Biasi 24s Intermittent No Fan No Flame

[Southhill]

Hi

We have an intermittent fault with our Biasi 24s, being intermittent it's hard to diagnose.

When using either hot water or central heating, sometimes the boiler doesn't fire and the lock out light comes on. Pushing the reset sometimes works, generally not. After a few hours it works again! Sometimes this will happen a few times a day, or occasionally over a few days, then not for weeks.

The pump runs but the fan doesn't, then it locks out.

One time when it did this I had the time to go through the whole fault finding list, checked everything, diverter microswitch operation, various other voltage and switching checks and concluded it was the air pressure switch. I replaced this and it worked fine.....for about four weeks. Oh, replaced the diverter diaphram about 2 years ago.

Now the problem is back.

I called Biasi's help desk and they basically said, 'if it's an intermittent fault, it's hard to diagnose'....yes... So couldn't really point me to what it could be, other than to say clean the venturi. But surely this would have no effect until the fan runs.

So, what's stopping the fan from coming on which only happens now and again, particularly at bath time!

Thanks for your help.

 

[Boilerman2]

Cannot give advice relating to Gas work

however I suspect the problem will be to do with APS

Must be repaired by Gas Safe Register Recognised Engineer Only!!

 

[Agile]

The forum rules are very clear that we do not give advice on DIY gas/safety related aspects.

The obvious solution is to get a registered engineer.

Tony Glazier

 

[Southhill]

Cannot give advice relating to Gas work

however I suspect the problem will be to do with APS

Must be repaired by Gas Safe Register Recognised Engineer Only!!

Thanks for your response. I don't think this is gas related, more electrical. I don't know what the APS is? Another thing that happens sometimes is that when I turn off the hot tap, the flame goes out but the water continues to circulate in the boiler. I have to turn the tap on and off again quickly, then it stops.

Any further thoughts?

 

[Southhill]

Cannot give advice relating to Gas work

however I suspect the problem will be to do with APS

Must be repaired by Gas Safe Register Recognised Engineer Only!!

Thanks for your response. I don't think this is gas related, more electrical. I don't know what the APS is? Another thing that happens sometimes is that when I turn off the hot tap, the flame goes out but the water continues to circulate in the boiler. I have to turn the tap on and off again quickly, then it stops.

Any further thoughts?

OK, just checked, APS = air pressure switch. I changed this as mentioned in my original post.

Any further thoughts?