baltur BGN 100 DSPGN, Instructions Manual

Page: 13 / 48

13
DESCRIPTION OF OPERATIONS FOR BGN...M (See 0002910611 and 0002910640)
The field of variation in flow obtainable is from 1 to 1/3.
The burner is fitted with an end-of-the-run switch (a micro-switch) which stops the burner starting up if the flow regulator
is not in the minimum position. Before ignition, a pre-ventilation of the combustion chamber occurs (according to
Regulations) with air open. This lasts for about 120 seconds).
At the end of the ventilation phase, if the air ventilation pressure switch has measured sufficient pressure, the ignition
transformer will be connected and, after four seconds, the ignition flame (pilot) valves and the safety valve will open.
Gas reaches the combustion head, mixes with air supplied by the fan, and is ignited.
Delivery is regulated by the flow regulator incorporated in the ignition flame (pilot) valve.
The ignition transformer is disconnected two second after the ignition flame and safety valve are inserted. The burner is
now operating with the ignition flame (pilot) only. Flame presence is detected by a relative control device (ionisation
probe immersed in the flame, or UV Cell). The relay programmer passes the “shut down” position and gives voltage to
the servomotor which regulates the delivery (gas/air); the burner is now operating at minimum output.
If the modulation probe allows it (regulated at a temperature or pressure value superior to that existing in the boiler), the
servomotor which regulates the gas/air delivery starts turning and determines a gradual increase in the gas delivery and
in the relative combustion air until it reaches the maximum delivery value at which the burner has been regulated.
N.B. The “V” cam of the servomotor regulating air/gas delivery (see BT 8562/1) or the V cam of the air/gas delivery
regulating servomotor (see drawing n° 0002931170) inserts almost immediately the principle gas valve, which in
turn opens completely. Gas delivery is not determined by the principle valve but by the position of the gas delivery
regulation valve (see BT 8816, BT 8813/1 and drawing n° 0002910060).
The burner remains at the maximum delivery position until the temperature or pressure reaches the limit set for the
intervention of the modulation probe and makes the servomotor regulating gas/air delivery rotate in the opposite sense
of direction. Thus gas delivery and the relative combustion air are gradually reduced until they reach minimum level.
Even with delivery at a minimum, if the limit (temperature or pressure) at which the shut down device (thermostat or
pressure switch) has bee regulated is reached, the burner will be brought to a standstill.
When the temperature or pressure drops below the intervention limit set on the shut down device, the burner will start
up again, according to the programme previously described.
During normal operations, the boiler modulation probe fitted to the boiler detects the variations requested and automatically
proceeds with adapting the fuel and combustion air delivery by inserting the servomotor which regulates delivery (gas/
air). This will rotate in such a way as to obstain an increase or a decrease.
With this manoeuvre, the gas/air delivery regulating system try’s to equilibrate the quantity of heat supplied to the boiler
with that which the boiler gives to be utilised.
If the flame does not appear within two seconds of the opening of the first flame valve (pilot), the control box goes to
“shut down” (the burner stops completely and the relative indicator light is turned on).
To unblock the control box, press the appropriate push-button.