baltur COMIST 180 DSPNM User Instruction Manual page 25

• Open the regulator integrated in the ignition (pilot) flame valve
as necessary. If the burner is already working with fuel oil, do
not change the position of the air gate, but adjust the quantity of
gas to the air already set for the fuel oil. If, otherwise, the burner
is working with gas only, check the position of the combustion
air adjustment gate and correct it, if necessary, by acting on the
adjustment disc screws.
• Remove the protection cover from the disk carrying the air and
gas flow regulator screws and slacken the screws that block
the regulator screws.
• With burner switch to "O" and master switch turned on, manually
close the remote control and check that the motor revolves in
the correct direction. If necessary, change the position of the
two cables in the line that feeds the motor in order to invert the
direction of revolution.
• Now turn the panel switch on and turn modulator switches to
the MIN (minimum) and MAN (manual) position. This powers
on the control device, and the programmer turns on the burner
as described in the chapter "Operation description". During pre-
ventilation, make sure that the air pressure switch changes its
status (from the closed position without pressure measurement
to the closed position with pressure measurement). If the
pressure switch does not detect sufficient pressure (and does
not change status), neither the transformer nor the pilot flame
gas valve are activated and the equipment locks out. However,
an occasional lock-out during the first stage of ignition is normal,
as air is still present in the valve train pipeline. The air must be
vented to obtain a stable flame. To release, press the "reset" key.
• UV PHOTOCeLL
If the flame is detected by the UV photocell remember what
specified below. A slight amount of grease will strongly compromise
the passage of the ultraviolet rays through the UV photocell bulb,
preventing the internal sensitive element from receiving the
quantity of radiations required for proper operation. If the bulb is
fouled with diesel, fuel oil, etc... it must be properly cleaned. Even
contact with the fingers can leave a slight greasy film, enough
to affect the function of the UV photocell. The UV photocell
does not "detect" daylight or the light from a common lamp.
Its sensitivity can be tested using a flame (lighter, candle) or
the electric discharge that occurs between the electrodes of a
common ignition transformer. To ensure a proper operation, the
UV photocell current value must be sufficiently stable and not go
below the minimum value required for the specific equipment.
It may be necessary to tentatively find the best position by
sliding (axial or rotational movement) the casing that contains
the photocell with respect to the fastening clamp. This can be
checked by connecting a micro-ammeter, with a suitable scale,
in series to one of the two UV photocell connection cables.
Obviously the polarity (+ and -) must be respected. The photocell
current value required for a correct operation of the equipment
is indicated in the wiring diagram.
• With the burner working at the minimum output (open ignition
flame and safety valves, and fuel/air output adjustment
servomotor at its minimum) it is necessary to visually check
the entity and aspect of the flame, and adjust if necessary
(work on the gas supply regulator of the pilot ignition flame).
Afterwards, check the quantity of supplied gas indicated on the
meter, see chapter "Meter reading". If necessary correct the
gas output by acting on the flow rate regulator integrated in the
pilot ignition valve. Then check the combustion with the suitable
instruments. For a correct air/gas ratio, the carbon dioxide (CO
value must increase as the output increases, by nearly 8% at
the burner minimum output for natural gas, up to 10% for the
maximum output. We recommend that the value of 10% should
not be exceeded, as operation in too limited an excess of air can
give rise to unacceptable carbon monoxide (CO) levels (due to
variations in atmospheric pressure, or dust deposits in the air
lines). It is necessary to use a suitable instrument to check that
the carbon monoxide (CO) percentage in the smoke does not
exceed the maximum allowed value of 0.1%.
• After having regulated the "minimum", put the modulation
switches in the "MAN" (manual) and "MAX" (maximum) positions.
• The output adjustment servomotor (fuel/air) starts moving: wait
for the disk (on which the adjustable screws are fitted) to sweep
through an angle of about 12° (this corresponds to the space
taken up by three screws) and then stop modulation by turning
the switch back to position "0".
Cam "V" of the fuel/air output adjustment servomotor
(see 8562/1) activates almost immediately when the
main gas valve completely opens. Gas distribution is
not determined by the main valve but by the position
of the gas distribution adjustment valve (see 8813/1).
Make a visual check on the flame and if necessary regulate
gas and air throughput rates using the regulator screws on
the regulation disk.
• The operation above must be progressively repeated making
the disc turning by approx. 12° each time, and adjusting, if
necessary, the gas and air output along the modulation stroke.
Make sure that the gas output is progressive and gradual, and
to have the maximum output at the end of the modulation stroke.
This condition is necessary to ensure that modulation operation
is gradual enough. Change the fuel control screw positioning in
order to fulfil the above-mentioned condition.
• Then, with burner at the maximum output required by the boiler,
check the combustion with suitable instruments and, in case,
correct the adjustment previously carried out with a visual
inspection only. (CO
• It is recommended to check combustion also in some
intermediate points along the modulation stroke, using the
specific tools and, if necessary, modify the previous setting
made after a visual check only.
• Now check that modulation works properly in automatic mode.
Turn the AUT - O - MAN switch to "AUT" and the MIN - O - MAX
switch to "O". In this way the modulation is exclusively enabled
by the boiler probe automatic control, in case the burner is in
MODULATION mode, or by the thermostat or the second stage
pressure switch control in case the burner is of the TWO-STAGE
PROGRESSIVE type. See booklet "Electronic regulator" only
for the modulating model.
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max. = 10% - CO max. 0.1%).
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