1St Stage Burner Output; Intermediate Outputs - Riello RS 34 MZ Installation, Use And Maintenance Instructions

D518
1 Servomotor
2 Cam 4 engaged/
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)
disengages
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).
- Lock the screws to increase air delivery.
- Loose the screws to reduce air delivery.

2 - 1ST STAGE BURNER OUTPUT

Burner power in 1st stage operation must be
selected within the firing rate range shown on
page 5.
Set the switch 2)(A)p.11 to the 1st stage posi-
tion: the servomotor 1)(A) will close the air
damper and, at the same time, closes the gas
butterfly valve down to 15°, i.e. down to the orig-
inal factory setting.
Adjustment of 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 it, move to 2nd
stage operation by altering the setting of
switch 2)(A)p.11 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, lockout 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
4)(A) by turning the screws working through the
access hole 6)(A). It is preferable not to turn the
first screw since this is used to set the air
damper to its fully-closed position.

3 - INTERMEDIATE OUTPUTS

D520
Adjustment of gas delivery
No adjustment of gas delivery is required.
Adjustment of air delivery
Switch off the burner using switch 1)(A)p.11,
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 damper con-
trol.
NOTE
Once you have finished adjusting 2nd stage -
1st stage - intermediate outputs, check firing
once again: noise emission at this stage must
be identical to the following stage of operation. If
you notice any sign of pulsation, reduce the fir-
ing stage delivery.
12