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d.H.W. floW SWiTCH, filTER ANd floW liMiTER
14 d.H.W. floWMETER, filTER ANd floW liM-
iTER
14.1 function
The d.h.w. flowmeter A in Figure 14.1 is a device that generates
an electrical signal when hot water is drawn.
figure 14.1
A
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)
figure 14.2
2
1
3
4
2
5
1
Flow switch plug
2
O-ring
3
Flow limiter (optional accessory)
4
Body with flow meter turbine
5
Filter
14.3 Removal of the sensor
Warning: isolate the boiler from the mains electrici-
ty supply before removing any covering or compo-
nent.
figure 14.3
b
C
d
E
1
Remove the front panel of the case.
2
Disconnect the connectors B and remove the sensor holder
C (Figure 14.3).
3
Remove the sensor.
14.4 Checks
Warning: isolate the boiler from the mains electrici-
ty supply before removing any covering or compo-
nent.
Sensor operation
figure 14.4
wh = white
0..32 Hz
(without flow rate)
33..200 Hz
(witht flow rate)
rd
rd
5V
bu
bu
wh
wh
bu = blue
rd = red
b
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.
Without flow rate the electrical frequency must be 0
÷32Hz
.
With flow rate the electrical frequency must be 33
÷200Hz
.
14.5 Removal of the flow switch group and d.h.w. cir-
cuit filter
Warning: isolate the boiler from the mains electrici-
ty supply before removing any covering or compo-
nent.
