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6.7.1
Air / gas adjustment and output modulation
The burner system for air/fuel adjustment and power modulation
performs - in one single control device - a series of integrated
functions to obtain optimal energy/operating efficiency from the
burner, both for single operation and when combined with other
units (e.g. double furnace boiler or several generators working in
parallel).
The basic system functions control:
1
The dosage of the air and fuel through positioning using
direct servo-commands of the relevant valves eliminating
the possible play in the calibration systems with mechanical
cam levers, used on traditional modulating burners;
2
The modulation of the burner output in accordance with the
load required by the system, with maintenance of the pres-
sure or temperature of the boiler at the operating values set
3
the fine, continuous adjustment of the air flow rate according
to the gas analysis made at the flue (O2); this function is
dependent on the presence of the O2 kit, containing the PLL
module and the QGO2 sensor;
4
the measurement of the combustion yield (this function
requires the O2 kit);
5
the sequence (cascade adjustment) of several boilers, suita-
bly connected.
Further interfaces and communication functions with computers,
for remote control or integration in central supervision systems
are available on the basis of the configuration of the system.
6.8
Pressure switch adjustment
6.8.1
Air pressure switch
Adjust the air pressure switch after performing all other burner
adjustments with the air pressure switch set to the start of the
scale (Fig. 24). With the burner operating at MAX. output, in-
crease adjustment pressure by slowly turning the relative knob
clockwise until the burner locks out. Then turn the knob anti-
clockwise by about 20% of the set point and repeat burner start-
ing to ensure it is correct. If the burner locks out again, turn the
knob anti-clockwise a little bit more.
In conformity with current standards, the air pres-
sure switch must prevent the CO in the flue gases
exceeding 1% (10,000 ppm).
WARNING
6.8.2
Maximum gas pressure switch
Adjust the maximum gas pressure switch after having performed
all the other burner adjustments with the maximum gas pressure
switch set at the end of the scale (Fig. 25). With the burner oper-
ating at MAX output, reduce the adjustment pressure by slowly
turning the adjustment knob anticlockwise until the burner locks
out. Turn the knob clockwise by 0.2 kPa (2 mbar) and repeat the
start-up of the burner.
If the burner locks out again, turn the knob again clockwise by
0.1 kPa (1 mbar).
Start-up, calibration and operation of the burner
The first start up and every further internal setting
operation of the adjustment system or the expan-
sion of the base functions require access by
WARNING
means of password and are to be carried out by
service personnel who are especially trained for
the internal programming of the instrument and
the specific application created with this burner.
The first start-up and curve synchronisation manual is supplied
with the burner.
At request, the complete manual for the control and setting of all
parameters is available.
6.7.2
Pressure switch adjustment
Since the reference pressure values still cannot be established,
before starting the calibration, the following operations must be
carried out (with the burner off):
•
open the manual valves up-line of the gas train;
•
adjust the minimum gas pressure switch (Fig. 26) on the gas
train to the start of the scale;
•
adjust the maximum gas pressure switch (Fig. 25), on the
butterfly valve, to the end of the scale;
•
adjust the maximum air pressure switch (Fig. 24), on the
burner's air box, to the start of the scale.
23
GB
D3854
D3856
Fig. 24
Fig. 25
20124993
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