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7.7.3
MIN burner output
Min output must be selected within the firing rate range shown on
page 11.
Press button 2)(Fig. 39 at page 29) "output reduction" until the
servomotor has closed the air gate valve and the gas butterfly
valve to 30° (factory set adjustment).
Adjusting gas delivery
Measure the delivery of gas from the gas meter.
If this value is to be reduced, decrease the angle of cam III
(Fig. 41) slightly by proceeding a little at a time until the
angle is changed from 30° to 28° - 26°....
If it has to be increased press the button "output increase"
2)(Fig. 39 at page 29) (i.e. open the gas butterfly valve by
10-15°), increase the cam III angle (Fig. 41) with small suc-
cessive movements, i.e. take it from angle 30° to 32° - 34°...
Then press the button "output decrease" until the servomo-
tor is taken to the minimum opening position and measure
the gas delivery.
Note
The servomotor follows the adjustment of cam III only when the
cam angle is reduced.
If it is necessary to increase the cam angle, first increase the ser-
vomotor angle with the key "output increase", then increase the
cam III angle, and finally bring the servomotor back to the MIN
output position with the key "output decrease".
In order to adjust cam III, especially for fine movements, the
key 10)(Fig. 41), held by a magnet under the servomotor,
can be used.
Adjustment of air delivery
Progressively adjust the starting profile of cam 4)(Fig. 40) by turn-
ing the screws 5).
It is preferable not to turn the first screw since this is used to set
the air gate valve to its fully-closed position.
D1710
Key Fig. 40
1
Servomotor
2
Servomotor 1) - Cam 4): engaged
3
Servomotor 1) - Cam 4): disengaged
4
Adjustable profile cam
20034985
Start-up, calibration and operation of the burner
Fig. 40
5
Cam starting profile adjustment screws
6
Adjustment fixing screws
7
Cam end profile adjustment screws
8
Graduated sector for gas butterfly valve
9
Index for graduated sector 8
10 Key for cam III adjustment
7.7.4
Intermediate outputs
Adjustment of gas delivery
No adjustment of gas delivery is required
Adjustment of air delivery
Press the key 2)(Fig. 39 at page 29) "output increase" a little so
that the servomotor turns by about 15°.
Adjust the screws until optimal combustion is obtained. Proceed
in the same way with the other screws.
Take care that the cam profile variation is progres-
sive.
WARNING
Switch off the burner using switch 1)(Fig. 39 at page 29), at
OFF position;
disengage the cam 4)(Fig. 40) from the servomotor, by
pressing the button 3)(Fig. 41);
moving it to the right, and check more than once that the
movement is soft and smooth, and does not grip, by rotating
the cam 4) forward and backward by hand.
Engage the cam 4) to the servomotor again by moving the
button 2)(Fig. 41) to the left.
As far as is possible, try not to move those screws at the
ends of the cam that were previously adjusted for the open-
ing of the air gate to MAX and MIN output.
Finally fix the adjustment by turning the screws 6)(Fig. 40).
N.B.
Once you have finished adjusting outputs MAX - MIN - INTER-
MEDIATE, check ignition once again: noise emission at this
stage must be identical to the following stage of operation.
If you notice any sign of pulsations, reduce the ignition stage de-
livery.
30
GB
D889
Fig. 41
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