baltur BGN 200 DSPGN-ME Mode D'emploi page 37

DESCRIPTION OF
OPERATIONS AT
MODULATION FLAME
The approximate delivery variation
range is, indicatively, from 1 to
1/3. Ignition is preceded by pre-
ventilation of the combustion
chamber as per standards, with
the air open: this lasts about 36
seconds. If, at the end of the
ventilation stage, the ventilation
air pressure control switch detects
that pressure is suffi cient, the
ignition transformer comes on and,
after 3 seconds, the safety and
main valves open in sequence.
The gas reaches the combustion
head, is mixed with the air being
delivered by the fan, and is ignited.
Delivery is regulated by the gas
throttle valve. Three seconds
after the (main and safety)
valves are opened the ignition
transformer is switched off. The
burner is now on at the ignition
point (P0). The fl ame is detected
by the relative control device (an
ionisation sensor positioned inside
the fl ame). The programming
relay goes beyond the shutdown
position and powers the air/gas
delivery regulation servomotors,
which go to minimum (P1). If the
modulation sensor – adjusted by
a temperature or pressure lower
than that in the boiler) – allows,
the air/gas delivery servomotors
start running and cause a gradual
increase is the delivery of gas and
combustion air until the maximum
fl ow rates to which the burner has
been set have been reached (point
P9).
N.B. Electronic cam MPA 22
controls the burner by adjusting
the combustion air and gas
servomotors according to a pre-
set operating curve.
The burner remains at the maximum
delivery position until the temperatu-
re or pressure reaches the limit set
for the intervention of the modulation
probe and makes the servomotors
regulating gas/air delivery rotate
in the opposite sense of direction.
Thus gas delivery and the relative
combustion air are gradually redu-
ced until they reach minimum level.
Even with delivery at a minimum, if
the limit (temperature or pressure)
at which the shut down device (ther-
mostat 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 fi tted to the boiler
detects the variations requested
and automatically proceeds with
adapting the fuel and combustion
air delivery by inserting the servo-
motors 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 de-
livery regulating system try's to equi-
librate the quantity of heat supplied
to the boiler with that which the boiler
gives to be utilised. If the fl ame does
not appear within THREE seconds
of the opening of the gas valves,
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.
STARTING UP AND
REGULATION WITH
METHANE
1) If not already done at the mo-
ment of connecting the burner to
the gas pipeline, it is indispen-
sable to carry out a purge of the
air contained in the pipeline.
As a precaution, special care
should be taken and doors and
windows should be opened.
Open the pipe union on the pi-
peline situated near the burner
and then open a little the gas
cut-off cock (or cocks). When
the characteristic odour of gas
can be smelled, close the cut-off
cock. Wait until the gas present
in room has dispersed, and then
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reconnect the burner to the gas
pipeline. Subsequently, re-open
the gas cut-off cock.
2) Check that there is water in the
boiler and that the system's gate boiler and that the system's gate
valves are open. valves are open
3) Check, with absolute certainty Check, with absolute certainty
that the discharge of combustion that the discharge of combustion
products can take place freely products can take place freely
(boiler and (boiler and chimney lock-gates chimney lock-gates
should be open). should be open)
4) Make sure that the voltage of the
electric line to which the burner
is to be connected,corresponds
to that required by the burner
and that the electrical connec-
tions (motor and principle line)
have been prepared to mach
the voltage rating available.
Also check that all the electrical
connections carried out on the
spot are in accordance with our
electric wiring diagram.
5) Make sure that the combustion
head is long enough to enter the head is long enough to enter the
furnace to the extent specifi ed by furnace to the extent specifi ed by
the boiler manufacturer. Check
that the device which regulates
the air on the combustion head
is in the position considered
necessary for the fuel delivery
required (air passage between
the disk and the head should be
considerably reduced when the
fuel delivery is reduced; on the
other hand, when the fuel delive-
ry is fairly high, the air passage
between the disk and the head
should be relatively open). See
Chapter "Air Regulation on the
Combustion Head".
6) Apply a manometer with an
adequate scale (if the entity of
pressure forecast allows it is
preferable to use a column of
water instrument, do not use a
pointer instrument for moderate
pressure) to the pressure plug
on the gas pressure switch.
7) With the switch "1" on the control
panel in the "o" position and the
main switch inserted check, by
manually closing the relay, that
the motor rotates in the right di-
rection. If it does not, exchange