baltur BT 75 DSPG Manual De Mantenimiento, Uso E Instalación página 17

and therefore its average yield is normally higher even when
the CO value is slightly inferior. It should be remembered
2
that, in order to regulate properly, the water in the system
should be at the right temperature and the burner should have
been operating for at least 15 minutes. If the appropriate
instruments are not available, judgement can be based on the
colour of the flame. We advise regulating in such a way as to
obtain a flame bright orange in colour. Avoid a red flame with
smoke in it, or a white flame with an exaggerated excess of air.
After having checked the fuel/air regulation, tighten the locking
screws of the adjustable screws.
19) Now check if the modulation is functioning correctly in the
automatic mode by moving the AUT - 0 - MAN switch to the
"AUT" position and the MIN - 0 - MAX switch "0". In this way
the modulation is connected only by means of the automatic
control of the boiler probe if we have a modulating burner or
by means of a commend coming from 2° stage thermostat or
pressure switch if we have a two progressive stage burner (BT...
DSPG).
20) Check the efficiency of the flame detection device (photore-
sistance).The photoresistance is a flame control device and,
if the flame should be extinguished during operations, it must
be capable of intervening (this control should be made at least
one minute after start up). The burner should be capable of
blocking itself (shut down), and remaining so; if the flame does
not appear regularly during the start up phase within the time
limit preset on the control box.The shut down causes an imme-
diate interception of the fuel, the burner comes to a standstill
and the red warning light comes on. To check the efficiency of
the photoresistance and of the shut down system, proceed as
follows:
a) start up the burner
b) after about one minute, extract the photoresistant cell by
pulling it out of its seat and simulate flame failure (using a
hand or a rag to close the window in the photoresistance
support). The flame should be extinguished.
c) Keep the photoresistant cell in the dark and the burner will
start up again but, as the photoresistance does not see the
light, the burner will go to shut down within the time preset
on the control box's programme. The control box can only
be unblocked by pressing manually on the appropriate push-
button. To check the efficiency of the shut down device; carry
out this control at least twice.
21) Check the efficiency of the boiler's thermostats or pressure
switches (this operation should stop the burner.
REGULATION OF THE COMBUSTION HEAD
The burner is equipped with a combustion head which can be regu-
lated (by moving it backwards or forwards) in such a way as to close
more or open more the air passage between the disk and the head.
By throttling the passage, it is possible to achieve high pressure
upstream the disk, and therefore high velocity and air turbulence for
low inputs as well. High velocity and air turbulence ensure a better
penetration in the fuel and are therefore an optimum mixture and
allow the burner to operate with good flame stability.
High air pressure, upstream the disk, might be necessary in order to
avoid flame pulsation's, and it is considered practically indispensable
when the burner is operating with a pressurized furnace and/or
high thermal load. It is evident from the above, that the position of
the device which regulates the air on the combustion head should
be put in such a position as to always obtain a decidedly high air
pressure value behind the disk.
It is advisable to regulate in such a way as to achieve a throttling
of the air between of the air shutter which regulates the flow to the
burner's fan suction. Obviously these adjustments should be carried
out when the burner is operating at maximum delivery desired. In
practice, commence regulating with the combustion head in an in-
termediate position, start up the burner and make a first adjustment
as previously described.
When maximum delivery desired has been reached, proceed with
correcting the position of the combustion head; move it backwards
and forwards in such a way as to obtain an air flow suitable for the
light oil delivery with the air regulation in suction considerably open.
In the combustion head is pushed forwards (which causes a reduc-
tion in the air passage between the head and the disk), avoid closing
it completely. When regulating the combustion head, proceed with
centring it perfectly with respect to the disk. It must be pointed out
that, if perfect centring with respect to the disk is not obtained, bad
combustion and excessive heating of the head could occur which
would result in its rapid deterioration.
A control can be carried out by looking through the spy hole situated
on the back of the burner; then tighten home the screws that lock
the combustion head in position.
Make sure that the ignition is correct because if the
!
regulator has been moved forward, it may happen that
the speed of the exiting air is so high that it impairs the
ignition. If this occurs, gradually move the regulator
backward until it reaches a position which allows to
have a regular ignition and set this position as final.
Remember furthermore that for the 1° flame it is re-
commended to limit the amount of air to the minimum
required amount in order to have a safe ignition even
in the most complicated conditions.
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