Sime OPEN.zip 25 BF TS Instrucciones Para El Instalador página 65

3.3 ELECTRONIC DIGITAL DEVICES
Ignition and flame detection is controlled by a
single electrode placed on the burner, which
guarantees maximum safety with interven-
tion times, for accidental cut-off or lack of
gas, of within one second.
3.3. 1 Function cycle
The electronic digital device SIT 0.577 cod.
6210208A repeats the ignition cycle, of
about 10 seconds, for no less than three
times before boiler functioning is shut down.
The delay time between each ignition cycle
is 15 seconds with the ventilator continuing
to function. The complete cycle therefore
takes 60 seconds before the shut-down
signal is activated. Ignition failure with con-
sequent activation of the shut-down signal
can be summed up as follows:
- No gas
The ignition electrode consists in comple-
ting the entire cycle; if the burner does
not start, the shut-down signal is activa-
ted.
When switched on after long periods of
non-use, there may be air in the pipes.
The gas tap may be closed or the winding
of one of the valve coils may have been
interrupted, thus preventing opening.
- The electrode does not produce the
discharge
In the boiler, only the opening of gas to
the burner will be seen, and after the full
cycle the boiler is shut-down.
Alternatively, the electrode wire may be
interrupted or not firmly fixed to the termi-
nal of the appliance; or the appliance tran-
sformer is burnt out. The electrode is
earthed or it is worn out, and it must be
replaced.
In the case of a sudden lack of voltage, the
burner will switch off immediately; when vol-
tage returns, the boiler will automatically
start working again.
3.3.2 Function cycle
At every start-up cycle, the electronic device
checks the situation and in the case of
breakdown or parasite flame signal, pre-
vents start.-up.
The apparatus will not start up also if the air
pressure control device is not in the no-ven-
tilation position.
3.4 FUMES PRESSURE VALVE
The fumes pressure valve is set in the fac-
tory at the optimal values of: 5.3 - 6.3 mm
H O in model "25 BF TS" 3.6 - 4.6 mm H
2
in model "30 BF TS", which will guarantee
boiler function even with discharge piping of
the maximum length allowed. If the burner
does not start up, check the value of the
pressure valve signal by means of a special
instrument linked to the pressure tapping
points (fig. 12). In the case of an insufficient
signal, check charge loss of the fumes duct.
3.5 ANTIFREEZE PROTECTION
An exclusive antifreeze system provides for
automatic switch-on of the main burner
when the sanitary or heating water sensor
registers a temperature of less than 4°.
When only one sensor registers a tempe-
600
500
400
300
200
100
0
O
2
rature lower than the set limit, the boiler will
start working. In antifreeze mode, the pri-
mary circuit temperature does not exceed
50°C. However, the boiler always needs
electricity.
Even if there is no gas the antifreeze system
will activate the circulator. This system only
guarantees the boiler.
3.6
The residual discharge head for the heating
plant is shown, according to flow capacity, in
the graph in fig. 13.
30-35
25
25
200 400 600 800
Fig. 12
DISCHARGE HEAD AVAILABLE
TO THE PLANT
By-pass inserito
By-pass inserted
By-pass escluso
By-pass excluded
30-35
1000 1200 1400 1600
FLOW RATE (l/h)
PORTATA (l/h)
Fig. 13
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