baltur GI MIST 350 DSPGM User Instruction Manual page 23

a suitable scale, in series to one of the two UV photocell connection
cables. Obviously the polarity (+ and -) must be respected.
The ionization current value required for a correct operation of the
equipment is indicated in the electric 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
output increases, by nearly 8% at the burner minimum output for
natural gas, up to 10% for the maximum output.
Do not exceed 10% of CO2 to avoid working with a low
quantity of air leading to an increase in the smoke opacity for
atmospheric pressure variations, dust deposits in the fan air
ducts, etc.. causing an increase in CO (carbon monoxide).
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 adjusted the "minimum" output, adjust the burner
maximum output. Turn the modulation switches to "MAN"
(manual) and "MAX" (maximum).
• The fuel/air adjustment servomotor starts. Wait for the disc
with the adjustment screws to perform an angle of nearly 12°
(corresponding to the space of three screws) and turn the
switch to "0" to stop the modulation. Visually check the flame
and, if necessary, adjust the air and gas output by acting on the
adjustment disc screws to obtain an efficient combustion. The
operation above must be progressively repeated making the
disc turning by ca. 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 a good flame modulation.
• 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 max. = 10% - CO max. 0.1%).
2
• Use suitable instruments to check the combustion in some
intermediate points along the modulation stroke and, if
necessary, correct the previously carried out adjustment.
• Check the modulation automatic operation turning the switch
to AUT - or - MAN to "AUT" and the switch MIN - or - MAX to
"O". In this way the modulation is exclusively adjusted by the
electronic regulator controlled by the boiler probe, or by the 2nd
stage thermostat or pressure switch control in case the burner
is of the a two-stage progressive type.
) value must increase as the
2
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Usually it is not necessary to act on the modulation electronic
regulator internal settings. To customise them, please consult
the QUICK ELECTRONIC REGULATOR GUIDE supplied
with the system.
• The air pressure switch makes the equipment safe (block) if
the air pressure is not at the expected value. The pressure switch
must be set to close the contact which should be closed during
the operation, when the air pressure in the burner reaches
the sufficient value. The pressure switch connection circuit
foresees a self-check, so the contact that is should be closed
in stand-by (no air pressure in the burner), must actually create
this condition, otherwise the command and control equipment
will not be activated and the burner will not start-up. If the
contact which should be closed during operation (insufficient
air pressure) does not close, the equipment performs its check
cycle but the ignition transformer is not activated, and the gas
valves do not open, causing the burner to shutdown. To ensure
the air pressure switch correct operation, with burner at the
minimum output, increase the adjustment value until reaching
the triggering value which must be followed by the immediate
burner shutdown. Press the release button to resume the burner
operation, and set the pressure switch to a sufficient value to
detect the air pressure during the pre-ventilation phase.
• The gas pressure control switches (minimum and maximum)
prevent the burner from operating when gas pressure is not
between the expected range. The specific function of the
pressure control switches clearly reveals that the pressure switch
for controlling minimum pressure must use the contact which is
closed when the pressure switch detects a pressure value above
the value it is set to; on the other hand, the pressure switch
for controlling maximum pressure must use the contact that is
closed when the pressure switch detects a pressure lower than
the value it is set to. The minimum and maximum gas pressure
switches must be set when testing the burner, on the basis of
the pressure measured in each case. The pressure switches
are connected in series, so the triggering (circuit opening) of
any of them, does not allow the equipment, and so the burner,
to start. When the burner is working (flame on), tripping of the
gas pressure switches (opening the circuit) will shut down the
burner immediately. When testing the burner, it is very important
to check that the pressure switches are working properly. With
appropriate regulation of the regulation components, we can be
sure that the pressure switch will be tripped (opening the circuit)
and shut down the burner.