baltur COMIST 180 DSPNM User Instruction Manual page 22

• 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 "O". Visually check the flame and
adjust the combustion air, if necessary, following the instruction
at the previous point. Then, use the appropriate instruments
to check combustion and, if necessary, modify the previous
setting after a visual check only. The operation above must be
progressively repeated making the disc turning by approx. 12°
each time, and adjusting, if necessary, the fuel/air ratio along
the modulation stroke. Make sure that the progression in the
maximum delivery occurs at the end of the modulation. This
condition is necessary to ensure that modulation operation
is gradual enough. If necessary, change the position of the
screws controlling fuel throughput to obtain this result. The
maximum output is obtained with a return pressure approx.
2 ÷ 3 bar lower than the delivery one (usually 20 ÷ 22 bar).
For a correct air/fuel ratio the detected value of carbon dioxide
(CO ) must increase as the output increases, indicatively at least
2
10 % at the minimum output up to the best value of nearly 13 %
at the maximum output. It is inadvisable to exceed a CO
13% so as to prevent operation with a rather limited excess of air,
which could lead to a significant increase in smoke opacity due
to unavoidable causes (changes in atmospheric pressure, small
dust deposits in the fan air ducts etc.). Smoke opacity is strictly
connected to the type of fuel used (the most recent provisions
regarding this matter indicate no. 6 in the Bacharach scale as
maximum value). We recommend that you keep smoke opacity
at a value lower than 2 in the in the Bacharach scale even if
the CO value could consequently be slightly lower. Reduced
6
opacity soils the boiler less and the average efficiency of the
latter is normally higher even if CO
Remember that to achieve a proper adjustment the system water
temperature must be at the normal working temperature and that
the burner must have been working for at least 15 minutes. If
the appropriate instruments are not available, judgement can
be based on the colour of the flame. We recommend that the
adjustment is performed so as to obtain a soft light orange
flame; avoid red flames with smoke and white flames with an
exaggerated excess of air. After making sure that the air/fuel
mixture is correct, tighten the adjustment screws retainers.
• 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 modulation activates exclusively with
the boiler probe automatic command if the burner belongs to
the MODULATING model, or with the second stage thermostat
or pressure switch command if the burner belongs to the
TWO-STAGE PROGRESSIVE model, (see booklet "Electronic
regulator" only for the modulating model).
• Check that the pre-heater thermostat regulation
does not cause anomalies (bad ignition, presence of
smoke, build up of gas in the pre-heaters, etc.).
If necessary change these values either up or down,
remembering that the regulation thermostat, must however be at
•
figure of
2
levels are slightly lower.
2
•
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a temperature 15 ÷ 20°C higher than that to which the minimum
level thermostat has been set. The minimum thermostat should
switch on at the minimum temperature necessary to obtain good
atomisation (viscosity at nozzle not higher than 2° E). Use as
a template the viscosity-temperature diagram corresponding to
the type of oil used.
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. Please note that simple contact with your fingers can
leave a slight amount of grease that is enough to compromise
the operation of the UV photocell. The UV photocell does not
"see" daylight nor does it perceive the light of an ordinary
lamp. Sensitivity can be checked with a flame (cigarette lighter,
candle) or with the electric discharge 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. Check the flame detector
efficiency (UV photocell). The flame detecting UV photocell must
be able to trigger upon system operation if the flame turns off
(this check must be carried out after at least one minute from
the ignition). The burner should be capable of blocking itself
(shut down), and remaining so; if the flame does not appear
regularly during the start up phase within the time limit preset
on the control box. The lock condition leads to an immediate
fuel shut-off, the system stops and the lock warning light comes
on. To check the UV photocell and lock, proceed as follows:
- Start the burner
- After at least one minute from ignition remove the UV photocell
from its seat, and simulate a flame failure. The burner flame
must turn off, the equipment will immediately shut down in
"lock" condition.
- The equipment can only be released manually by pressing
the release button. The shutdown efficiency test must be
performed at least twice.
Check that the boiler thermostats or pressure switches are
operating correctly (they must cause the boiler to shut down
when they intervene).