Pressure Regulator; Min Burner Output; Max Burner Output; Intermediate Outputs Between Max And Min Output - Riello RL 190/M Installation, Use And Maintenance Instructions

7.3.3

Pressure regulator

Using the pressure-output diagram which characterises the re-
turn-type nozzles, see (Fig. 11 and Fig. 12 at page 15), it is pos-
sible to determine 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 modula-
tion output.
– The fuel pressure on the nozzle delivery is adjusted on the
pressure transformer unit and displayed on the pressure
gauge 1)(Fig. 28).
– The fuel pressure on the nozzle return is adjusted on the
pressure transformer unit and displayed on the pressure
gauge 2)(Fig. 28).
– 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. 28); 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
eccentric 6)(Fig. 28) screw 7); screw down said screw to in-
crease the pressure and unscrew to decrease it.
– Adjustment of the air is carried out by means of the screws
3)(Fig. 29 at page 23) of the variable profile cam 2)(Fig. 29),
which control the air damper; screw down said screws to in-
crease the air delivery and unscrew to decrease it.
D1984
Key (Fig. 28)
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
7.3.4

MIN burner output

Min. output must be selected within the firing rate range seen on
page 10.
Press button 2)(Fig. 24) "output reduction" and keep it pressed
until the servomotor has reached 20° (factory setting).
Adjust the pressure of the fuel on the nozzle return, operating
solely by means of the nut 5) (Fig. 28); the desired pressure for
firing and minimum output is set in this manner.
7.3.5

MAX burner output

Max output of the burner must be set within the firing rate range
shown on page 10.
After adjusting the firing and minimum modulation output, pro-
ceed with adjusting the maximum output by pressing the button
Start-up, calibration and operation of the burner
Fig. 28
2)(Fig. 24) towards the "+" sign until the servomotor (Fig. 27)
reaches the maximum position of 130°.
Once maximum opening of the servomotor has been achieved,
adjust the pressure of the fuel on the nozzle return again only by
means of the screw 6)(Fig. 28) of the eccentric; the desired pres-
sure for maximum output is set in this manner.
Screw down the screw 6) only until it corresponds to an increase
in pressure; in this way a variation on the whole rotation angle is
ensured.
At this point lock the nut and the lock nut 5) and the two screws
8) of the pressure transformer unit.
7.3.6 Intermediate outputs between MAX and MIN
output
The setting of the minimum and maximum pressure automatically
determines the pressure values and therefore those of the inter-
mediate outputs.
Combustion setting
During setting of the minimum and maximum pressure it is suffi-
cient to regulate an acceptable excess of combustion air judged
visibly solely.
Only after having set the minimum and maximum pressure, carry
out an accurate setting of the combustion on different positions of
modulation operating solely on the setting of the air delivery by
means of the screws 3)(Fig. 29) of the cam.
Press the switch 2)(Fig. 24) "output increase" a little so that the
servomotor turns by about 15°.
Adjust the screws until optimal combustion is obtained. Proceed
in the same way with the other screws.
Take care that the cam profile variation is progres-
sive.
WARNING
Once the setting of the combustion is complete, lock the screws
4)(Fig. 29) and check ignition once again: noise emission at this
stage must be identical to the following stage of operation.
If you notice any sign of pulsations, reduce the ignition stage de-
livery.
D1229
Key (Fig. 29)
1 Servomotor
2 Adjustable profile cam
3 Adjustment screws for cam profile
4 Adjustment fixing screws
5 Adjustment screws for cam profile
23
GB
Fig. 29
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