baltur BTG 20 LX Instructions For Use Manual page 42

of ultraviolet beams through the UV photoelectric cell bulb, thus
E
preventing the internal photosensitive element from receiving
the necessary radiation for a correct operation. If the bulb is
N
dirty with light oil, heavy oil, etc., clean it accurately. Note that a
simple finger contact can cause a light greasiness, sufficient to
G
impair the UV photoelectric cell operation. The UV photoelectric
cell does not "see" daylight or the light of a common candle. A
L
possible sensibility check can be made with a flame (lighter,
I candle) or with the electrical discharge occurring between the
electrodes of a common ignition transformer. To ensure a cor-
S
rect operation, the UV photoelectric cell current value must be
sufficiently stable, and must not decrease below the minimum
H
value required for the specific control box. Said value is shown
in the wiring diagram. It may be necessary to experimentally
search the best position by making the body containing the
photoelectric cell slide (axial or rotation movement) with respect
to the fixing clamp.
23) Check the efficiency of the boiler thermostats or pressure
switches (their start must shut down the burner).
AIR REGULATION ON COMBUSTION HEAD
Warning: When, as in this case, the burner is provided with gas
valves model MB-VEF...., by moving the air regulation device on
the combustion head there automatically and unavoidably occurs
a gas output variation (see chapter Valve operation principle, model
MB-VEF...).
The combustion head is equipped with a regulation device, so as to
open or close the air passage between disk and head. By closing
the passage, it is thus possible to obtain a high pressure upstream
of the disk also for low flow rates. The high air speed and turbulence
allows a better penetration of the same into the fuel and therefore,
an excellent mixture and flame stability. It may be necessary to have
a high air pressure upstream of the disk, so as to prevent flame
pulses. This condition is indispensable when the burner operates
on pressurised combustion chamber and/or with high heating load.
From what said above it is evident that the device closing the air
on the combustion head must be set to such position as to always
obtain, behind the disk, a very high air pressure value. It is advisable
to regulate so as to have such air closure on the head as to require
the opening of the air damper regulating the flow of the burner
ventilator suction. Of course, this condition must only occur when
the burner is operating at the maximum desired output.
In practice, the regulation must start with the device that closes the
air on the combustion head in an intermediate position, igniting the
burner for an indicative regulation as explained above.
When the maximum desired output is reached, correct the position of the
device closing the air on the combustion head by moving it forwards or
backwards (0002934190) so as to have a suitable air flow for the output,
with suction air regulation damper sensibly open.
N.B. To facilitate the combustion head regulation, see table (n°
0002934170).
When reducing the air passage on the combustion head, avoid closing
it completely, which may cause an excessive heating of the
head with a consequent quick deterioration.
N.B. Check that ignition is regular because if the controller has
been moved forward, the output air speed could be so high
as to make ignition difficult. In such a case, it is necessary to
move backwards, degree by degree, the regulator until rea-
ching the position in which the ignition is regular and accept
this new position as definitive. We still remind you that it is
preferable, for the small flame, to limit the air quantity to the
minimum indispensable to have a safe ignition even in the
most demanding case.
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0006080937_2010/03