Preliminary Calibrations, If Necessary - Riello GAS 8 P/M Installation, Use And Maintenance Instructions

6.6.2

Preliminary calibrations, if necessary

7)(Fig. 6 on page 12)
D74
They concern the disc (Fig. 29) of the gas butterfly valve, the tie-
rod (Fig. 28) controlling the disc (Fig. 29) and the tie-rod
7)(Fig. 30) controlling the air damper.
Their calibration depends on the MIN and MAX outputs required
for the burner operation.
• The burner is factory set for a MIN-MAX output ratio of 1:3 -
1:4. The articulated coupling 1)(Fig. 28) controlling the disc
(Fig. 29) of the gas butterfly valve is positioned at 90°.
In this way the gas butterfly valve turns by 90° when the cam
2)(Fig. 30) covers the whole angle of 130° (A) (Fig. 31).
S10123
20148758
Start-up, calibration and operation of the burner
Fig. 28
S9526
When the MIN-MAX ratio is approximately 1:2, the articulated
coupling 1)(Fig. 28) must be moved from 90° hole to 60° hole
(Fig. 29), with the burner off.
In this case the gas butterfly valve turns by 60° when the cam
2)(Fig. 30) covers the whole angle of 130° (B) (Fig. 31).
On the disc (Fig. 29) there are two additional holes, 75° and
45°, that can be used in special cases, when the working an-
gle of the butterfly valve is to be reduced in the presence of a
higher gas pressure upstream of the butterfly valve itself.
30 GB
Fig. 29
D75
Fig. 30
Fig. 31