Biasi M90F 28S

[DaveMak]

My boiler occasionally (but annoyingly more frequently) fails to ignite on DHW. It never fails on CH. It will sometimes go weeks without failing then will have a few weeks failing virtually every time on DHW.
Only way to get hot water then is to turn on CH, then open tap and turn off CH at which point the DHW stays lit and you get your bath.
Any ideas guys ???

 

[picasso]

its probably the electronic flow switch that has failed.

 

[DaveMak]

Thanks picasso for that.
Does that only affect the DHW and not the CH?
Also is it an aesy job to change?

 

[picasso]

yes and yes

 

[DaveMak]

Thanks yet again picasso - I'm on the case.

 

[Agile]

Let me know when you need advice to fix it.

Tony

 

[picasso]

Let me know when you need advice to fix it.

Tony

why ? was I wrong.

 

[Agile]

I dont know as I have not been there.

But I expect that you have correctly guessed what is not operating but not why!

I have only once found a faulty switch and that was a subminiature one on a plastic plastic group.

Tony

 

[picasso]

I am guessing that the float is stuck inside the flow switch, the op asked what was not working not why.

 

[Gasguru]

I'm guessing the primary flowswitch operation may be marginal in DHW mode..OP says if the boiler is initiated with a heating demand then the hot water works ok.