29
20135737
GB
Installation
5.13.19 Checking the faults of the 1st and 2nd stage
valve and the motor
The control box detects the presence of a fault in the controls of
the valves and the motor, the fault is indicated by the blinking
LED (see paragraph
“Fault diagnostics - lockouts”
page 26):
if the anomaly is detected during the initialisation, the burner
goes into lockout.
if the anomaly is detected during the pre-purging, the burner
goes into lockout.
During a recycling, if the fault is detected, the burner does
not start and goes into lockout.
The fault is not detected if the burner is in lockout.
The sealing of the contact of the relay inside the motor's control
box is intercepted if the gas pressure switch is closed and the
motor is connected to the board.
The sealing of the contact of the relay inside the 1st stage valve
control is intercepted only with the motor running.
The sealing of the contact of the relay inside the 2nd stage valve
control can only be intercepted when the motor is on and the 1st
stage valve is controlled.
5.13.20 EEprom check
The control box automatically detects if EEprom memory of mi-
cro-controller has failed and will perform a lockout. The lockout is
indicated by the blinking of the LED (see paragraph
5.13.21 Ionisation current
The recommended minimum for operating the burner is 5 µA.
The burner normally supplies a higher current value, so that no
check is needed.
In any event, if you want to measure the ionisation current, you
need to open the connector (CN1)(Fig. 22) on the red wire and
insert a microammeter.
5.13.22 Post-purging
Post-purging is a function that allows you to maintain the air purg-
ing even after the burner is switched off in the absence of the heat
request for a pre-set time. The burner switches off the flame
when the heat request thermostat opens, cutting off the fuel sup-
ply to the valves.
The post-purging function is not performed:
after a lockout of the motor or valves;
if the heat request is interrupted during pre-purging.
Post-purging occurs:
if the heat request is interrupted during the safety time;
if the heat request is interrupted during normal operation;
with all types of lockout.
NOTE:
If during post-purging there is an extraneous light or a parasite
flame the burner goes into lockout after 25 seconds and post-
purging is not stopped.
If during post-purging there is a new heat request, the post-purg-
ing time is halted, the fan motor stops and a new burner operating
cycle starts.
5.13.23 Continuous purging
Continuous purging is a function that maintains the air ventilation
independently of the request for burner ignition.
From the moment when it is set, the motor remains in operation
both when the limit thermostat (TL) is not switched over (burner
switched off), and when the burner is in lockout.
With the commutation of the limit thermostat (TL) the motor stops
for the standby time of 2 seconds, the successive control of the
air pressure switch and the start of a new burner operation cycle.
If during continuous purging when there is no heat request a
parasite flame is detected, the motor stays on and a fault is
signalled. The burner reaches the lockout condition after 25
seconds.
If during continuous purging a parasite flame is detected, the
motor stays on but if a heat request occurs the motor is
switched off, the motor is not started after the standby (2sec)
if the parasite flame persists; the burner reaches the lockout
condition after 25 seconds. After the lockout has been reset
the motor is restarted.
The motor stays on even in a lockout.
The continuous purging is interrupted if an internal fault is
detected that brings the burner to the lockout condition
(eeprom, motor, 1st and 2nd stage valves).
D4631
+
_
SO
CN1
Fig. 22
