10 bar. After regulation, turn off
the burner and then turn it on again in order to verify that ignition occurs correctly. It should be remembered
that, in order to ensure a soft ignition, it is necessary to regulate in such a way that the quantity of air is the
minimum indispensable. If ignition takes place softly, disconnect the burner from the main switch and make a
direct connection (bridge) between the 2
nd
flame thermostat terminals.
5) Regulate the combustion air in the position considered necessary for insertion of the 2
nd
flame
(see air regulation servomotor cod. 00093130).
6) Now, connect again the burner which will start operating with the 1st and 2nd flames. Operate the air regulation
cam of the
nd
flame in order to adapt its delivery to the specific conditions. The pump pressure for the “2
nd
flame” should be 20 bar.
7) The burner is fitted with a device which optimizes the combustion by reducing or increasing the air passage
between the disk and the head. Maximum smoke intensity permissable is n° 2 of the Bacharach scale, with
a Carbon Dioxide (CO
) value of between 10 and 13%. It is normally necessary to reduce the air passage
between the disk and the head when operating with a reduced fuel delivery. This passage must be proportio
-
nately opened more when the burner is working with a higher fuel delivery. When modifying this position, it is
normally necessary to correct the position of the air regulation shutters of the 1
st
and
nd
flames, and
subse-
quently
, verify that ignition occurs correctly.
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