Burner Ignition; Combustion Air Adjustment; Air / Gas Adjustment And Output Modulation; Pressure Switch Adjustment - Riello DR 25 SE C03 Installation, Use And Maintenance Instructions

5.5

Burner ignition

The burner should light after having performed the above steps.
If on completion of the starting cycle the flame does not appear
and the control box goes into lockout, reset it and wait for a new
ignition attempt.
If ignition is still not achieved, it may be that gas is not reaching
the combustion head within the safety time period of 3 seconds;
In this case increase gas ignition delivery.
The arrival of gas to the pipe coupling is indicated by the U pres-
sure gauge (Fig. 18) or using a digital pressure gauge on the
pressure test point below the pipe coupling.
If further burner lockouts occur, refer to the "Release procedure"
given in the supplied control box manual of the boiler control pan-
el.
Once the burner has fired, now proceed with global calibration
operations.
5.6

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 in the Tab. J can be useful as reference for a good
fuel calibration.
EN 676
Max. output.
Theoretical max
CO
GAS
2
0 % O
2
G 20 11.7
G 25 11.5
G 30 14.0
G 31 13.7
5.6.1

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 servocommands of the relevant valves eliminating the
possible play in the calibration systems with mechanical
cam leverages, 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
Start-up, calibration and operation of the burner
Air excess
Max. output.
  1.2   1.3
CO % Calibration
2
mg/kWh
 = 1.3
 = 1.2
9.7 9
9.5 8.8
11.6 10.7
11.4 10.5
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
CO
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.
The first start-up and curve synchronisation manual is supplied
 100
with the burner.
 100
At request, the complete manual for the control and setting of all
parameters is available.
 100
 100
5.6.2

Pressure switch adjustment

Tab. J
Being that the values of the reference pressures cannot be deter-
mined before starting the calibration, the following operations
must be performed (with burner off):
• open the manual valves upline of the gas train;
• adjust the minimum gas pressure switch (Fig. 25 a pag. 26)
on the gas train, to the start of the scale.
• adjust the maximum gas pressure switch (Fig. 24 a pag. 26)
on the butterfly valve to the end of the scale.
• adjust the air pressure switch (Fig. 23 a pag. 26), on the air
box of the burner, to the start of the scale.
25 GB
20159542