Burner Start-Up; Adjusting The Burner; Ignition Output; Ignition Output (Minimum) - Riello RS 25/M BLU Installation, Use And Maintenance Instructions

6.4

Burner start-up

Feed electricity to the burner via the disconnecting switch on the
boiler panel.
Close the thermostats/pressure switches and turn the switch of
Fig. 28 to position "1".
Check that the lamps or testers connected to the
solenoid valves, or the pilot lights on the solenoid
valves, indicate that no voltage is present.
DANGER
If they indicate the presence of voltage, stop the
burner immediately and check the electric
connections.
6.5

Adjusting the burner

The optimum adjustment of the burner requires an analysis of
flue gases at the boiler outlet.
Adjust in sequence:
1

Ignition output (minimum)

2 MAX output
3 Intermediate outputs between the two
4 Air pressure switch
5 Minimum gas pressure switch
6.5.1

Ignition output

According to EN 676.
Burners with MAX output up to 120 kW
Ignition can occur at the maximum operation output level.
Example:
– max. operation output:
– max. ignition output:
Burners with MAX output above 120 kW
Ignition must occur at a lower output than the max. operation
output.
If ignition output does not exceed 120 kW, no calculations are
required.
If ignition output exceeds 120 kW, the regulatory standard sets
that the value is to be defined according to the control box safety
time "ts":
for ts = 3 s ignition output must be equal to or less than 1/3 of the
maximum operation output.
Example:
MAX operation output of 450 kW.
The ignition output must be equal to or less than 150 kW with ts
= 3s
In order to measure the ignition output:
 disconnect the plug-socket 6)(Fig. 4 on page 13) on the
ionisation probe cable (the burner will fire and then go into
lockout after the safety time has elapsed);
 perform 10 consecutive ignitions with lockouts;
 read the quantity of burned gas on the meter:
this quantity must be equal to, or lower than, the quantity
given by the formula, for ts = 3 s:
Qa (max. burner delivery) x n x ts
Vg =
Vg volume supplied in ignitions carried out (Sm
3
Qa ignition delivery (Sm
n number of ignitions (10)
ts safety time (sec)
Start-up, calibration and operation of the burner
120 kW
120 kW
3600
3
)
/h)
Example for gas G20 (9.45 kWh/Sm
ignition output 150 kW corresponding to 15.87 Sm
After 10 ignitions with a lockout, the delivery indicated on the
meter must be equal to or lower than:
Vg =
6.5.2 Ignition output (minimum)
The MIN output must be set within the firing rate (Fig. 2 on
page 11).
Press and hold the "output reduction" button 2)(Fig. 31) until the
servomotor closes the air damper and the gas butterfly valve is at
15° (factory setting).
Adjustment of gas delivery
Measure the gas delivery on the meter.
– If it is necessary to reduce it, slightly decrease the angle of
cam III (Fig. 30) with small, regular movements, i.e. bring it
from an angle of 15° to 13° - 11°...
– If it is necessary to increase it, lightly press the "output
increase" button 2)(Fig. 31) (open the gas butterfly valve by
10-15°), and increase cam III angle (Fig. 30) with a series of
small movements, i.e. move from angle 15° to 17° - 19°...
Now press the "power reduction" button until the servomotor
returns to the minimum opening position, and measure the
gas delivery.
NOTE:
The servomotor follows the adjustment of cam III only when
the angle of the cam is reduced.
If it is necessary to increase the angle of the cam, you must
first increase the angle of the servomotor by means of the
"output increase" key, then increase the angle of cam III, and
finally bring the servomotor to the position of MIN output,
with the "output reduction" key.
If it is necessary to adjust cam III, remove the cover 1)(Fig. 29)
inserted with a trigger catch, as indicated in (Fig. 30), extract the
special key 2)(Fig. 30) from inside, and insert it in the notch of
cam III.
27 GB
D3833
3
):
15.87 x 10 x 3
= 0.132 Sm
3600
Fig. 28
3
/h.
3
20168415