20045163
26
GB
Start-up, calibration and operation of the burner
5.1
Notes on safety for the first start-up
5.2
Burner calibration
The optimum calibration of the burner requires an analysis of the
flue gases at the boiler outlet.
The following settings that have already been made do not require
modification under normal circumstances:
– combustion head;
– servomotor
5.3
Adjusting the nozzle flow rate
The nozzle flow rate varies according to the fuel pressure on the
nozzle return.
Diagram (Fig. 33) indicates this relationship for type A4 return flow
nozzles with pump delivery pressure of 290 PSI.
Diagrams (Fig. 33):
Horizontal axis
: PSI, nozzle return pressure
Vertical axis
: GPH, nozzle flow rate
The values indicated in the right side of the diagram, refer to the
data printed on the nozzle.
NOTE:
with a pump delivery pressure of 290 PSI, the pressure on the
nozzle return must not exceed 246.5 PSI.
The pressure difference between pump delivery and nozzle return
must be at least 43.5 PSI. With smaller pressure differences, the
pressure on the nozzle return can be unstable.
5.3.1
Pressure controller
1 - Gauge for pressure in return line
2 - Oil pressure switch
3 - Ring for piston stop
4 - Nut and lock-nut for piston setting
5 - Eccentric adjusting screw
6 - Variable eccentric
7 - Eccentric locking screws
The nozzle return pressure value is indicated by the pressure
gauge 1)(Fig. 34).
The output and the pressure of the nozzle are at maximum when
the servomotor is positioned on maximum.
The fine adjustment of the pressure in the return line may be car-
ried out by changing the setting of the eccentric 6)(Fig. 34), of the
nut and lock-nut 4)(Fig. 34).
5
Start-up, calibration and operation of the burner
WARNING
The first start-up of the burner must be carried out
by qualified personnel, as indicated in this manual
and in compliance with the standards and regula-
tions of the laws in force.
WARNING
Check the correct working of the adjustment, com-
mand and safety devices.
Type A4 return flow nozzle (45°)
D2355
N
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Return pressure
Delivery pressure 290 PSI
Fig. 33
D1227
Fig. 34
