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6.6
Burner adjustment
6.6.1
Gas/air delivery adjustment
Slightly move towards the maximum flow rate (butterfly valve
fully open);
adjust the maximum delivery required with the pressure sta-
biliser.
Adjust the fuel parameters with the air servomotor and mem-
orise the maximum combustion value;
slowly complete the procedure, synchronising the combus-
tion with the two servomotors and memorising the different
adjustment values.
For the start-up procedure and the adjustment
of the parameters, see the specific manual of
the electronic cam, supplied with the burner.
WARNING
WARNING
6.7
Final calibration of the pressure switches
6.7.1
Air pressure switch
Adjust the air pressure switch after performing all other burner
adjustments with the air pressure switch set to the start of the
scale (Fig. 43).
With the burner operating at MIN output, insert a combustion
analyser in the stack, slowly close the suction inlet of the fan (for
example, with a piece of cardboard) until the CO value does not
exceed 100 ppm.
Slowly turn the appropriate knob clockwise until the burner goes
into lockout.
Read the value indicated by the upward arrow on the graduated
scale (Fig. 44). Turn the knob clockwise again, until the value
shown on the graduated scale corresponds with the arrow point-
ing downwards, and so recovering the hysteresis of the pressure
switch (shown by the white mark on a blue background, between
the two arrows).
Now check the correct start-up of the burner.
If the burner locks out again, turn the knob anticlockwise a little
bit more.
During these operations it may be useful to measure the air pres-
sure with a pressure gauge.
The connection of the pressure gauge is shown in Fig. 44.
The standard configuration is that with the air pressure switch
connected in absolute mode. Note the presence of a "T" connec-
tion, not supplied.
In certain applications in strong depression situations, the con-
nection of the pressure switch does not allow it to change over.
In this case it is necessary to connect the pressure switch in dif-
ferential mode, applying a second tube between the air pressure
switch and the fan suction line mouth. In this case also, the pres-
sure gauge must be connected in differential mode, as shown in
Fig. 44.
20121288
Start-up, calibration and operation of the burner
6.6.2
Light oil/air delivery adjustment
Position the selector for selecting the light oil fuel.
During the ignition phase, slightly move towards the oil ser-
vomotor, with an approximate adjustment of max. 90°.
Adjust the maximum pressure on the return nozzle using the
"nut and blocking nut".
Adjust the fuel parameters with the air servomotor and mem-
orise the maximum combustion value.
Slowly complete the procedure, synchronising the combus-
tion with the two servomotors.
Memorise the different adjustment values.
D3951
Connecting the
pressure gauge
with the pres-
sure switch in
absolute mode
20053501
Connecting the pressure gauge with the
pressure switch in differential mode
34
GB
D3854
Fig. 43
Fig. 44
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