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Idiomas disponibles
Start-up, calibration and operation of the burner
5
5.6
Operation sequence of the burner
Burner start-up
• 0s:
Load control TL closes.
Fan motor starts.
• 6s:
Servomotor starts: 130° rotation to right, until contact
is made on cam I (Fig. 7).
The air gate valve is positioned to MAX. output.
• 36s:
Pre-purge stage with air delivery at MAX. output.
Duration 32 seconds.
• 102s: Servomotor rotates to left up to the angle set on cam I
I I (Fig. 7) for MIN. output.
• 122s: The air gate valve and the gas butterfly are positioned
to MIN. output, with cam I I I (Fig. 7) at 20°.
• 123s: Ignition electrode strikes a spark.
• 128s: Safety valve VS and adjustment valve VR (rapid open-
ing) open. The flame is ignited at a low output level,
point A.
Delivery is then progressively increased, with the
valve VR opening slowly up to MIN. output, point B.
• 130s: The spark goes out.
• 156s: The control box starting cycle ends.
STANDARD IGNITION
M
V 1
V 3
V 2
M
Steady state operation
Burner without the modulating operation kit
Once the start-up cycle is completed, the servomotor command
moves on to the TR that controls the pressure or the tempera-
ture in the boiler, point C.
(The electrical control box still continues to check the presence
of the flame and the correct position of the air and gas maximum
pressure switches).
• If the temperature is low, so the remote control TR is closed,
the burner progressively increases the output up to the MAX
value (tract C-D).
• If subsequently the temperature or pressure increases until
TR opens, the burner progressively decreases its output to the
MIN. value (section E-F). The sequence repeats endlessly.
20032905
• The burner locks out when the heat request is less than the
heat supplied by the burner at MIN. output, (section G-H. The
TL opens, and the servomotor returns to angle 0°. The air
damper closes completely to reduce heat losses to a mini-
mum.
Burner with modulating operation kit
See the handbook enclosed with the adjuster.
Ignition failure
If the burner does not switch on, there is a lockout within 3s of
the electrical supply reaching the gas valve.
It may be that the gas does not arrive at the combustion head
within the safety time of 3s.
In this case increase gas ignition delivery.
M
V1
V3
M
5.7
Burner flame goes out during operation
If the flame should accidentally go out during operation, the
burner will lock out within 1s.
D9762
Fig. 33
5.8
Stopping of the burner
The burner can be stopped by:
intervening on the disconnecting switch of the electrical sup-
ply line, located on the boiler panel;
removing the hood and working on the "AUT/MAN" switch of
Fig. 27.
22
GB
D9763
Fig. 34
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