38
ELECTRICAL CONNECTIONS
The three-phase or single-phase electric supply line of the minimum section, in proportion to the power absorbed by
the burner, must be equipped with a fused switch.
Furthermore, regulations require a switch on the burner’s feed line which should be located outside the boiler room in
an easily accessible position.
All electric lines must be protected by flexible sheaths, be firmly secured and be laid a long way from high temperature
parts.
For the electrical connections (line and thermostat) see the relevant diagram.
DESCRIPTION OF OPERATIONS FOR BGN...M (See 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 41 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 3 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 3 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 gas/air delivery (see BT 8919) 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 8918).
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 3 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.
Summary of Contents for BGN 17 DSPGN
Page 20: ...20 SCHEMA DI PRINCIPIO REGOLAZIONE ARIA PER BRUCIATORI A GAS N BT 8769 1 IT...
Page 29: ...29 APPARECCHIATURA DI COMANDO E CONTROLLO PER BRUCIATORI A GAS LMG 2 IT...
Page 30: ...30 APPARECCHIATURA DI COMANDO E CONTROLLO PER BRUCIATORI A GAS LMG 2 IT...
Page 31: ...31 APPARECCHIATURA DI COMANDO E CONTROLLO PER BRUCIATORI A GAS LMG 2 IT...
Page 32: ...32 APPARECCHIATURA DI COMANDO E CONTROLLO PER BRUCIATORI A GAS LMG 2 IT...
Page 45: ...45 N BT 8769 1 AIR REGULATION PRINCIPLE DIAGRAM FOR GAS BURNERS EN...
Page 52: ...52 EN...
Page 53: ...53 EN GAS BURNER CONTROLS LMG 2...
Page 54: ...54 EN GAS BURNER CONTROLS LMG 2...
Page 55: ...55 EN GAS BURNER CONTROLS LMG 2...
Page 56: ...56 EN GAS BURNER CONTROLS LMG 2...
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