Alpha CB28 flow demand switch...Hmm

[Boothy999]

Morning all.

My central heating is powered by a n Alpha CB28. The radiator heating works fine.

The hot water has recently stopped working correctly, I noticed it wasn't starting the boiler when the tap's turned on. Read a little and bought a new flow switch, fitted it to the end of the circuit board wiring and it works fine (I left the old one fitted to the boiler and just manually operated it). When I physically swapped them over it still doesn't trigger the boiler to start. If the radiators have been on then warm water comes out, so i figure the heat exchanger is working ok.

Any ideas ? what actually switches the switch when in position ?

Thanks in advance.

 

[Boothy999]

By the time Id typed it all in it was afternoon, bugger

 

[terryplumb]

The flow valve ,within the diverter assembly operates the switch. The diapraghm may need replacing or its Gunged up and the spindle ain't moving freely.

 

[Boothy999]

cheers, ill take a look.