Riello RL 70/M - Operation Sequence of the Burner; Final Checks

20166443
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Start-up, calibration and operation of the burner
7.5 Operation sequence of the burner
7.5.1 Burner starting
7.5.2 Steady state operation (Fig. 34)
Burner without output regulator RWF
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 con-
trol 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 progressively 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 returns to the 0°
angle limited by contact with cam II)(Fig. 31 on page 26).
The gate valve closes completely to reduce thermal disper-
sion to a minimum.
Every time output is changed, the servomotor automatically mod-
ifies gas oil delivery (pressure regulator) and air delivery (fan gate
valve).
Burner with output regulator RWF
See the handbook enclosed with the regulator.
7.5.3 Firing failure
If the burner does not fire, it goes into lock-out within 2.5 s of the
opening of the light oil valve and the pre-purging phase starts and
lasts 15 seconds.
7.5.4 Undesired shut-down during operation
If the flame should go out for accidental reasons during operation,
the burner will lock out in 1 s.
7.6 Final checks
 Obscure the flame sensor and switch off the control
devices: the burner should start and then lock-out about 5 s
after starting.
 Illuminate the flame sensor and switch off the control
devices: burner should go into lock-out.
 Obscure the flame sensor while the burner is operating:
flame should go out and burner lock out within 1 s.
 Switch off control device TL followed by control device
TS while the burner is operating: the burner should stop.
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 pres-
sure to delivery. The piston 4) rises and the fuel
returns to the tank through the piping 5) - 7). The
screw 6) closes the by-pass heading towards suction
and the de-energized solenoid valves 8) - 9) - 16) -
17) close the passage to the nozzle.
6 s : Servomotor starts: 130° rotation to right, until contact
is made on cam I)(Fig. 31 on page 26).The air gate
valve is positioned on MAX. output.
48 s : Pre-purge stage with air delivery at MAX. output.
85 s : Servomotor rotates to left until contact is made on
cam III) (Fig. 31 on page 26).
121 s : Air gate valve and pressure regulator are positioned
on MIN output.
123 s : Ignition electrode strikes a spark.
128 s : Solenoid valves 8) - 9) - 16) open; the fuel passes
through the piping 10) and filter 11), and 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 12 at the pressure
adjusted by the regulator 13, then, through piping 7),
it goes back into the tank.
131 s : The spark goes out.
153 s : The starting cycle ends.
WARNING
Make sure that the mechanical locking systems
on the various adjustment devices are fully
tightened.
0 sec
131
153128
A B
C D
E F
G
6
48 85
121
128
131 123
M
VS VF VR
M
MAX
MIN
0
2
1
0
Fig. 34
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