46
9)
After this regulation, stop the burner and start it again several times for being sure that starting is correct.
10)
With the burner turned off from the main switch, connect the second flame thermostat terminals directly (bridge).
Set the combustion air regulator in the position you presumably need for adding the second flame (see
BT 8653/1). Turn on also the gas flow regulator built in the second valve in order to supply the amount of gas you
presumably need for the main flame.
11)
Now turn off the main switch for starting the burner.
When the burner is running, with the second flame, you should check gas delivery (read the meter) as described
above.
On the basis of checks carried out, change if necessary gas delivery in order to adjust it to the desired value
according to specific case (boiler power).
Be sure that combustion is being carried out correctly by checking the relative instruments (CO
2
= 8 to 10% for
methane - max. CO = 0,1%).
In order to optimize combustion and for good stability of the flame (no pulsation’s) you could need to operate on
the combustion head adjusting device.
Normally, you need to decrease the air flow between disk and head when the burner is running with reduced fuel
delivery. This air way must be proportionally larger when the burner is working with an increased fuel delivery.
If the combustion head is pushed forward (narrower way between disk and head) you must avoid complete
closure.
While adjusting the combustion head, you must center the head to the disk perfectly.
Remember that imperfect centering of the combustion head to the disk may result in bad combustion and
overheating of the head with its subsequent rapid deterioration.
Check centering by looking through the inspection hole placed on the back part of the burner, then, tighten firmly
the two screws fastening the combustion head in its position.
