baltur SPARKGAS 30 LX Betriebsanleitung Seite 29

19) Now, check the correct automatic modulation operation.
20) The air pressure switch has the function of locking the control box if the air pressure is not correct. The pressure
switch must thus be set to start by closing the contact (a normally open contact) when air pressure in the burner
reach a sufficient value.
Note that if the normally open contact does not close (insufficient air pressure), the control box performs its cycle
but the ignition transformer does not start, the gas valves do not open and as a consequence, the burner stops in
lock. To check the correct operation of the air pressure switch, set the burner to the minimum output, increase
the regulation value so as to check when it should start to immediately "lock" the burner. Unlock the burner by
pressing the special push button and restore the pressure switch regulation to a sufficient value to detect the
existing air pressure during the pre-ventilation step.
The pressure switch connection circuit provides for the automatic control; thus, the contact provided to be closed
when at rest (fan off, and thus, absence of air pressure in the burner) must implement this condition, or the control
box does not start (the burner remains off).
21) The gas pressure control switches (minimum and maximum), if installed, have the function of preventing the
burner from operating when gas pressure does not range in the expected values. From the specific function of the
pressure switches, it is evident that the minimum pressure control switch must used the contact that is closed
when it detects a higher pressure than that to which it is set, the maximum pressure control switch must use the
contact that is closed when it detects a lower pressure than that to which it is set. Therefore, the gas maximum
and minimum pressure switch regulation must be performed during the burner general test and inspection, based
on the pressure measured each time. Pressure switches are electrically connected in series; thus, the start (in-
tended as circuit opening) of any one of the gas pressure switches does not allow starting the control box and thus,
the burner. When the burner is operating (flame on), the start of the gas pressure switches (circuit opening)
causes the immediate shut down of the burner. Upon the general test and inspection of the burner, it is necessary
to check the correct operation of the pressure switches. By suitably acting on the respective regulation members,
make sure that the pressure switch starts (circuit opening), thus shutting down the burner.
22) In case of UV photoelectric cell, after at least one minute from ignition extract the photoelectric cell from its
housing. When the UV photoelectric cell is extracted from its housing, it cannot "see" the ultraviolet radiation
emitted by the flame and thus, the relevant relay de-energises. The burner immediately shuts down in "lock". A
light greasiness strongly affects the passage of ultraviolet beams through the UV photoelectric cell bulb, thus
preventing the internal photosensitive element from receiving the necessary radiation for a correct operation. If the
bulb is dirty with light oil, heavy oil, etc., clean it accurately. Note that a simple finger contact can cause a light
greasiness, sufficient to impair the UV photoelectric cell operation. The UV photoelectric cell does not "see"
daylight or the light of a common candle. A possible sensibility check can be made with a flame (lighter, candle) or
with the electrical discharge occurring between the electrodes of a common ignition transformer. To ensure a
correct operation, the UV photoelectric cell current value must be sufficiently stable, and must not decrease below
the minimum 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).
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