Riello RDB4 Installation, Use And Maintenance Instructions page 50

7.5.3 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) positioned on the nozzle holder.
If the start-up thermostat does not close within 600 seconds, the
burner goes into lockout mode.
If the flame goes out during operation, the burner performs recy-
cling if the start-up thermostat is closed.
If the flame goes out during operation, the purging stops and the
burner waits for the start-up thermostat to be closed before re-
starting the pre-purging.
7.5.4 Shut-down test
If the reset button or remote reset is pressed during operation, for
more than 5 seconds but less than 10 seconds (to avoid passing
to the next menu), the burner will switch off, the oil valve will
close, the flame will go out, and the start-up sequence will begin
again.
If shut-down test is enabled, the number of repetitions of the start-
up sequence and the number of the reset are restored.
7.5.5 Diagnosis of the flame signal quantity
The burner allows the diagnosis of the quality of the signal arriv-
ing from the flame sensor during operation.
Quality of the flame sensor
signal
Acceptable
Good
Very good
NOTE:
If the signal measured is more than 6 times the minimum thresh-
old value (approx. 3 lux), the green LED will remain ON. Other-
wise, the number of blinks indicates the quality of the signal
arriving from the sensor (no. of blinks * approx. 3 lux). The signal
measured 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 lock-out after 3 re-cycles
20071933
Electrical system
Number of green LED blinks
1 - 2 blinks
3 - 4 blinks
5 blinks, or always ON
Parameters
Photoconductive cell
cadmium sulphide
Detection of visible light
> 1 Lux
> 3 Lux
< 2 Lux
7.5.6 Intermittent operation
The control box will initiate automatic reset shutdown followed by
a restart after 24 hours of operation.
It is possible to reduce this automatic shutdown to 1 hour (see
programming menu paragraph) to check for a possible failure of
the flame detector, see "Notes on safety for the electrical wir-
ing" on page 17.
7.5.7 Recycle and limit of repetitions
The control box has a recycle function - i.e. the complete repeti-
tion of the start-up sequence - with which up to 3 attempts are
made if the flame goes out during operation.
If the flame fails 4 times during operations, this will cause the
burner to lock out. If there is a new heat request during the recy-
cle, then the 3 attempts are reset with the switching of the heat
request thermostat.
NOTE:
After 510 seconds of continuous operation a new attempt of
possibility is added.
By disconnecting power supply, when new heat demand occur
(power supply is applied to the burner) all attempts re-ignition
possibilities are allowed (3 maximum).
7.5.8 Extraneous light present or parasite flame
If, at the moment that the boiler heat request thermostat com-
mands the burner to start, an extraneous light or a parasitic flame
is detected, the burner will remain idle until the light or flame dis-
appears. Otherwise the system will lock after 25 seconds.
If the extraneous light or the parasitic flame is detected during
pre-purging, the burner locks immediately.
The fault is indicated by way of the blinking LED (See "Faults di-
agnosis - lockouts" on page 19.).
7.5.9 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 ignition is present throughout the safety time.
NOTE:
In the case of continuous recycle or another heat request in
a short time, the repetitions of the ignition transformer func-
in
tion cycle may not exceed one attempt per minute.
7.5.10 Reset protection and remote reset
The burner can be reset by pushing the built-in reset button for
more than 1s (< 2s).
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.
NOTE:
The burner can only be reset 5 consecutive times; after this,
you must disconnect the power supply to obtain a further 5
reset attempts.
The burner can only be reset if power supply is applied to the
control box.
20 GB