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6.3
Servomotor adjustment
The servomotor provides simultaneous adjustment of the air
damper, by means of the variable profile cam and the gas
butterfly valve. The servomotor rotates by 130° in 42 s.
Do not alter the factory setting for the 5 cams;
just check that they are as specified below:
ATTENTION
130° . Limits rotation toward maximum
position. When the burner is operating at
Cam I:
MAX output, the gas butterfly valve must be
fully open: 90°.
0° . Limits rotation toward minimum position.
When the burner is shut down, the air
Cam II:
damper and gas butterfly valve must be
closed: 0°.
30° . Adjusts the ignition position and the MIN
Cam III:
output.
Cams IV and V:
Not used.
6.4
Burner start-up
Feed electricity to the burner via the disconnecting switch on the
boiler panel.
Close the thermostats/pressure switches and turn the switch in
Fig. 31 to position " MAN ".
6.5
Burner ignition
If the motor starts up, but the flame does not appear and the
control box goes into lockout, reset it and wait for a new
ignition attempt.
If ignition is still not achieved, it may be that gas is not
reaching the combustion head within the safety time period of
3 seconds. In this case, increase gas ignition delivery.
The arrival of gas to the sleeve is indicated by the U-type
pressure gauge (Fig. 29 on page 29).
Once ignition has taken place, proceed with burner global
calibration operations.
20152093
Start-up, calibration and operation of the burner
D887
Check that the lamps or the testers connected to the
solenoid valves or the pilot lights on the solenoid
valves indicate that no voltage is present.
DANGER
If they indicate the presence of voltage, stop the
burner immediately and check the electric
connections.
As soon as burner starts, check the fan rotation direction
through the flame inspection window.
30
GB
Fig. 30
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