1St Stage Output; Intermediates Outputs - Riello RS 28 Instrucciones De Instalación, Funcionamiento Y Mantenimiento

D518
1 Servomotor
2 Cam 4 engaged /disengages
3 Cam cover
4 Adjustable profile cam
5 Cam profile adjustment screws
6 Opening for access to screws 5
7 Index for graduated sector 8
8 Graduated sector for gas butterfly valve
(A)
(B)
Adjusting air delivery
Progressively adjust the end profile of cam 4)(A)
by turning the cam adjustment screws as they
appear through the access opening 6)(A).
- 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 cam St1 (B) slightly by proceeding 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 cam St1, proceeding a little at a
time until the angle is changed from 15° to
17° - 19°....
At this point return to 1st stage operation and
measure gas delivery.
Note
The servomotor follows the adjustment of cam
St1 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.
If you increase the angle of St1 while the burner
is operating in 1st stage, lock-out will result.
In order to adjust cam St1, remove press-fit
cover 1), as shown in fig.(B), extract the relevant
key 2) from inside, and fit it into the keyway in
cam St1.
Adjustment of air delivery
Progressively adjust the starting profile of cam
D520
4)(A) by turning the screws working throught the
access hole 6)(A). 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,
disengage the variable profile cam, set the ser-
vomotor shaft slot 2)(A) to a vertical position and
turn the central screws of the cam so that the
cam offers a progressive gradient. Try turning
the cam back and forth by hand a few times until
the movement is completely smooth with no
signs of sticking.
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 2nd stage -
1st stage - intermediate outputs, 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 delivery.
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