Riello C9541000, Installation, Use And Maintenance Instructions

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Installation
19
2915847
GB
4.11 Burner operation
4.11.1 Burner starting
• Operating closes.
Fan motor starts.
• Servomotor starts:
90° rotation to right, until contact is made on red cam.
The air damper is positioned to MAX. output.
• Pre-purge stage with air delivery at MAX. output.
• After pre-purge stage, servomotor rotates to left up to the angle
set on blu cam for MIN. output.
• The air damper and the gas butterfly are positioned to MIN. out-
put.
• Ignition electrode strikes a spark.
• Pilot valve opens. The pilot flame is ignited.
• After about 12s the main flame ignites and starting cycle ends.
4.11.2 Steady state operation
Burner without modulating control RWF
At the end of the starting cycle, the servomotor control then passes
to the load control for boiler pressure or temperature.
(The flame safeguard continues, however, to check that the flame
is present and that the air pressure switch is in the correct position.)
•
If the temperature or pressure is low, the burner progressively
increases its output to the MAX. value.
• If the temperature or pressure is high, the burner progressively
decreases its output to the MIN. value. And so on.
• The burner locks out when demand for heat is less than the
heat supplied by the burner at min. output. Load control opens.
The servomotor returns to the 0° angle limited by contact with
orange cam. The air damper closes completely to reduce ther-
mal dispersion to a minimum.
Every time output is changed, the servomotor automatically modi-
fies gas delivery (gas butterfly valve) and air delivery (fan damper).
Burner with modulating control RWF
See the handbook enclosed with the modulating control.
Switching times are given in seconds, in the burner start-up se-
quence.
Tab. K
*
Variable to air damper setting.
Key for the times
t1
Pre-purge time with air damper open
t2 Safety time
t3 Pre-ignition time, short (ignition transformer on terminal 16)
t4 Interval between start of t2 and release of valve at terminal
19
t5 Interval between end of t4 and release of load controller or
valve at terminal 20
t5 Running time of air damper into OPEN position
t6 Running time of air damper into low-flame position (MIN)
t7 Permissible after-burn time
t8 Interval until OPEN command for the air damper is given
t9 Running time of pilot
t10 Interval between end of t4 and end start up sequence
4.11.3 Firing failure
If the burner does not fire, it locks out within 2.5 seconds from
opening the pilot valve and then within 5 seconds from opening
the main valves.
4.11.4 Burner flame goes out during operation
If the flame should accidentally go out during operation, the burner
will lock out within 1s.
LFL 1.335 Series 01
t1
t2
t3
t4
t5 30s
2s
4s
12.5s
*
t6
t7
t8
t9
t10
*
12s
4s
16s
10s
Fig. 19
D7780 FULL MODULATION
t 4 t 10
Fig. 20
D7781
t 4 t 1 0
LOW - HIGH