Burner Operation - Riello RL 28/M Installation, Use And Maintenance Instructions

(A)
(B)
D872
D873
12

BURNER OPERATION

BURNER STARTING (A) - (B)
0 s : Control device TL closes, the motor
starts.
The pump 3) sucks the fuel from the
tank through the piping 1) and the filter
2) and pumps it under pressure to deliv-
ery. The piston 4) rises and the fuel re-
turns to the tank through the piping 5) -
7). The screw 6) closes the by-pass
heading towards suction and the de-en-
ergized solenoid valves 8) - 15) - 16)
close the passage to the nozzle.
5 s : Servomotor starts: 90° rotation to right,
until contact is made on cam I)(A)p.9.
The air gate valve is positioned on
MAX. output.
29 s : Pre-purge stage with air delivery at
MAX. output.
51 s : Servomotor rotates to left until contact
is made on cam III)(A)p.9.
71 s : Air gate valve and pressure regulator
are positioned on MIN output.
72,5 s : Ignition electrode strikes a spark.
75 s : Solenoid valves 8) - 15) - 16) open; the
fuel passes through the piping 9) and fil-
ter 10), finally it enters the nozzle.
A part of the fuel is then sprayed out
through the nozzle, igniting when it
comes into contact with the spark: flame
at a low output level, point A; the rest of
the fuel passes through piping 11) at the
pressure adjusted by the regulator 12),
then, through piping 7), it goes back into
the tank.
80 s : The spark goes out.
90 s : The starting cycle ends.
STEADY STATE OPERATION (A)
Burner without output regulator RWF40
At the end of the starting cycle, the servo-motor
control then passes to load control TR for boiler
pressure or temperature, point B.
• If the temperature or pressure is low (and the
TR load control is consequently closed), the
burner progressively increases output up to
MAX (section B-C).
• If subsequently the temperature or pressure
increases until TR opens, the burner progres-
sively decreases output down to MIN (section
D-E). And so on.
• The burner locks out when demand for heat is
less than the heat supplied by the burner in the
MIN output (section F-G).
Load control TL opens. The servomotor re-
turns to the 0° angle limited by contact with
cam II)(A)p.9. The gate valve closes com-
pletely to reduce thermal dispersion to a mini-
mum.
Every time output is changed, the servomotor
automatically modifies gas oil delivery (pressure
regulator) and air delivery (fan gate valve).
Burner with output regulator RWF40
See the handbook enclosed with the regulator.
FIRING FAILURE
If the burner does not fire, it goes into lock-out
within 5 s of the opening of the light oil valve.
FIRING FAILURE
If the flame should go out for accidental reasons
during operation, the burner will lock out in 1 s.