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7.3.3
MAX power
Max output of the burner must be set within the firing rate range
shown on page 11.
In the above instructions we left the burner running in MIN output
operation. Now press button 2)(Fig. 20 at page 22) "+" until ser-
vomotor arrives at 90°.
Adjusting the nozzle flow rate
The nozzle flow rate varies according to the fuel pressure on the
nozzle return.
Diagram (Fig. 25) indicates this relationship for type A3 Bergonzo
nozzles with pump delivery pressure of 20 bar.
NOTE
With a pump delivery pressure of 20 bars, the pressure on the
nozzle return must not exceed 17 bar.
The pressure difference between pump delivery and nozzle re-
turn must be at least 3 bars. With smaller pressure differences,
the pressure on the nozzle return can be unstable.
To fix the maximum nozzle flow rate, vary the final profile on the
upper cam 7)(Fig. 24) via the screws 8).
The nozzle return pressure value is indicated by the pressure
gauge 10).
Key (Fig. 24)
1
Servomotor
2
Cams 4) - 7) engaged
3
Servomotor cams cover
4
Cam for controlling air gate valve
5
Cam 4) adjustable screws
6
Opening for access to screws 5)
7
Cam for controlling pressure regulator
8
Cam 7) adjustable screws
9
Pressure regulator
10 Gauge for pressure on nozzle return
11 Air gate valve
12 Index
Start-up, calibration and operation of the burner
D869
Fig. 24
/ disengaged
D870
Key (Fig. 25)
Horizontal axis: kg/h, nozzle flow rate
Vertical axis:
bar, nozzle return pressure
Adjusting air delivery
Two shutters 1) and 2)(Fig. 26) are provided to adjust the air.
These shutters are factory set to maximum opening.
Firstly adjust shutter 2) which must be closed gradually until opti-
mum combustion is obtained.
If total closure of shutter 2) is not sufficient, also close shutter 1)
(secondly) as follows:
vary the final profile of the lower cam 4)(Fig. 24) via the
screws 5) inside the opening 6).
If the burner is operated at maximum power, the fan air may not
be sufficient even with both shutters 1) and 2) fully open.
In this case, remove shutter 2) and adjust the air using shutter 1)
only as described above.
Cams 7)-4)(Fig. 24):
–
tighten screws 8)-5) to increase air delivery
–
unscrew screws 8)-5) to reduce air delivery
23
GB
Fig. 25
D871
Fig. 26
20033316
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