Temperature Probe; Function; Checks - Biasi Activ A 12OV Service Manual

9

Temperature probe

9.1

Function

The Temperature probe has the function of converting
the temperature of the water in the hydraulic circuit
where it is installed into an electrical signal (resistance).
The relation between temperature and electrical resis-
tance is stated in Fig. 9.1.
Ω
12500
12000
11500
11000
10500
10000
9500
9000
8500
8000
7500
7000
6500
6000
5500
5000
4500
4000
3500
3000
2500
2000
1500
1000
500
20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100
Fig. 9.1
On the boiler there are two Temperature probes. One
on the output of the primary condensing heat ex-
changer (c.h. flow Temperature probe) A in Fig. 9.2 and
Fig. 9.3; one on the inputof the primary condensing
heat exchanger (c.h. return Temperature probe) B in
Fig. 9.2 and Fig. 9.4.
Fig. 9.2
c.h. c.h.
flow return
A
B
9.2

Checks

Temperature---resistance relationship
n
Warning: isolate the boiler from the mains
electricity supply before removing any
covering or component.
Disconnect the cable from the Temperature probe.
Measure the temperature of the pipe C (c.h. flow Tem-
perature probe)(Fig. 9.3) or of the pipe D (c.h. return
Temperature probe)(Fig. 9.4) where the Temperature
probe is located and check the electrical resistance ac-
cording to the graph in Fig. 9.1.
9.3
Removal of the c.h flow Temperature
probe
Warning: isolate the boiler from the mains
electricity supply before removing any
covering or component.
1 Remove all the case panels.
Remove the electric connector E and remove the
2
c.h. Temperature probe A --- Fig. 9.3
3 Reassemble the c.h. flow Temperature probe
carrying out the removal operations in reverse
˚C
order.
Fig. 9.3
9.4 Removal of the c.h. return Temperature
probe
Warning: isolate the boiler from the mains
electricity supply before removing any
covering or component.
1 Remove all the case panels.
2 Remove the electric connector F and c.h. return
Temperature probe B --- Fig. 9.4
3 Reassemble the c.h. return Temperature probe
carrying out the removal operations in reverse
order.
E
A
C
25