3.2
TEMPERATURE SENSOR
AND WATER PRESSURE
TRANSDUCER
Antifreeze system made up of the NTC hea-
ting sensor that activates when the water
temperature reaches 6°C.
Tables 3 - 3/a
show the resistance values
(
Ω
) that are obtained on the sensor as the
temperature varies and the transducer
values obtained as the pressure varies.
When sensor (SM) is interrupted, neither
of the boiler's heating services will func-
tion. With D.H.W. (SB) sensor interrup-
ted, the boiler will only work in heating
mode.
3.3
ELECTRONIC IGNITION
Ignition and flame detection is controlled
by two electrodes located on the burner.
These guarantee maximum safety with
intervention times, for accidental swit-
ching off or gas failure, of within one
second.
3.3.1
Operating cycle
Rotate the selector knob to summer or win-
ter, and verify that green led (
) lights up to
confirm the presence of voltage.
The boiler is now ready to start working
upon demand for heating or drawing off
of D.H.W.; a discharge current is sent to
the ignition electrode through the pro-
grammer, and the gas valve opens at the
same time. The burner must be ignited
within 10 seconds. However, it is possible
for ignition failures to occur, with conse-
quent activation of signal indicating that the
control box has “locked out”.
–
Gas failure
The control box runs through the cycle
normally sending electric power to the
ignition electrode. The electrode conti-
nues spark discharge for a maximum of
10 sec.If the burner does not light, the
lock-out indicator will light up.
This may occur upon first ignition or
after long periods of boiler lay-off when
there is air in the pipes. It may be caused
by the gas cock being closed or by one of
the valve coils having a break in the win-
ding, so that the valve cannot open.
–
Ignition electrode fails to spark
15
13
1
3
5
7
8
9
10
11
12
14
6
6
10
Fig. 19
TABLE 3 (Sensors)
Temperature (°C)
Resistance (
Ω
)
20
12.090
30
8.313
40
5.828
50
4.161
60
3.021
70
2.229
80
1.669
TABLE 3/a (Transducer)
Pressure
Resistance (
Ω
)
(bar)
mín
máx
0
297
320
0,5
260
269
1
222
228
1,5
195
200
2
167
173
2,5
137
143
3
108
113
3,5
90
94
KEY
1 Ignition electrode earth faston
3 Fuse (1,6 AT)
4 Fuse(0,16 AT)
5 “ANN. RIT.” connector
6 “POT. ACC.” trimmer
7 Conector “MET-GPL”
8 D.H.W. potentiometer
9 Detector electrode faston
10 “POT. RISC.” trimmer
11 C.H. potentiometer
12 Selector CR/OFF/EST/INV/RESET
13 DIP SWITCH
14 Connector “Modureg Sel.”
15 Connector “Albatros”
NOTE: To gain access to trimmers (6) and (10), unscrew the central heating potentiometer knob.
19
