21
20024198
GB
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 re-
quire modification under normal circumstances:
Combustion head
Servomotor, cams I - II - IV - V
Contrarily, the settings listed below must be adjusted in se-
quence:
1
MIN burner output;
2
MAX burner output;
3
Intermediate outputs between MAX and MIN output.
Using the pressure-output diagram which characterises the re-
turn-type nozzles, see (Fig. 25) and (Fig. 26), it is possible to de-
termine the size of the nozzle to use in relation to the maximum
fuel output to be burnt and consequently establish the minimum
and maximum pressure of the fuel on the nozzle return in relation
to the corresponding minimum and maximum modulation output.
The fuel pressure on the nozzle delivery is adjusted on the pres-
sure transformer unit and displayed on the pressure gauge
1)(Fig. 24).
The fuel pressure on the nozzle return is adjusted on the pres-
sure transformer unit and displayed on the pressure gauge
2)(Fig. 24).
The adjustment of the MINIMUM pressure of the fuel on the
nozzle return must be carried out solely by means of the nut
5) (Fig. 24);
screw down said nut to decrease the pressure and
unscrew to increase it.
The adjustment of the MAXIMUM pressure of the fuel on the
nozzle return must be carried out solely by means of the ec-
centric 6) (Fig. 24) screw 7) (Fig. 24);
screw down said screw
to increase the pressure and unscrew to decrease it.
Adjustment of the air is carried out by means of the screws 3) of
the variable profile cam 2)(Fig. 27 page 22) which control the air
damper; screw down said screws to increase the air delivery and
unscrew to decrease it.
Pressure regulator
1
Pressure gauge for pressure on nozzle delivery
2
Pressure gauge for pressure on nozzle return
3
Oil pressure switch
4
Ring for piston stop
5
Nut and lock-nut for piston setting
6
Eccentric adjusting screw
7
Variable eccentric
8
Eccentric locking screws
8
Burner calibration
Fig. 24
D1984
Fig. 25
D1982
Return pressure bar
Nozzle f
low rate
kg/h
Type A3 Bergonzo nozzles (45°)
Deliv
e
ry
p
res
sur
e
20 ba
r
Fig. 26
Return pressure bar
Nozzle flo
w
rate
kg
/h
Type A4 Bergonzo nozzles (45°)
Deliv
e
ry
p
res
sur
e
20 ba
r
D1983
