baltur TBG 50LX PN ME Mode D'emploi page 34

D E S C R I P T I O N
O P E R AT I O N S AT T W O
STAGE PROGRESSIVE
These burners are of the blown air type
which have a mixture of gas/air at the
combustion head. They are suitable for
use with combustion chambers which
are either raising high pressure or re-
ducing pressure,together with excel-
lent fl ame stability, these burners are
safe and highly effi cient.
The burner has an electronic cam mod.
MPA 22. The microprocessor-controlled
MPA22 provides intermittent operation,
controlling and monitoring the electro-
nically modulated gas jet burners with
a servomotor to adjust the air fl ow rate
and a proportional type pneumatic val-
ve to adjust the gas fl ow rate. As an
automatic burner valve seal control is
activated; for a better understanding of
the MPA 22 read the instructions in the
attached manual, code 0006080905.
Operation of is of the progressive
two-stage type, so called because the
switch from primary fl ame to secondary
fl ame (from minimum to the set maxi-
mum) occurs gradually as regards the
delivery of both combustion air and
fuel; this gives considerable advanta-
ges in terms of the pressure stability in
the gas feed line. Delivery rate ranges,
approximately, 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 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.The gas supply is regulated
by the pneumatic valve.Three secon-
ds 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 de-
tected by the relative control device (an
ionisation sensor positioned inside the
fl ame).The programming relay passes
the stop position and powers the air
delivery regulation servomotor, which
moves to a position corresponding to
the minimum setting (P1). Triggering
of the pneumatic valve results in the
fl ow of gas being reduced to the mini-
mum thermal capacity.If the 2nd stage
boiler thermostat (or pressure switch)
adjusted by a temperature or pressu-
O F
re greater than that in the boiler) allow
the air adjustment servo motor starts to
turn causing gradual increase in com-
bustion air supply and, consequently
also of gas, up to the maximum supply
for which the burner has been set (point
P9). The increase in the fan air pressu-
re is detected by the proportional gas
valve sensor which gradually adjusts
gas supply to the change in air pressu-
re.The burner remains in the maximum
delivery position until the temperature
or pressure reaches the limit set for the
intervention of the boiler thermostat (or
pressure switch) of the 2nd stage and
makes the servomotor regulating air
delivery rotate in the opposite sense of
direction. Thus gas delivery and the re-
lative combustion air are gradually re-
duced 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 brought to
a standstill. When the temperature 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 boiler
thermostat (or pressure switch) of the
2nd stage fi tted to the boiler detects the
variations requested and automatically
34 / 69
0006081046 - ed 2006/09
Legend:
1 - Main switch on/off
2 - Thermostats line switch
3 - Display MPA 22
4 - Interference confi rm or elimination button
5 – Fuse
proceeds with adapting the fuel and
combustion air delivery by inserting
the servomotor which regulates delive-
ry. This will rotate in such a way as to
obtain an increase or a decrease. With
this manoeuvre, the modulation regu-
lating 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
error message 25H) on display (3)).
To "unblock" the equipment press the
interference
about half a second (4).
elimination button for