O Temperature Probe Ntc; Function - Biasi RIVA COMBI Service Manual

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Third Part
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Temperature Probe NTC

1) Function

2) Checks
3) Removal
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
resistance is stated in Figure 1.
On the boiler there are two Temp. probes. One
on the output of the primary heat exchanger (c.h.
NTC) A in Figure 2; one on the bottom of the
d.h.w. storage tank (d.h.w. NTC) B in Figure 2.
RIVA COMBI SERVICE MANUAL – REV A
Figure 1
B
A
Figure 2
(edition-0106)
2 Checks
A Temperature-resistance relationship
Warning: Isolate the boiler from the mains
Disconnect the cable from the Temperature
probe.
Measure the temperature of the brass group
where the Temperature probe is located and
check the electrical resistance according to the
graph in Figure 1.
If the temperature that the NTC give to the
control p.c.b. is more than 100°C, the NTC is
probably in short circuit.
If the temperature that the NTC give to the
control p.c.b. is less than 0°C, the NTC is
probably disconnected or interrupted.
3 Removal
Warning: Isolate the boiler from the mains
1) To remove the Temperature probes remove
the front panel of the case.
2) To remove the c.h. NTC empty the primary
circuit of the boiler. To remove the d.h.w.
NTC empty the d.h.w. circuit of the boiler.
3) Remove of the c.h. NTC:
Remove the electric connector of the NTC
probe C and unscrew it (Figure 3).
4) Remove of the d.h.w. NTC:
Remove the fork that blocks the probe cable.
Pull downwards the cable connected to the
Temperature Probe NTC
electricity supply before removing
any covering or component.
electricity supply before removing
any covering or component.
Figure 3
C
12-1