baltur GI 350 DSPG, Instruction

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18) The servomotor which regulates the fuel/air delivery starts moving; wait until the disk on which the regulating
screws have been fitted, has reached an angle of about 12° (this corresponds to a space taken up by three
screws), stop the modulation and return the switch to the “O” position. Carry out a visual control of the fla-
me and proceed, if necessary, with regulating the combustion air by operating as described in point 16.
Subsequently, control combustion with the appropriate instruments and modify, if necessary, the previous regula-
tion carried out by visual control only. The operation described above should be repeated progressively (by mo-
ving 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 modulation 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 gra-
duality required. Maximum delivery is obtained when the return pressure is about 2 ÷ 3 bar less than the delivery
pressure (normally 20 ÷ 22 bar). For a correct air/fuel ratio, the percentage of Carbon Dioxide (CO
2
) should increase
with the increase in delivery (at least 10% at minimum delivery to a maximum of 13% at maximum delivery).
We advise against exceeding 13% of CO
2
to avoid operating with a rather limited excess of air which could
cause a considerable increase in smoke opacity due to unavoidable circumstances (a variation in the atmo-
spheric 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° 2 of the Bacharach Scale).
We advise, if possible, maintaining smoke opacity below N° 2 of the Bacharach Scale, even if, as a consequen-
ce, the CO
2
value is slightly lower. The lower smoke opacity dirties the boiler less and therefore its average
yield is normally high even when the CO
2
value is slightly inferior. It should be remembered that, 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.
19) The gas pressurestats (minimum and maximum pressure) prevent the burner from operating when gas pressure
is not within planned range. Given the specific functions of these pressurestats, it follows that the minimum
pressure control switch must utilize the contact that is closed when the switch detects pressure higher than its
own setting. The maximum pressure control switch, on the other hand, must utilize the contact that is closed
when the switch detects pressure lower than its own setting. Minimum and maximum gas pressurestats must
be set during burner testing, in relation to the pressure values detected from time to time. The pressurestats are
connected in series, therefore operation (i.e. opening of the circuit) of either one of the switches does not con-
sent switch-on of the equipment. Correct gas pressurestat operation must be checked during burner testing.
By using the adjustment devices, it can be verified whether the pressurestat that must stop the burner (by
opening the circuit) effectively operates.
20) Control that the modulation motor functions automatically by putting the AUT - O - MAN switch in the “AUT”
position and the MIN - O - MAX switch in the “O” position. In this way, modulation is activated exclusively
by the automatic command of the boiler’s probe, if the burner is a GI...MM (modulating) version, or on the
command of the thermostat or pressure switch of the 2nd stage, if the burner is a GI...DSPG (two stage pro-
gressive) version. (See Chapter “Electronic Potentiality Regulator RWF 40 for the modulating version).
Normally, it is not necessary to alter the internal settings of the Potentiality Regulator RWF 40, however, the
relative instructions are contained in the appropriate booklet.
21) Check the efficiency of the flame detection device (Photoresistant Cell). The photoresistant 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 photoresistant cell and of the
shut down system, proceed as follows:
a) Start up the burner
b) after one minute, extract the photoresistant cell by pulling it out of its seat and simulate flame failure with
a dark cloth. The flame should be extinguished and the control box will repeat the ignition phase from the
beginning and, immediately after the flame appears, it will go to shut down.
c) The control box can only be unblocked by pressing manually on the appropriate pushbutton (unblocking).
To check the efficiency of the shut down device, carry out this control at least twice.
22) Check the efficiency of the boiler’s thermostats or pressure switches (this operation should stop the burner).