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6.8
Air/fuel adjustment
When setting the air/fuel ratio for oil burners, the following adjust-
ments must be made:
A
Delivery pressure of the oil pump:
turn the screw 5) (Fig. 22), on the pump.
B
Air cam:
turn the threaded regulators 2) (Fig. 35) after loosening the
screws 3) (Fig. 35).
C
Gas cam:
adjust set screws 2) (Fig. 35) after loosening the screws 3)
(Fig. 35).
D
Oil cam:
change eccentricity by turning the screw 4) (Fig. 36) after
loosening the screws 7) (Fig. 36).
By tightening the screw 4) (Fig. 36) eccentricity increases, in
this way the difference increases between maximum and
minimum return pressure to the nozzle.
D8369
Key to layout (Fig. 36)
1
Maximum oil pressure switch
2
Manometer for pressure in delivery line
3
Manometer for pressure in return line
4
Eccentric adjusting screw
5
Ring for piston stop
6
Nut and lock-nut for piston setting
7
Eccentric locking screws
8
Variable eccentric
Start-up, calibration and operation of the burner
Fig. 36
Procedures for setting the burner
➤ Fit the suitable nozzle to obtain the maximum required deliv-
ery.
➤ Check that the eccentricity of the oil cam is sufficient for a
run of approx. 8 mm for the oil modulator shaft.
Normally, with an 8 mm run for the shaft, the pressure varia-
tion required for modulating the output from minimum to
maximum is obtained.
To carry out this control, manually turn the cam after releas-
ing the servomotor using the lever 7)(Fig. 37), so that the
shaft run is not excessive or insufficient. When the control is
terminated, remember to block the servomotor.
➤ Ignite the burner with the selector switch on the control panel
in the manual position 1)(Fig. 33).
At this point, after the pre-ventilation phase, the servomotor
will stop at approx. 20°.
➤ Adjust the pump delivery pressure as given in point A (deliv-
ery pressure of the oil pump), to obtain a delivery pressure
of 24 - 25 bar.
➤ Adjust the return pressure to a minimum of approx. 6 bar.
To do this, the length of the shaft 5)(Fig. 36) must be
adjusted, by turning the nut 6)(Fig. 36).
➤ Proceed with setting the air delivery by adjusting the variable
profile cam, by turning the screws 2)(Fig. 35).
➤ After this first adjustment, increase supply output using the
automatic return selection switch on the control panel. Stop
when the servomotor has turned by 15° and then effect a
new adjustment using the variable profile air cam.
We recommend sufficient setting so as not to create a
smoky flame and to reach maximum output as soon as pos-
sible (maximum run for the servomotor 130°): set the return
pressure on the eccentric (screw 4, Fig. 36) to obtain the
output required by the nozzle and then continue with setting
the intermediate levels.
➤ Check the levels of the combustion parameters at the vari-
ous modulation outputs and adjust if necessary.
➤ Move selector 3)(Fig. 33) to GAS and check the correct
operation on gas at the desired power.
If operation was not correct, calibrate gas cam according to
the above mentioned point C (Gas cam).
➤ When perfect adjustment has been reached, remember to
block the adjustment screws of the cam profiles by tighten-
ing the screws 3)(Fig. 35).
When setting the cams, do not exceed the servo-
motor run limits 0° ÷ 130°, to avoid crawling.
Check, by effecting a manual movement of the
WARNING
cam of 0-130°, that there are no mechanical
blocks before the micro-switches 1-2 on the ser-
vomotor trigger.
31
GB
20010305
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