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6.8.1
Burner calibration procedure
After making a first ignition, verify the correct operation at the de-
sired output. If this is not so, calibrate the gas cam.
With the optimal adjustment obtained, remember to lock the ad-
justment screws of the cam profiles by means of screws
3)(Fig. 29).
6.9
Pressure switch adjustment
6.9.1
Air pressure switch - check CO
Adjust the air pressure switch after performing all other burner
adjustments with the air pressure switch set to the start of the
scale (Fig. 31).
With the burner operating at MIN output, increase adjustment
pressure by slowly turning the relative knob clockwise until the
burner locks out.
Then turn the knob anticlockwise by about 20% of the set point
and repeat burner start-up to ensure it is correct.
If the burner locks out again, turn the knob anticlockwise a little
bit more.
In conformity with the standard, the air pressure
switch must prevent the air pressure falling below
80% of the adjusted value and the CO in the flue
gases exceeding 1% (10,000 ppm).
WARNING
To check this, insert a combustion analyser into
the chimney, slowly close the fan suction inlet (for
example with cardboard) and check that the burn-
er locks out, before the CO in the fumes exceeds
1%.
The air pressure switch is installed in "absolute" position, that is
connected only to the pressure test point "+" 22)(Fig. 4).
6.9.2
Maximum gas pressure switch
Adjust the maximum gas pressure switch (Fig. 32) after making
all other burner adjustments with the maximum gas pressure
switch set to the end of the scale.
To calibrate the maximum gas pressure switch, open the tap and
then connect a pressure gauge to its pressure test point.
The maximum gas pressure switch must be regulated to a value
no higher than 30% of the measurement read on the gauge when
the burner is working at maximum output.
After making the adjustment, remove the pressure gauge and
close the tap.
6.9.3
Minimum gas pressure switch
Adjust the minimum gas pressure switch after performing all the
other burner adjustments with the pressure switch set to the start
of the scale (Fig. 33).
With the burner operating at maximum output, increase adjust-
ment pressure by slowly turning the relative knob clockwise until
the burner stops.
Now turn the knob anticlockwise by 0,2 kPa (2 mbar) and repeat
burner start-up to ensure it is uniform.
If the burner locks out again, turn the knob anticlockwise again by
0,1 kPa (1 mbar).
Start-up, calibration and operation of the burner
During the calibration of the cam, do not exceed
the travel limits of the servomotor 0 ÷ 130 to avoid
sticking.
WARNING
Check, again with a manual operation 0-130 of the
cam, there are no mechanical stops before the acti-
vation of the micro-switches 1-2 of the servomotor.
D3856
1 kPa = 10 mbar
WARNING
27
GB
D3854
Fig. 31
PA
20181543
PGM
Fig. 32
D3855
Fig. 33
20145860
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