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Idiomas disponibles
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 redu-
cing pressure, according to the relative
work curves. Together with excellent
flame stability, these burners are safe
and highly efficient. It is equipped with
a steel flange which slips on the burner
head. When fastening the burner to the
boiler it is necessary to correctly posi-
tion the flange so that the burner head
enters the combustion chamber to the
extent specified by the boiler manufac-
turer.The burner has an electronic
cam mod. MPA 22. The microproces-
sor-controlled MPA 22 provides inter-
mittent operation, controls and moni-
tors
the electronically-modulated fan-equip-
ped 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 in-
structions in the attached manual, code
0006080905).
Operation of is of the progressive
two-stage type, so called because the
switch from primary flame to secondary
flame (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 sufficient, 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 ope-
ned the ignition transformer is switched
off. The burner is now on at the ignition
point (P0). The flame is detected by the
relative control device (an ionisation
sensor positioned inside the flame).
The programming relay goes beyond
the shutdown position and powers the
O F
air/gas delivery regulation servomotors,
which go to minimum (P1). If the 2nd
stage boiler thermostat (or 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 in-
crease is the delivery of gas and com-
bustion air until the maximum flow 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 combu-
stion air and gas servomotors ac-
cording to a pre-set curve.
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 servomotors 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 va-
lue.
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
30 / 59
000608044 _200705
Legend:
1 - Main switch on/off
2 - Thermostats line switch
3 - Display MPA 22
4 - Interference confirm or elimination button
5 – Fuse
burner will star up again, according to
the programme previously described.
During normal operations, the boiler
thermostat (or pressure switch) of the
2nd stage fitted to the boiler detects the
variations requested and automatically
proceeds with adapting the fuel and
combustion air delivery by inserting the
servomotors which regulates delivery
(gas/air). This will rotate in such a way
as to obtain an increase or a decrease.
With this manoeuvre, the gas/air delive-
ry regulating system try's to equilibrate
the quantity of heat supplied to the boi-
ler with that which the boiler gives to
be utilised.
If the flame 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
(3) error message 25H) on display.).
To "unblock" the equipment press the
interference elimination button for
about half a second (4).
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