Electrical Connections; Description Of The Operation; Combustion Control - baltur BGN LX series Betriebsanleitung

ELECTRICAL CONNECTIONS

The three-phase or single-phase power supply line of the minimum suitable size for the power absorbed by the burner
must be provided with fuse switch. In addition, according to the Standards, a switch on the burner supply line is
required, arranged outside the boiler room in an easily reachable position.
All electrical lines must be protected with a flexible sheath, be firmly fixed and pass far from high-temperature ele-
ments. See the diagrams for the electrical connections (line and thermostats).

DESCRIPTION OF THE OPERATION

In the burner, by closing the main circuit breaker if the thermostats are off, the control box is supplied. The fan motor is
thus enabled, and its operation determines the pre-ventilation of the combustion chamber. At the same time, the
combustion air damper control motor opens the air damper in the position corresponding to the maximum set.
The combustion chamber pre-ventilation step thus occurs with air damper in the high flame position. At the end of the
pre-ventilation step, the combustion air damper is restored to the ignition flame position. If the ventilation air pressure
control switch detects a sufficient pressure, the ignition transformer is started and the gas valves (main and safety) are
opened. The burner starts.
The quantity of gas (m 3 /h) supplied with the ignition flame can be regulated by operating on the air damper
control servomotor (see N° 0002933220 from BGN 40LX to BGN 390LX) (see N° 0002933490 for BGN 540LX).
Note: The ignition flame has a higher gas flow rate than the minimum modulation flow rate.
The flame is thus present and, detected by its control device, it allows continuing and ending the ignition step by
disabling the ignition transformer. The quantity of gas supplied with the high flame must be regulated by operating on
the air damper control servomotor (see dr. n° 0002933220 - 0002933490).
In case of absence of ignition flame, the control box stops in "safety lock". In case of "safety lock" the valves are closed
immediately. To unlock the control box from the safety position, press the luminous button on the control box.
Note: For the gas valve regulation, see the specific instructions in the following pages. The air damper is actuated by
a special electrical motor (see specific instructions in the following pages), note that as the burner is shut down by the
thermostat enable, the air damper is restored to the total closure position by the control motor.
DESCRIPTION OF THE MODULATION OPERATION
When the burner is on at the minimum flow rate, if the modulation sensor allows it (adjusted to a higher pressure or
temperature value than that in the boiler), the air regulation servomotor start running, thus determining a gradual
increase of the combustion air supply, and consequently, of gas, until the maximum supply at which the burner is
regulated is reached. The air pressure increase in the ventilator is detected by the gas valve sensor, model MB-VEF..
or DMV-VEF.., which gradually adjusts the gas supply to the also gradual air pressure variation.
The burner remains in the maximum supply position until the temperature or pressure reaches a sufficient valve to
determine the intervention of the modulation sensor, which makes the air regulation servomotor run in the reverse
direction with respect to the previous one. The backward rotation and the air and gas supply reduction occur at short
time intervals. With this operation, the modulation system attempts to balance the quantity of heat supplied to the boiler
with that yielded by the same during use. The modulation probe applied to the boiler detects the request variations and
automatically provides to adjusting the fuel and the combustion air supply by enabling the air regulation servomotor
with increasing or decreasing rotation. If the limit value (temperature or pressure) is reached also with minimum supply
to which the total shut down device is set (thermostat or pressure switch), the burner is shut down by the intervention
of the same. As the temperature or pressure fall below the shut down device enable value, the burner is started again
according to the previously described program. If the flame does not appear, the control box "locks" (total burner shut
down and lighting of the relevant warning light). To "unlock" the control box, press the special push button.

COMBUSTION CONTROL

For a correct air/gas ratio, the methane carbon dioxide (CO ) value must be at least 8% at the minimum burner supply,
2
up to an optimum value of 10% for maximum supply. It is advisable not to exceed a 10% value so as to prevent
operation with too limited air excess, which could cause (atmospheric pressure variation, presence of dust in the air
ducts) a sensible CO (carbon oxide) quantity. To prevent dangerous situations, the carbon oxide (CO) percent-
age in the flue gas must always measured with the special instrument to make sure that it does not exceed the
maximum admissible value of 0.1%.
EN
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