Fuel Pre-Heating Function (For Burners Equipped With Heater); Shutdown Test; Diagnosis Of The Flame Signal Quality; Intermittent Operation - Riello 484LD2X Installation, Use And Maintenance Instructions

8.8.3 Fuel pre-heating function (for burners
equipped with heater)
If the burner is equipped with the fuel pre-heating function, in the
presence of a start request from the heat request thermostat of
the boiler, the burner awaits the closure of the start-up thermostat
(or pre-heating, K) positioned on the nozzle holder.
If the start-up thermostat (or the pre-heating one) does not close
within 600 seconds, the burner goes into lockout mode.
If the flame goes out during operation, the burner carries out re-
cycling if the contact of the start-up thermostat (or the pre-heating
one, K) is closed.
If the flame goes out during operation and the contact of the start
up thermostat (or the pre-heating one, K) is open, the purging
stops and the burner waiting for the closure of the contact of the
start up thermostat (or the pre-heating one, K) to restart with the
pre-purging time.
8.8.4

Shutdown test

If, during operations, the reset push-button is pressed for longer
than 5 seconds and less than 10 seconds, (so as not to go to the
next menu) the burner switches off, the oil valve closes, the flame
is extinguished and the starting sequence restarts.
If the switch off test is enabled, the number of repetitions of the
start up sequence (see section 8.8.7) and the number of possible
resets (see section 8.8.11), are reset.
8.8.5

Diagnosis of the flame signal quality

The burner allows a light diagnosis of the flame during the burner
run operation.
Flame quality
Acceptable
Good
Excellent
NOTE:
If the detected signal is more than 6 times the minimum threshold
value (approximately 3 lux), the green LED will be constant. Oth-
erwise, the number of blinks will indicate the quantity of signal
coming from the sensor (no. of blinks * approx. 3 lux). The detect-
ed signal depends on the sensitivity of the sensor used, and its
tolerance; if the sensor is highly sensitive, the signal level will be
high (for the same flame).
Flame detection
Type of sensitive element
Functioning principle
Sensitivity to the flame during the
pre-purging
Typical sensitivity to the flame
during normal operation
Typical sensitivity to the flame
failure
NOTE:
With 2 lux, the burner goes into lockout after 3 cycle repeats
8.8.6

Intermittent operation

After (at the most) 24 hours of continuous operation, the control
box starts the automatic switch off sequence, followed by a re-
start, in order to check for a possible fault with the flame sensor.
It is possible to set up this automatic switch off to 1 hour, (see the
section 8.10).
Start-up, calibration and operation of the burner
Number of green LED blinks
1 - 2 blinks
3 - 4 blinks
5 blinks, or always ON
Parameters
Photo-conductive cell
Detection of visible light
> 1 Lux
> 3 Lux
< 2 Lux
8.8.7

Recycle and limit of repetitions

The control box allows a recycle, i.e. complete repetition of the
start-up sequence, making up to 3 attempts, in the event the
flame failure during operation.
If the flame failure 4 times during operations, this will cause a
burner lockout. If there is a new demand for heat during the recy-
cle, the 3 attempts are reset when the limit thermostat (TL)
switches.
NOTE:
After 510 seconds of continuous operation, a new attempt of
possibility is added.
By disconnecting the power supply, when a new heat request oc-
curs (power supply is applied to the burner) all possible attempts
at re-ignition are reset (maximum 3).
8.8.8 Presence of an extraneous light or parasite
flame
If when the fan motor starts, during the pre-purging, an extrane-
ous light or parasite flame is detected the burner remains in purg-
ing until it disappears or the lockout condition is reached 25
seconds.
If the parasite flame or the extraneous light are detected during
the pre-purging, the pre-purging time of 15 seconds is reset and
the time for checking for the presence of a parasite flame or ex-
traneous light begins (the motor continues to purge).
The function is cumulative and can be carried out a maximum of
2 times. If at the 24th second the parasite flame or the extraneous
light disappears, the pre-purging time starts and if the parasite
flame or the extraneous light reappear the pre-purging time is re-
set and the countdown of 25 seconds for checking for the pres-
ence of the parasite flame or the extraneous light restarts.
The third time that the parasite flame or the extraneous light ap-
pears the burner goes into lockout.
If during the recycle due to flame disappearance while operating
and the consequent repetition of the start-up sequence the para-
site flame or the extraneous light is detected, the countdown of
25 seconds starts for checking for the presence of the parasite
flame or the extraneous light.
The presence of the parasite flame or extraneous light is also de-
tected in the "t2" state (the burner does not start). The fault is in-
dicated by way of the blinking LED (see section 8.8.2).
8.8.9

Pre and post spark ignition

In the pre-spark ignition time the ignition device starts 2 seconds
before the oil valve opens.
In the post-spark ignition time, the ignition device stops 3 sec-
onds after safety time.
The spark ignition is present during all safety time.
NOTE:
In case of continuous recycling or heat requests close to
one another, the maximum permissible number of cycle rep-
etitions of the ignition transformer is one attempt every min-
ute.

8.8.10 Reset protection and remote reset

The system will only unlock after the button has been released.
The unit can also be reset via an external button (remote reset)
which connects the L terminal (LINE) to the RESET terminal (re-
fer to the wiring diagrams). Max length of external remote reset
cable is 3 meters.

8.8.11 Reset push-button anomaly

if the reset push-button or the remote reset breaks or is kept
pressed for more than 60 seconds, the fault is indicated by the
blinking of the led (see section 8.8.2) as long as the fault is pres-
23 GB
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