Adjusting The Nozzle Flow Rate - Riello RL 190/M Installation, Use And Maintenance Instructions

Make sure that the electrodes are positioned as shown in Fig. 15.
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Finally remount the burner 3)(Fig. 16) on the slide bars 2) and slide
it up to the flange 5), keeping it slightly raised to prevent the flame
stability disk from pressing against the blast tube.
Tighten the screws 1) on the slide bars 2) and screws 4) fixing the
burner to the flange.
If it proves necessary to change a nozzle with the burner already
fitted to the boiler, proceed as outlined below:
➤ Pull back the burner on its slide bars as shown in Fig. 17;
➤ Remove the nuts 1) and the disk 2);
➤ Use wrench 3) to change the nozzles.
➤ Do not use any sealing products such as gas-
kets, sealing compound, or tape.
➤ Be careful to avoid damaging the nozzle seal-
ing seat.
WARNING
➤ The nozzles must be screwed into place tightly
but carefully.
➤ The nozzle for low fire operation is the one
lying beneath the firing electrodes (Fig. 17).
➤ Make sure that the electrodes are positioned
as shown in Fig. 17.
2
1
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Installation
Fig. 15
3
4
5
Fig. 16
Fig. 17
18
4.9.3

Adjusting the nozzle flow rate

The nozzle flow rate varies according to the fuel pressure on the
nozzle return.
Diagram (Fig. 19) indicates this relationship for type A4 return flow
nozzles with pump delivery pressure of 290 PSI. See Fig. 19:
Horizontal axis: PSI, nozzle return pressure
Vertical axis: GPH, nozzle flow rate
With a pump delivery pressure of 290 PSI, the pressure on the noz-
zle 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.
The nozzle return pressure value is indicated by the pressure
gauge 1)(Fig. 18).
The nozzle return pressure value is indicated by the pressure
gauge 2)(Fig. 18).
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 7)(Fig. 18), of the
nut and lock-nut 5)(Fig. 18).
The eccentric setting should be carried out by loosening screws 8),
and turning the screw 6) to obtain the desired eccentricity. Turn
clockwise the screw 6) to increase the eccentricity, increasing the
difference between the min. and max. capacity of the nozzle; turn
counter-clockwise the screw 6) to decrease the eccentricity and,
consequently the difference between the min. and max. capacity of
the nozzle.
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1 Gauge for pressure in return line
2 Gauge for pressure in delivery line
3 High oil pressure switch
4 Ring for piston stop
5 Nut and lock-nut for piston setting
6 Variable eccentric
7 Eccentric locking screws
8 Screws
GB
Fig. 18