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DESCRIPTION OF OPERATION
WITH LIQUID FUEL
It is not advisable to oversize the burner with respect to the boiler
for heating and hot water production purposes as the burner may
work for long periods with a single flame, making the boiler work at
lower outputs than the required ones; as a result, the combustion
products (fumes) emerge at too low a temperature (at about 180° C
in the case of fuel oil and 130° C with diesel oil), causing soot to build
up at the chimney outlet. Furthermore, when the boiler operates at
a capacity lower than what is indicated in the technical data, it is
very probable that acid condensate and soot will form in the boiler,
causing its rapid clogging and corrosion. When the two-flame burner
is installed on a boiler for the production of hot water for heating
purposes, it must be connected so it can operate under normal
conditions with both flames, completely stopping, without operating
at the first stage, when the predefined temperature is reached. To
obtain this particular operation, do not install the second stage
thermostat and make a direct connection between the terminals
of the 4-pole plug (jumper). In this way, only the burner's capacity
will be used for ignition at a reduced flow rate for a soft start, which
is an essential condition for boilers with a pressurized combustion
chamber, but also very useful for normal boilers (vacuum combustion
chamber). The burner's command (on or off) is connected to the
normal operating or safety thermostats.
With main switch (1) in the "on" position, closing the switch (11) if
the thermostats are closed, the command and control equipment
starts its operation. In this way, the motor starts, puts the fan in
rotation and washes inside the combustion chamber, allowing the
circulation of fuel through the pump and expelling any gas bubbles
from the return circuit of the pump. This pre-wash stage ends with
the opening of the safety solenoid valves and the first stage (LED
5), which allows the fuel at a pressure of 12 bar to get to the first
stage nozzle and from this to enter the combustion chamber finely
atomised. As soon as the atomized fuel exits the nozzle, it is set on
fire by the spark present between the electrodes since the start of
the motor. During first stage ignition, the air gate is held in the preset
position on the special air adjustment servomotor cam. If the flame
appears regularly, after the safety time foreseen by the electronic
device, it starts the air regulation servomotor that moves to the 2
stage position. During the transition from the first to the second
stage, the equipment operates the solenoid valve (normally closed)
of the 2
stage. The opening of the 2
nd
fuel, at a pressure of 12 bar, to reach the 2
to operate at full capacity. From the time the flame appears in the
combustion chamber, the burner is controlled by the photoelectric
cell and thermostats.
The command equipment continues the program and disconnects
the ignition transformer. When the temperature or pressure in
the boiler reaches the value to which the thermostat or pressure
switch is calibrated, its intervention will cause the burner to stop.
Subsequently, if the temperature of pressure decreases below the
lower thermostat or pressure switch threshold value, the burner will
switch on again. If, for any reason, the flame is lost during burner
operation, after just one second the flame control device cuts off
the power supply from the corresponding relay to automatically
switch off the solenoid valves which intercept the nozzle flow. The
equipment will shutdown automatically. If the program is interrupted
(due to a power supply failure, manual action or the intervention of
nd
stage valve allows the diesel
nd
nozzle and the burner
nd
14 / 30
0006160034_201307
the thermostat, etc.) during the pre-wash stage, the programmer
returns to its starting position and will automatically repeat the whole
of the burner ignition sequence.
The selection of the nozzles in function of the desired total
flow rate (2 nozzles in operation) must be made accounting
for the flow rate values that correspond to the operating
pressure of 12 bar. It is obviously possible to vary the ratio
between the first and second stage within the wide limits by
replacing the nozzles.
10
3
11
1
Main switch on / off
2
programming keys
3
Display
4
Confirm or RESET key
5
Fuse
9
Fuel fill button
10
Fuel switch
11
Thermostatic line switch
2
5
1
4
9
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