Checking The Temperature - Biasi M110.24SM/E Service Manual

Electronic control/ignition p.c.b.
tiometers etc.) others, like the fuses, are accessible by
removing the service panel.
1 2 3 4
18 17 16 15 14
Fig. 9.2
1 x7 connector --- electric supply terminal block and
external controls terminal block.
2 Fuse F1, F2 3,15 A F
3 Fuse F3, 400 mA T
4 x12 connector --- pump and 3way diverter valve
5 x17 connector --- gas valve
6 x14 connector --- external temperature probe
(optional)
7 x9 connector --- safety thermostat, flue tempera-
ture probe NTC, c.h. temperature probe NTC
8 x11 connector --- d.h.w. temperature probe
9 x10 connector --- d.h.w. flow switch
10 x2 connector --- timer
11 Lock ---out signal lamp
12 Boiler reset button
13 Function control / C.h. temperature adjustment
14 x22 connector --- fan
15 x24 connector --- transformer
16 D.h.w. temperature adjustment
17 x5 connector --- transformer
18 Appliance operation lights
9.3

Checking the temperature

The Electronic control/ignition p.c.b. makes it possible
to separately adjust the c.h. water flow temperature and
d.h.w. outlet temperature.
16
5 6 7 8
13 12 11
The temperature of the water is converted into an elec-
tric signal by means of temperature probes.
The user, setting the desired temperature with the con-
9 trol panel knobs operates the variable elements (13 and
16 in Fig. 9.2) of the electronic control p.c.b.
If the power requested is lower than 40% of the maxi-
mum power output then control is achieved by switch-
ing ON the burner at minimum power, then switching
OFF (ON/OFF function). If the power requested is
higher, then the burner is switched ON at maximum
power and will control by modulating to 40% of the
maximum power output.
During the c.h. operation (Fig. 9.3), the signal coming
from the c.h. temperature probe is compared to the sig-
nal given by the control panel through the adjustment
made by the user (knob
10
comparison operates the fan speed thus regulating the
gas flow rate and consequently changing the useful
output of the boiler.
Fig. 9.3
When the boiler functions in d.h.w. (Fig. 9.4), the signal
coming from the d.h.w. temperature probe is compared
). The result of such a