Riello GI/EMME 1400, Manual

Page: 38 / 80

20162463 36 GB
Start-up, calibration and operation of the burner
6.12 Burner operation
6.12.1 Burner start-up
(gas trains in compliance with EN 676)
6.12.2 Steady state operation
STEADY STATE OPERATION
Burner without RWF50 output regulator
At the end of the start-up cycle, the servomotor control switches
to TR remote control that controls the pressure or temperature in
the boiler, point C. (The electric control box RFGO carries on
checking the presence of the flame and the correct position of the
air and gas maximum pressure switches).
•
If the temperature or pressure is low (so the TR remote
control is closed), the burner progressively increases the
output up to the MAX value (section C-D).
• Then if the temperature or pressure increases until the TR
opens, the burner progressively decreases its output to the
MIN value (section E-F). And so on.
• 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 remote control opens, the servomotor returns to angle 0°
limited by the contact of the cam I)(Fig. 31 on page 30). The
air damper closes completely to reduce heat losses to a
minimum.
Upon every output change, the servomotor will automatically
change the gas flow rate (butterfly valve), the airflow (fan
damper) and the air pressure (2 shutters in the combustion
head).
Burner with output regulator RWF50
See the manual supplied with the regulator.
Burner flame goes out during operation
If the flame should accidentally go out during operation, the
burner will lock out within 1s.
6.12.3 Ignition failure
If the burner does not ignite, it locks out within 3 seconds after the
gas valve opens, 115 seconds after the TL closes and the post-
purging phase starts lasting 12 seconds.
0s : Control remote control TL closes.
Fan servomotor start-up.
6s : Servomotor start-up: turn to the right by 130°, i.e. until
the contact intervenes on cam I (Fig. 31 on page 30).
The air damper is positioned to MAX output.
43s : Pre-purging stage with MAX output air delivery.
Duration 31 seconds.
74s : The servomotor rotates to the left until reaching the angle
set on cam III at 20° (Fig. 31 on page 30), ranging from
10° and 30°.
106s : The air damper and gas butterfly valve assume the MIN
output position (with cam III at 20°)(Fig. 31 on page 30).
109s : Ignition electrode strikes a spark.
113s : The safety valve VS opens, along with the adjustment
valve VR, (quick opening). The flame is ignited at a low
output level, point A.
The output is then progressively increased, with the
valve opening slowly up to MIN output, point B.
115s : The spark goes out.
134s : The start-up cycle ends
Fig. 40
STANDARD IGNITION
(no. = seconds from instant 0)
20162601
Fig. 41
IGNITION FAILURE
20162602