H.w. Flow Switch, Filter And Flow Limiter; Function; Description And Location Of Parts; Checks - Biasi Activ A 25C Service Manual

14 D.h.w. flow switch, filter and flow
limiter
14.1

Function

The d.h.w. flow switch A in Fig. 14.1 is a device that
generates an electrical signal when hot water is drawn.
Fig. 14.1
When the flow rate through the d.h.w. circuit reaches
about 2,5 litres/min', the float 5 (Fig. 14.3) is dragged
upwards and the magnetic in it, getting closer to the
sensor 8 closes the electric contact.
C
Fig. 14.2
14.2

Description and location of parts

(Fig. 14.3)
1 Flow switch plug
2 O---ring
3 Flow limiter (Activ A 30C. Activ A 35C. optional ac-
cessory)
4 Body
5 Float
A
D
B
6 Filter
7 Sensor holder spring
8 Sensor
2
Fig. 14.3
14.3

Checks

Warning: isolate the boiler from the mains
electricity supply before removing any
covering or component.
Sensor operation
n
1 Remove the front panel of the case.
2 Measure the electrical resistance at the leads of
the sensor. Without water being drawn, the con-
tact must be open. By opening a hot water tap the
contact must be close (electrical resistance zero
Ω).
14.4 Removal of the
Warning: isolate the boiler from the mains
electricity supply before removing any
covering or component.
1 Remove the front panel of the case.
2 Disconnect the connectors B and remove the
sensor holder spring C (Fig. 14.2).
3 Remove the sensor.
14.5 Removal of the flow switch group and
d.h.w. circuit filter
Warning: isolate the boiler from the mains
electricity supply before removing any
covering or component.
1 Remove the front panel of the case and empty the
d.h.w. circuit.
2 Remove the sensor (see section 14.4).
3 Remove the fork D and pull up the flow switch
plug 1 with the help of a screwdriver.
4 To remove the filter from the flow switch group
separate the filter 6 from the body 4 (Fig. 14.3) by
levering it.
5 Reassemble the parts following the removing se-
quence in reverse order.
1
3
4
7
5
6
sensor
8
33