baltur BGN 200 LX, Maintenance, Use And Installation Manual

Page: 27 / 53

19 / 36
0006081062_200
904
E
N
G
L
I
S
H
AIR REGULATION ON COMBUSTION HEAD
(See dr. n° 0002933310)
I
Warning:
When, as in this case, the burner is provided with gas valves
model MB-VEF.., DMV-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.., DMV-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 so as to have a suitable air flow for the output,
with suction air regulation damper sensibly open
(see dr. n° 0002933310).
!
To facilitate the combustion head regulation, see table (dr.
n° 0002933200)
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. Perfectly adjust to
central position with respect to the disk. Note that if not perfectly
centred with respect to the disk may cause a wrong combustion and
an excessive head heating, with a consequent quick deterioration.
The check is carried out by looking through the inspection hole on
the rear side of the burner. Afterwards, tighten the screws locking the
position of the air regulation device on the combustion head.
!
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 reaching the position in which the igni-
tion 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.
The minimum ionisation current for the control box to run is 6
µA. The burner flame generates a markedly higher current that
will not normally require any control box checks.
If you want to measure the ionisation current you have to con
-
nect a milliammeter in series to the ionisation electrode cable,
opening connector “C” (see diagram).