Burner Calibration - Riello RL 70/M Installation, Use And Maintenance Instructions

PRESSURE CONTROLLER
D1227
(A)
Type A4 return flow nozzle (45°)
The values indicated in the right side of the diagram, refer to the data printed
on the nozzle.
(B)
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
Delivery pressure 290 PSI
Return pressure

BURNER CALIBRATION

The optimum calibration of the burner requires an analy-
sis 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, cams I - II - III
ADJUSTING THE NOZZLE FLOW RATE
The nozzle flow rate varies according to the fuel pres-
sure on the nozzle return.
Diagram (B) indicates this relationship for type A4 return
flow nozzles with pump delivery pressure of 290 PSI.
Diagrams (B):
Horizontal axis
Vertical axis
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.
The nozzle return pressure value is indicated by the
pressure gauge 1)(A).
The output and the pressure of the nozzle are at maxi-
mum when the servomotor is positioned on maximum.
The fine adjustment of the pressure in the return line
may be carried out by changing the setting of the eccen-
tric 6)(A), of the nut and lock-nut 4)(A).
The eccentric setting should be carried out by loosening
screws 7), and turning the screw 5) to obtain the desired
eccentricity. Turn clockwise, screw 5) to increase the
eccentricity, increasing the difference between the min.
and max. capacity of the nozzle; turn counter-clockwise,
screw 5) to decrease the eccentricity and, consequently
the difference between the min. and max. capacity of the
nozzle.
NOTE
• The proper setting of the eccentric 6) is possible when
its operation field follows the servomotor operation
field (20° ÷ 130°): so, that every variation of the servo-
motor position corresponds to a pressure variation.
• Do not let the piston bottom out repeatedly: the
stop ring 3)(A) determines the max. stroke.
• When the setting is carried out, verify manually that no
slow-down occurs between 0° and 130° and that the
maximum and minimum pressures correspond to
those chosen as per diagrams (B).
• If you wish to check the delivery capacity of the nozzle,
open the burner, attach the nozzle, simulate the start-
up and then proceed with observing of the maximum
and minimum pressures of the fuel.
• If at the maximum capacity of the nozzle (maximum
pressure in the return line) pressure fluctuations are
detected on the gauge 1), slightly decrease the pres-
sure in the return line until they are completely elimi-
nated.
D2355
11
: PSI, nozzle return pressure
: GPH, nozzle flow rate