55
GB
FUNCTIONING CYCLE
Ignition
On closure of the heat request contact, the fan motor and ignition transformer are inserted and total opening of
the air damper is commanded.
On reaching total opening the pre-ventilation (and pre-ignition) time starts during which the flame amplifier test is
performed along with components associated to safety functions. An amplifier fault that corresponds to a flame
present condition or the breakdown of a component that ensures a safety function prevents the start of the ignition
sequence.At the end of the pre-ventilation time the air damper is positioned in the first stage ignition position with
consequent start of the safety time, during which the first stage solenoid valve is inserted.
With flame signal presence, the ignition transformer is kept inserted until the end of the post-ignition time and
however, no longer than 3s after the end of the safety time.
If there is no ignition during the safety time, the appliance is blocked and the voltage is definitively removed to the
first stage solenoid valve and the ignition transformer. Post-ventilation is performed with the damper totally open,
at the end of which the air damper is closed completely.
Functioning
The external regulator, both 2-stage and 3-stage burners or modulating burners, act to satisfy the proportion of
heat requested.
The opening of the request contact determines the closure of the solenoid valve, burner switch off and, if envisio-
ned, execution of the post-ventilation phase with total opening of the air damper.When the fan is switched off the
air damper then closes completely.
CS
Functioning request consents
FAN
Fan motor
IGN
Ignition transformer
V1
First stage valve
V2
Second stage valve
FL
Flame signal
AL Block signal
SA Air damper
tpv Pre-ventilation time
tpracc Pre-ignition timets Safety time
treg Functioning regulator management delay
0
I
II
AL
FL
V2
V1
IGN
FAN
CS
SA
tpv
tpracc
ts
treg
ON
ACCENSIONE / IGNITION / ЗАЖИГАНИЕ / APRINDERE / ENCENDIDO
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Summary of Contents for LMB LO 300 2ST
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