Baltur btg 15 me Instruction - page 32
30 / 68
000608220_2007/03
D E S C R I P T I O N O F
O P E R AT I O N S AT T W O
STAGE PROGRESSIVE
Theseburnersareoftheblownairtype
whichhaveamixtureofgas/airatthe
combustionhead.Theyaresuitablefor
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
andhighlyefficient.Itisequippedwith
asteelflangewhichslipsontheburner
head.Whenfasteningtheburnertothe
boileritisnecessarytocorrectlyposi-
tiontheflangesothattheburnerhead
enters the combustion chamber to the
extentspecifiedbytheboilermanufac-
turer.The burner has an electronic
cam mod. MPA 22. The microprocessor-
controlled MPA 22 provides intermittent
operation, controls and monitors
theelectronically-modulatedfan-equip-
pedgasburnersandfeaturestwo(air/
gas)adjustermotors.Whenworking
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).
Operationofisoftheprogressivetwo-
stagetype,socalledbecausetheswitch
fromprimaryflametosecondaryflame
(from minimum to the set maximum)
occursgraduallyasregardsthedelive-
ryofbothcombustionairandfuel;this
gives considerable advantages in terms
ofthepressurestabilityinthegasfeed
line. Delivery rate ranges, approxima-
tely,from1to1/3.Ignitionispreceded
by pre-ventilation of the combustion
chamberasperstandards,withtheair
open: this lasts about 36 seconds. If, at
the end of the ventilation stage, the air
pressure switch detects that pressure
issufficient,theignitiontransformerco-
mesonand,after3seconds,thesafety
and main valves open in sequence.
The gas reaches the combustion head,
ismixedwiththeairbeingdeliveredby
the fan, and is ignited. Delivery is re-
gulatedbythegasthrottlevalve.Three
seconds after the (main and safety)
valves are opened the ignition tran-
sformer is switched off.The burner is
nowonattheignitionpoint(P0).The
flameisdetectedbytherelativecontrol
device (an ionisation sensor positioned
insidetheflame).Theprogrammingre-
laygoesbeyondtheshutdownposition
andpowerstheair/gasdeliveryregula-
tionservomotors,whichgotominimum
(P). If the 2nd stage boiler thermostat
(or pressure switch) – adjusted by a
temperature or
pressure greater than that in the boiler)
allow,theair/gasdeliveryservomotors
start running and cause a gradual in-
creaseisthedeliveryofgasandcom-
bustionairuntilthemaximumflowrates
towhichtheburnerhasbeensethave
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
pressureswitch)ofthe2ndstageand
makestheservomotorsregulatinggas/
airdeliveryrotateintheoppositesense
ofdirection.Thusgasdeliveryandthe
relative combustion air are gradually
reduceduntiltheyreachminimumva-
lue.
Even with delivery at a minimum, if
the limit (temperature or pressure at
the shut down device (thermostat or
pressureswitch)hasbeenregulatedis
reached,theburnerwillbebroughtto
a standstill. When the temperature or
pressure drops below the intervention
limitsetontheshutdowndevice,the
burnerwillstarupagain,accordingto
the programme previously described.
During normal operations, the boiler
DISPLA
Y.TIFF
thermostat(orpressureswitch)ofthe
2ndstagefittedtotheboilerdetectsthe
variationsrequestedandautomatically
proceeds with adapting the fuel and
combustionairdeliverybyinsertingthe
servomotors which regulates delivery
(gas/air).Thiswillrotateinsuchaway
as to obtain an increase or a decrease.
Withthismanoeuvre,thegas/airdelive-
ryregulatingsystemtry’stoequilibrate
thequantityofheatsuppliedtotheboi-
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”(theburnerstopscompletelyand
(1)errormessage25H)ondisplay.).
To “unblock” the equipment press the
interference elimination button for
about half a second (2).