baltur COMIST 180 DSPNM Mode D'emploi page 21

necessary to ensure efficient combustion. Tighten more
or loosen more the adjusting screws in correspondence
to the point of contact, with the lever which transmits
the movement to the combustion air regulation shutter.
It is preferable that the quantity of air for the "minimum" is
slightly reduced, in order to ensure a soft ignition even in the
most critical conditions.
19) After having regulated the air for the "minimum", put the modu-
lation switches in the "MAN" (manual) and "MAX" (maximum)
positions.
20) The servomotor which regulates delivery (fuel/air) starts
moving; wait until the disk on which the regulating screws
have been fitted, has reached an angle of about 12° (this
corresponds to the space taken up by three screws), stop
modulation and return the switch to the "O" position. Carry out
a visual control of the flame and proceed, if necessary, with
regulating the combustion air by operating as described in point
18. Subsequently, control combustion with the appropriate
instruments and modify, if necessary, the previous regulation
carried out by visual control only. The operation described
above should be repeated progressively (by moving forwards
the disk by about 12° at a time) and modifying every time, if
necessary, the fuel/air ratio during the entire modulation run.
Make sure that the increase in fuel delivery occurs gradually
and that maximum delivery is reached at the end of the modu-
lation run. This is necessary in order to ensure that modulation
functions with good graduality. The positions of the screws that
commend the fuel may need to be modified in order to obtain
the graduality required. Maximum delivery is obtained when
the return pressure is about 2 ÷ 3 bar less that the delivery
pressure (normally 20 ÷ 22 bar). For a correct air/fuel ratio,
the percentage of Carbon Dioxide (CO
the increase in delivery (about a minimum of 10% at minimum
delivery to a maximum of 13% at maximum delivery. We advise
against exceeding 13% of the CO
rather limited excess of air which would cause a considerable
increase in smoke opacity due to unavoidable circumstances
(a variation in the atmospheric pressure; presence of dust
particles in the fan's air ducts, etc.). Smoke opacity depends
on the type of fuel utilized (the most recent provisions indicate
that it should not exceed N° 6 of the Bacharach Scale). We
advise, if possible, maintaining smoke opacity below N° 6 of
the Bacharach Scale even if, as a consequence, the CO
is slightly lower. The lower smoke opacity dirties the boiler less
and therefore its average yield is normally higher even when
the CO value is slightly inferior. It should be remembered that,
2
in order to regulate properly, the water in the system should
be at the right temperature and the burner should have been
operating for at least 15 minutes. If the appropriate instruments
are not available, judgement can be based on the colour of the
flame. We advise regulating in such a way as to obtain a flame
bright orange in colour. Avoid a red flame with smoke in it, or
a white flame with an exaggerated excess of air. After having
checked the air/fuel regulation, tighten the locking screws of
the adjustable screws.
21) Control that the modulation motor functions automatically by
putting the AUT - O - MAN switch in the "AUT" position and
All manuals and user guides at all-guides.com
22) Check that regulation of the pre-heater's thermostat does not
23) UV CELL
) should increase with
2
to avoid operating with a
2
value
2
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the MIN - O - MAX switch in the "O" position. In this way, mo-
dulation is activated exclusively by the automatic command of
the boiler's probe, if the burner a modulating version, or on the
command of the thermostat or pressure switch of the 2nd stage,
if the burner is a two stage progressive version. (See Chapter
"Electronic Potentiality Regulator RWF 40 for the modulating
version).
cause any defects (bad ignition, smoke presence, formation of
gas in the pre-heater, etc.). If necessary, higher or lower these
values keeping in mind that the thermostat should be regulated
at a temperature of about 15 ÷ 20 °C higher than that at which
the minimum thermostat is regulated. The minimum thermostat
must close at the minimum temperature indispensable in order
to obtain good atomisation (viscosity at the nozzle should
not exceed 2 °E). For further information, see the Viscosity-
Temperature Diagram with to the type of oil used.
The flame detection is carried out with the UV Cell and the
following should be taken into consideration. Even the slightest
greasiness will compensate the passage of the ultraviolet rays
to the UV photoelectric cell bulb, thus preventing the sensitive
internal element from receiving the quantity of radiation neces-
sary for it to function properly. Should the bulb be fouled by
light oil, fuel oil, etc., it is indispensable to clean it thoroughly.
It should be pointed out that even by simply touching the bulb
with the fingers, it is possible to leave a slight greasiness which
could compromise the working of the UV photoelectric cell. The
UV Cell does not "see" daylight or light from an ordinary lamp.
It is possible to verify its sensibility with a flame (or cigarette
lighter or a candle) or with the electric spark that occurs betwe-
en electrodes in an ordinary ignition transformer. To ensure
that the UV Cell works properly, its current value should be
sufficiently stable so as not to fall below the minimum value
required for the specific control box. It may be necessary to
search experimentally for the best position by sliding (axial or
rotation movement) the body that contains the photoelectric
cell in respect to the fastening clamp. An inspection can be
carried out in inserting a microammeter, with an adequate scale,
in series to one of the two UV photoelectric cell connection
wires. It is obviously necessary to respect polarity ( + e - ).
The value of the cell current to ensure functioning of the control
box is shown on the wiring diagram. Check the efficiency of
the flame detection device (UV Cell). The UV Cell is a flame
control device and, if the flame should be extinguished during
operations, it must be capable of intervening (this control should
be made at least one minute after start up). 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 shut down
causes an immediate interception of the fuel, the burner comes
to a standstill and the red warning light comes on. To check
the efficiency of the UV Cell and of the shut down system,
proceed as follows:
a) start up the burner
b) after about one minute, extract the UV Cell by pulling it out
of its seat and simulateflame failure. The flame should be
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