Boiler won't stop firing up.

[Worrier61]

Hello.
We have recently had our 13yr old Biasi combi repaired (new heat exchanger, divertor, and motor).
Hurrah we now have hot water and heating. However the only way to turn it off seems to be at wall ie no hot water.
When the thermostat iis turned off, it communicates this properly. The boiler initially stops, then goes into a confused cycle of firing up (can see flame) then realising no demand so stopping, then firing up,....
Switching off at control panel does not stop it only the mains.
Not ideal but better than no boiler at all..
Don't want to leave it in endless cycle as this feels like it would cause wear and tear plus be an expense.
Any ideas.
Thanks in advance

 

[jackthom]

Sounds like the hot water flow switch thinks a hot tap has been turned on and is firing up the boiler.

If it has been like this ever since the repair, you should really ask whoever did the work to come back and sort it out.

 

[terryplumb]

In central heating mode does it run normally ?
What model biasi do you have ?

 

[Worrier61]

In central heating mode does it run normally ?
What model biasi do you have ?

It's a Biasi
M96 28SM/C2
When we want the heating on it does *seem* to run normally.

 

[Worrier61]

Sounds like the hot water flow switch thinks a hot tap has been turned on and is firing up the boiler.

If it has been like this ever since the repair, you should really ask whoever did the work to come back and sort it out.

Thanks for the hint about a switch. My fear is that they may claim this is a new separate problem from the job done. We were so delighted that the heating worked (as he had temporarily set it to hw only) that it is hard to say when this problem occurred or is related to job done.
Background is that boiler kept tripping, so during a callout he set it so that at least we had running water while he waited for parts.
Finally not to give red herring but it did feel like boiler was directly responding everyone I paused dishwasher and that's a cold water feed. But a change in pressure might create a confusion with a sensor?

 

[terryplumb]

You need to get the engineer back ,who should have left you with a fully working boiler ! It sounds as if that wasn't the case.

 

[Worrier61]

Thanks for the answers so far.
I have contacted them. My fear is that they may consider it a new job.
I don't know how much testing was done as the job was done when I was out. Infact I wasn't sure if he was half way through or done as there was no communication. I had to contact him and ask if I could turn it on!
If if is to do with hot water flow switch, and that very much seems like it could be to this amateur anyway..
Is it a cheap easy part, or even better is it the type of thing which just needs adjusting. Sorry if that is a stupid question. I have no idea what that part looks like. About to educate myself on YouTube!

 

[CBW]

Sounds like you have no trust in your engineer, it could be something overlooked, but could be a new failing part.

 

[Worrier61]

Sounds like you have no trust in your engineer, it could be something overlooked, but could be a new failing part.

Well!
In a rural area people weren't fighting to come out. I had to go with whoever was prepared to fit me in. I often lose confidence in a tradesperson when there is poor communication. Some would say I expect too much.
Understand that you can't say.
Hoping it not a replacement part. I can imagine having to pay a callout, then waiting a week for them to acquire part, and so on.
I couldn't replace the heat exchanger (one of the initial problems because it was simply too inaccessible for me). Then there was a second tripping problem. Hence the job done. If a flow switch is easy to replace I would do it myself. Anyway please forgive my rambling. Thanks.

 

[Worrier61]

Have still not heard back from engineer.
May I ask a final question as I suspect they'll claim it's a new problem. Presently heating works but when it would normally be off because temperature is reached, it still fires up (as if expecting hw perhaps). Could this in any way be related to the fitting of a new divertor?
If not and it's a flow switch, is this an easy job to do. I'm not quite at point of wanting a new boiler, but I also don't want to throw good money after bad. Thanks