Burner Start-Up; Burner Ignition; Burner Adjustment; Ignition Output - Riello RS 70/M Installation, Use And Maintenance Instructions

5.4

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 in
Fig. 29 to position "MAN".
As soon as burner starts, check the fan rotation direction
through the flame inspection window.
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. If they
DANGER indicate the presence of voltage, stop the burner
immediately and check the electric connections.
5.5

Burner ignition

If the motor starts up, but 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 sleeve is indicated by the U-type
pressure gauge (Fig. 27 on page 24).
Once ignition has taken place, proceed with burner global
calibration operations.
5.5.1

Burner adjustment

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

Ignition output

2

Maximum output

3 Minimum output
4 Intermediate outputs between the two
5 Air pressure switch
6 Maximum gas pressure switch
7 Minimum gas pressure switch
5.5.2 Ignition output
According to standard EN 676.
Burners with MAX output up to 120 kW
Ignition can occur at the maximum operation output level.
Example:
• max. operation output: 120 kW
• 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 be defined according to the
control box safety time "ts":
for "ts" = 3s, ignition output must be equal to or lower than 1/3
of max. operation output.
Example
MAX operation output of 600 kW.
Ignition output must be equal to or lower than:
• 300 kW with ts = 2 s.
• 200 kW with ts = 3 s.
Start-up, calibration and operation of the burner
120 kW
In order to measure the ignition output:
 disconnect the plug-socket 1)(Fig. 5 on page 11) on the
ionisation probe cable (the burner will ignite 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:
3
Sm
Example for G 20 gas (9.45 kWh/Sm
Max. operation output: 600 kW corresponding to 63.5 Sm
After 10 ignitions with a lockout, the delivery indicated on the
meter must be equal to or lower than: 63.5 : 360 = 0.176 Sm
Air adjustment
The air is adjusted by changing the angle of cam III)(Fig. 28 on
page 24) and by using the selector 2)(Fig. 29 on page 25).
To adjust the cam of the servomotor, see Fig. 31.
5.5.3 Maximum output
The MAX output must be set within the firing rate indicated in
Fig. 2 on page 9.
In the above instructions we left the burner running at the MIN
output.
Now press the "increase output" button 2)(Fig. 29 on page 25),
and keep it pressed until the servomotor has opened the air
damper and the gas butterfly valve.
Adjustment of gas delivery
Measure the gas delivery on the meter.
A rough indication can be obtained from Tab. H on page 21, just
read the gas pressure on the "U" pressure gauge (see Fig. 27 on
page 24) and follow the indications.
 If delivery needs to be reduced, diminish outlet gas
pressure; if it is already very low, slightly close the VR
adjustment valve.
 If delivery needs to be increased, increase the adjuster
outlet gas pressure.
25 GB
1 2
D791
/h (max. burner delivery)
360
3
):
Fig. 29
3
/h.
3
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