baltur COMIST 122 DSPGM Manual De Instrucciones página 23

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 the simple contact with
your fingers can leave a slight amount of grease that is enough
to compromise the operation. 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 try to
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 ionization current value required for a correct operation of the
equipment is indicated in the electric diagram.
11) 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
increase as the 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 CO
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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%.
12) After having adjusted the "minimum" output, adjust the burner
maximum output. Turn the modulation switches to "MAN"
(manual) and "MAX" (maximum).
13) 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
) value must
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to avoid working with a low
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have the maximum output at the end of the modulation stroke.
This condition is necessary to ensure a good flame modulation.
14) 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%).
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15) Use suitable instruments to check the combustion in some
intermediate points along the modulation stroke and, if
necessary, correct the previously carried out adjustment.
16) Check the modulation automatic operation by 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.
Usually it is not necessary to act on the modulation
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electronic regulator internal settings. To customise
them, please consult the QUICK cTRON REGULATOR
GUIDE 08 supplied with the system.
17) The air pressure switch must shut-down the equipment when
detecting an air pressure different from the foreseen one. 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.
18) The pressure switches for checking gas pressure (minimum and
maximum) prevent the burner from operating when gas pressure
is not between the expected ranges. The specific function of
the pressure 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, while 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 necessary