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3
CHARACTERISTICS
3. 1
ELECTRONIC BOARD
The electronic boards are manufactured in
compliance with the EEC 73/23 low-voltage
directives.
They are supplied with 230V and, through a
built-in transformer, send a voltage of 24V
to the following components: gas valve, safe-
ty stat, C.H. and D.H.W. sensor, external
temperature sensor (optional), modulator,
micro divertor valve, flow switch safety
valve, water pressure transducer, room
stat or "Logica Remote Control".
An automatic and continuous modulation
system enables the boiler to adjust the heat
output to the various system requirements
or the User's needs. The electronic compo-
nents are guaranteed against a tempera-
ture range of 0 to +60°C.
3. 1 . 1
Central heating operation
Upon demand for heating from the room
temperature stat or climatic controller
"Logica Remote Control", the circulation
pump is activated, and approximately 90
seconds must elapse for the burner to
start operating. This will happen only if the
temperature is set above the value detect-
ed by the heating sensor. The heat output
can be varied according to the system
needs by adjusting the trimmer (14 fig. 16).
At start-up of each working cycle, after the
period of slow ignition having a duration of
approx. 3 sec, the boiler will set itself at the
heat output set on the trimmer.
Flashing red led, fan fault. 30 minutes
after the fan has switched off,
the board will attempt a restart
Red led on, ignition blocked:
rotate selector
CR/OFF/EST/INV/RESET
to release position ( )
to restore operation
Green led off if
power is cut-off
Flashing red led, safety thermostat
tripped. Rotate selector
CR/OFF/EST/INV/RESET
to release position ( ) to
restore operation
3. 1 .2
D.H.W. operation
Upon demand for hot water, the boiler
starts
instantaneously
when
microswitch on the divertor valve makes.
The required power output is regulated,
via flame modulation, by the D.H.W. sensor
(with fixed limit 67°C), which will compare
the temperature read with the tempera-
ture set on the potentiometer.
With the delivery temperature between
70÷75°C, the flame modulation is effected
by the heating sensor. When the heating
flow sensor is at 75°C the electronic limiter
will trip and switch-off the burner.
3. 1 .3
Fault finding
The indicator leds signalling irregular
and/or incorrect operation of the equip-
ment are indicated in fig. 15.
3. 1 .4
Devices
The electronic board is equipped with the
following devices:
– "POT. RISC." trimmer (14 fig. 16)
Sets the maximum heating power value.
To increase the value turn the trimmer
clockwise; to reduce the value turn the
trimmer anticlockwise.
– "POT. ACC." trimmer (8 fig. 16)
Trimmer to vary the pressure level upon
Flashing red led,
communication fault
with "Logica Remote
Control"
Flashing red led, domestic hot water sensor fault (SS)
ignition (STEP), of the gas valve.
According to the type of gas for which the
boiler is equipped, the trimmer must be
the
regulated so as to obtain a pressure of
approx. 3 mbar at the burner for
methane gas and 7 mbar for butane gas
(G30) and propane gas (G31).
To increase pressure, turn the trimmer
clockwise; to reduce pressure, turn the
trimmer counterclockwise.
The slow ignition pressure level can be
set during the first 3 seconds following
burner ignition.
After setting the pressure level upon
ignition (STEP) according to the type of
gas, check that the pressure for heat-
ing is still at the value previously set.
– "MET-GPL" connector (11 fig. 16)
With the connector switched-off, the boil-
er is set-up for natural gas; with the con-
nector switched-on, the boiler is ready for
LPG.
– "ANN. RIT." connector (7 fig. 16):
In the heating phase, the electronic
board is programmed to include a burner
technical delay interval of approx. 90 sec-
onds, which occurs both at system cold
starting and at subsequent re-ignitions.
The aim is to overcome the problem of
repeated ignitions and turning off with
very short time intervals between. This
could occur in particular in systems pre-
senting high head losses. At each restart
after the period of slow ignition, the boil-
er will set itself for about 1 minute at the
(*) When all 0.5 to 2.5 bar leds are off, check the
water pressure transducer connection.
Flashing red led, water
pressure is too low (*)
Flashing red led, flame detection circuit fault
Flashing red led, heating sensor fault (SM)
Flashing red led,
plant safety
valve tripped (*)
Fig. 15
11
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