Servomotor Adjustment; Air/Fuel Adjustment - Riello DB 12 SM C03 TC FS1 FB A0 Installation, Use And Maintenance Instructions

6.4

Servomotor adjustment

The servomotor (Fig. 25) simultaneously adjusts, through driving
gears, the output and pressure of the air, and the flow rate of the
fuel being used.
It is equipped with adjustable cams which operate as many
switches.
Cam 1 : limits the maximum opening of the servomotor.
Cam 2 : limits the servomotor limit switch at the 0° posi-
tion. With the burner off, the air damper is com-
pletely closed.
Cam 3 : establishes the minimum modulation position.
This factory set at 20° (only one fuel).
Cam 4 : limits the maximum opening of the servomotor
(for mixed burners operating with gas).
Cam 5 : limits the minimum output. This factory set at 20°
(for mixed burners operating with gas).
Other cams : available.
For the maximum limit switch (cam 1 - 4) never ex-
ceed 130°.
WARNING
6.5

Air/fuel adjustment

When setting the air/fuel ratio for the gas burners, the air and gas
variable profile cams must be used, Fig. 26.
The gas is adjusted by varying the relative cam profile; to adjust
ignition delivery, it could be useful to turn disc B)(Fig. 27) after
loosening the screw A).
Start-up, calibration and operation of the burner
Key (Fig. 25)
1-4 Limit switch cam (max opening damper)
2 Limit switch cam (closing damper)
3-5 Minimum output position cam (and ignition)
6 Index for reading positioning
7 Servomotor release
1
Key (Fig. 26)
1 Cam
2 Adjustment screws
3 Locking screws
4 Adjustable profile
D1517
25 GB
4 2
D1499
D1500
Fig. 25
3
Fig. 26
Fig. 27
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