Operation Sequence Of The Burner; Burner Starting; Steady State Operation; Undesired Shutdown During Operation - Riello 1301 T Installation, Use And Maintenance Instructions

6.11

Operation sequence of the burner

6.11.1 Burner starting

• 0s : Thermostat/pressure switch TL closes.
Fan motor starts.
• 6s : Motor starts. Servomotor starts: 130° rotation to right,
until contact is made on cam 1)
with light oil operation, or cam 4) with gas operation.
• 48s The air gate valve is positioned on MAX. output.
Pre-purge stage with air delivery at MAX. output.
• 80s : Servomotor rotates to left up to the angle set on cam
3).
with light oil operation, or cam 5) with gas operation.
• 109s : The air gate valve and the gas butterfly are positioned
to MIN. output.
• 113 s : Ignition electrode strikes a spark.
• 116s Pilot valve VP1 and VP2 open.
The flame is ignited at a low output level point A
(Fig. 41).
• 119 s :The spark goes out.
• 130s : Safety valve VS and adjustment valve VR (rapid
stroke) open.
Delivery is then progressively increased, with the
valve opening slowly up to MIN output, point B
(Fig. 41).
• 143s : The control box starting cycle ends.
TL
TR
M
VP1
VP2
VS
VR
M
20010305
Start-up, calibration and operation of the burner
NORMAL FIRING

6.11.2 Steady state operation

➤ Burner without output regulator RWF40
At the end of the starting cycle, the servomotor control then pass-
es to the thermostat/pressure switch TR for boiler pressure or
temperature point C (Fig. 41).
(The control box continues, however, to check that the flame is
present and that the air and gas max. pressure switches are in
the correct position).
– If the temperature or pressure is low (and the thermostat/
pressure switch TR is consequently closed), the burner pro-
gressively increases its output to the MAX. value, (section C-
D).
– If subsequently the temperature or pressure increases until
thermostat/pressure switch TR opens, the burner progres-
sively decreases its output to the MIN. value (section E-F).
And so on.
– The burner locks out when demand for heat is less than the
heat supplied by the burner at min. output (section G-H).
Thermostat/pressure switch TL opens. The servomotor re-
turns to the 0° angle limited by contact with cam 2).
The gate valve closes completely to reduce thermal disper-
sion to a minimum.
Every time output is changed, the servomotor automatically mod-
ifies gas delivery (gas butterfly valve), air delivery (fan gate valve)
and air pressure (2 shutters in the combustion head).
➤ Burner with output regulator RWF40
See the handbook enclosed with the regulator.

6.11.3 Undesired shutdown during operation

If the flame should accidentally go out during operation, the burn-
er will lock out within 1s.

6.11.4 Firing failure

If the burner does not fire, it goes into lock-out within (Fig. 42) 3
s of the opening of the gas solenoid valve and 119 s after the
closing of control device TL.
TL
TR
M
VP1
VP2
D9333
VS
VR
Fig. 41
M
34 GB
D9334
Fig. 42