baltur BGN 200 DSPGN-ME Mode D'emploi page 36

DESCRIPTION OF
OPERATIONS AT 2-STAGE
PROGRESSIVE
The burners are of the blown air
type which have an electronic mo-
dulation. They are suitable for use
with combustion chambers which
are either raising high pressure or
reducing pressure, according to the
relative work curves. Together with
excellent fl ame stability, these bur-
ners are safe and highly effi cient.
It is equipped with a steel fl ange
which slips on the burner head.
When fastening the burner to the
boiler it is necessary to correctly
position the fl ange so that the bur- position the fl ange so that the bur-
ner head enters the combustion
chamber to the extent specifi ed by chamber to the extent specifi ed by
the boiler manufacturer. The burner
has an electronic cam mod. MPA 22.
The microprocessor-controlled MPA
22 provides intermittent operation,
controls and monitors the electroni-
cally-modulated fan-equipped gas
burners and features two (air/gas)
adjuster motors. When working
as an automatic burner valve seal
control is activated; (for a better un-
derstanding of the MPA 22 read the
instructions in the attached manual,
code 0006080902).
Operation of is of the progressive
two-stage type, so called because
the switch from primary fl ame to
secondary flame (from minimum
to the set maximum) occurs gradu-
ally as regards the delivery of both
combustion air and fuel; this gives
considerable advantages in terms
of the pressure stability in the gas
feed line. Delivery rate ranges, ap-
proximately, from 1 to 1/3. Ignition
is preceded by pre-ventilation of the
combustion chamber as per stand-
ards, with the air open: this lasts
about 36 seconds. If, at the end of
the ventilation stage, the air pressure
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.
1 Main ON-OFF switch
2 Thermostat line switch
3 MPA 22.. diplay
correctly
D e l i v e r y i s r e g u l a t e d b y
t h e g a s
Three seconds after the (main and
safety) valves are opened the igni-
tion 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 in-
side the fl ame, or a UV photocell).
The programming relay goes beyond
the shutdown position and powers
the air/gas delivery regulation servo-
motors, which go to minimum (P1).
If the 2 stage boiler thermostat (or
nd
pressure switch) – adjusted by a
temperature or pressure greater than
that in the boiler) – allow, 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 con-
trols the burner by adjusting
the combustion air and gas
servomotors according to a
pre-set curve.
The burner remains in the maximum
delivery position until the temperatu-
re or pressure reaches the limit set
for the intervention of the boiler ther-
mostat (or pressure switch) of the 2
stage and makes the servomotors
regulating gas/air delivery rotate
in the opposite sense of direction.
0006081117_2006/09
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nd
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4 Confi rm or elimination
interference button
5 Fuse
Thus gas delivery and the relative
combustion air are gradually redu-
ced until they reach minimum value.
Even with delivery at a minimum, if
the limit (temperature or pressure at
the shut down device (thermostat or
pressure switch) has been regulated
is reached, the burner will be brou-
ght to a standstill. When the tem-
perature or pressure drops below
the intervention limit set on the shut
down device, the burner will star up
again, according to the programme
previously described.
During normal operations, the boi-
ler thermostat (or pressure switch)
of the 2 stage fi tted to the boi-
nd
ler detects the variations reque-
sted and automatically proceeds
with adapting the fuel and combu-
stion air delivery by inserting the
servomotors which regulates delive-
ry (gas/air). This will rotate in such
a way as to obtain 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 fl ame does not appear within
THREE seconds of the opening of
the gas valve, the control box goes
to "shut down" (the burner stops
completely and the relative indicator
light is turned on). To unblock the
control box,the eliminate interferen-
ce button must be pressed for about