Combustion Air Adjustment; Air / Gas Adjustment And Output Modulation; Pressure Switch Adjustment - Riello DB 2 LSE FGR Installation, Use And Maintenance Instructions

5.8

Combustion air adjustment

Fuel/combustion air synchronisation is done with the relevant
servomotors (air and gas) by logging a calibration curve by
means of the electronic cam.
It is advisable, to reduce the loss and for a wide calibration field,
to adjust the servomotors to the maximum of the output used, the
nearest possible to the maximum opening (90°).
On the gas butterfly valve, fuel step according to the burner out-
put required, with servomotor completely open, is carried out by
the pressure stabiliser placed on the gas train.
The values shown in Tab. L can be used as a reference for cali-
brating the combustion well.
5.8.1

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.
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
means of password and are to be carried out by
WARNING
service personnel who are especially trained for
the internal programming of the instrument and
the specific application created with this burner.
NOTES
The first start-up and curve synchronisation manual is sup-
plied with the burner. At request, the complete manual for
the control and setting of all parameters is available.
20169116
Start-up, calibration and operation of the burner
EN 676
Theoretical max
GAS CO
2
0 % O
2
G 20 11.7
G 25 11.5
G 30 14.0
G 31 13.7
EN 267
Theoretical max CO
0 % O
2
15.2
5.8.2

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. 33 on page 29)
on the gas train to the start of the scale;
• adjust the maximum gas pressure switch (Fig. 32 on
page 29), on the butterfly valve, to the end of the scale;
• adjust the maximum air pressure switch (Fig. 31 on page 29),
on the burner's air box, to the start of the scale.
28 GB
Air excess
Max. output.
 1.2
CO % Calibration
2
 = 1.2  = 1.3
9.7 9.0
9.5 8.8
11.6 10.7
11.4 10.5
Air excess
Max. output.
 1.2
CO % Calibration
2
2
 = 1.2  = 1.3
12.6 11.5
Min. output
 1.3
CO
mg/kWh
 100
 100
 100
 100
Min. output
 1.3
CO
mg/kWh
 100
Tab. L