20019893
30
GB
Start-up, calibration and operation of the burner
5.8.5
Minimum burner output
Minimum output must be selected within the “Firing rates” range
shown at page 9.
➤
Move the selector 21)(Fig. 5, page 12) to “MAN” position.
➤
Move the selector 45)(Fig. 5) to position “-”, reduce output,
until the servomotor has closed the air damper and the gas
butterfly valve to 15° (factory set adjustment).
Measure the delivery of gas from the gas meter.
➤
If this value is to be reduced, decrease the position of cam 3),
lower servomotor angle slightly by proceeding a little at a time
until the angle is changed from 15° to 13° or 11°.... set cam 3)
to selected position.
➤
If it has to be increased use “+”, to raise output, increase ser-
vomotor angle with small successive movements, i.e. take it
from angle 15° to 17° 19°....
➤
Use “-” to reduce output until the servomotor is in the minimum
position, measure the gas delivery.
Adjustment of air delivery
Progressively adjust the starting profile of burner cam 4)(Fig. 39)
by turning the screws 5), working throught the access hole.
Key (Fig. 39)
1
Servomotor
2
Gas butterfly valve
3
Gas butterfly valve index
4
Air profile cam
5
Low fire air adjustment screws
6
High fire air adjustment screws
7
Opening for access to screw 5-6
5.8.6
Intermediate outputs
Adjustment of gas delivery
No adjustment of gas delivery is required.
Adjustment of air delivery
➤
Place the selector 21)(Fig. 5, page 12) in “MAN” position.
➤
Place the selector 45)(Fig. 5) in middle position and set the
variable profile burner cam 4)(Fig. 39) by turning the screws
5).
➤
If the burner operation is low-high it is sufficient to set only
minimum and maximum firing rates
➤
If the burner operation is modulating, all the points of modula-
tion should be adjusted.
When the adjustment is complete, release the servomotor and
manually check there is no binding of the cam.
WARNING
The servomotor follows the adjustment of cam only
when the cam angle is reduced.
If it is necessary to increase low fire, first increase
the servomotor angle with "+", set cam 3 to desired
angle, reduce servomotor position with "-".
Fig. 39
1
2
3
4
6
5
7
D10955
