D729
1 Servomotor
2 Cam cover
3 Adjustable profile cam
4 Cam starting profile adjustment screws
5 Cam end profile adjustment screws
6 Graduated sector for gas butterfly valve
7 Index for graduated sector 6
BLACK LEVER
RED LEVER
ORANGE LEVER
BLUE LEVER
Adjusting air delivery
Progressively adjust the end profile of cam 3)(A)
by turning the screws 5).
- Turn the screws clockwise to increase air
delivery.
- Turn the screws counter-clockwise to reduce
air delivery.
3 - 1ST STAGE OUTPUT
Burner power in 1st stage operation must be
selected within the firing rate range shown on
page 4.
Set the switch 2)(A)p.13 to the 1st stage posi-
tion: the servomotor 1)(A) will close the air gate
valve and, at the same time, closes the gas but-
terfly valve down to 15°, i.e. down to the original
factory setting.
Adjusting gas delivery
Measure the delivery of gas from the gas meter.
- If this value is to be reduced, decrease the
angle of the orange lever (B) slightly by pro-
ceeding a little at a time until the angle is
changed from 15° to 13° or 11°....
- If it is necessary to increase the mains pres-
sure, move to 2nd stage operation by altering
the setting of switch 2)(A)p.13 and increase
the angle of the orange lever, proceeding a lit-
tle at a time until the angle is changed from
15° to 17° - 19°....
(A)
At this point return to 1st stage operation and
measure gas delivery.
Note
The servomotor follows the adjustment of the
orange lever only when the angle is reduced.
If, however the angle must be increased, switch
to 2nd stage operation, increase the angle and
then return to 1st stage operation to check the
effect of the adjustment.
Adjustment of air delivery
Progressively adjust the starting profile of cam
3)(A) by turning the screws 4). It is preferable
not to turn the first screw since this is used to set
the air gate valve to its fully-closed position.
4 - INTERMEDIATE OUTPUTS
Adjustment of gas delivery
No adjustment of gas delivery is required.
Adjustment of air delivery
Switch off the burner using switch 1)(A)p.13 and
turn the central screws of the cam so that the
(B)
cam offers a progressive gradient.
Do not alter the position of the screws at each
end of the cam track, which have already been
adjusted for 1st and 2nd stage air gate valve
control.
Note
Once you have finished adjusting outputs 2ND
STAGE - 1ST STAGE - INTERMEDIATE, check
ignition once again: noise emission at this stage
must be identical to the following stage of opera-
tion.
If you notice any sign of pulsations, reduce the
ignition stage delivery.
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