H .W . Flow Switch, Filter And Flow Limiter; Function; Description And Location Of Parts - (Figure 14.2); Removal Of The Sensor - Biasi Advance Plus 25C ERP Service Manual

D.H.W. FLOW SWITCH, FILTER AND FLOW LIMITER
14 D .H .W . FLOW SWITCH, FILTER AND
FLOW LIMITER

14 .1 Function

The D.H.W. flow switch "A" in Figure 14.1 is a device that gener-
ates an electrical signal when hot water is drawn.
Figure 14 .1
When the flow rate through the D.H.W. circuit reaches about 2,5
litres/min', the sensor closes the electric contact that switches
the boiler D.H.W. operation ON.
14 .2 Description and location of parts - (Figure
14 .2)
1 Flow switch plug
2 O-ring
3 Flow limiter (Advance Plus 30C ERP - Advance Plus 35C
ERP optional accessory)
4 Body with flow meter turbine
5 Filter
1
2
3
Figure 14 .2
- 36 -

14 .3 Removal of the sensor

A
Figure 14 .3
1 Remove the front panel of the case.
2 Remove the sensor holder "C" and disconnect the connec-
3 Remove the sensor.

14 .4 Checks

5
4
2
Figure 14 .4
1 Remove the front panel of the case.
2 Don't disconnect the connectors "B".
3 Measure the electrical frequency at the leads of the sensor.
Warning: isolate the boiler from the mains electrici-
ty supply before removing any covering or compo-
nent .
tors "B" (Figure 14.3).
Warning: isolate the boiler from the mains electrici-
ty supply before removing any covering or compo-
nent .
Sensor operation
0..32 Hz
(without flow rate)
33..200 Hz
(witht flow rate)
wh = white
bu = blue
rd = red
Without flow rate the electrical frequency must be 0÷32Hz.
With flow rate the electrical frequency must be 33÷200Hz.
E
D
B
C
bu
wh
rd
B
5V
rd
wh
bu