Biasi Boiler - Not Turning Off!

[Jabhead]

Hi,

I have a Biasi 24S combi boiler (the compact one).

Last night the boiler switched on for hot water and would not turn off!

It heats up the radiators regardless of settings (whether on summer mode, etc.) and whether or not the thermostat is turned up or down.

Anyone have any ideas? Seems like some sort of control problem!

Thanks in advance

 

[Agile]

This is not a 24S but an M90.

Sounds like the DHW demand switch is jammed on although if the boiler was in good condition that should not heat the rads.

If you undo two screws at top of front and raise it up you may see a small red LED illuminated behind the pump.

Tony

 

[Jabhead]

Okay - sounds like that might be the problem. I'll take a look this evening once back from work.

Assuming I do see the red LED illuminated what would you suggest? Is it an easy fix or better to get a gas engineer in?

Thanks

 

[Agile]

On the earlier model it needs a gas engineer as the gas valve has to be removed to access the demand switch. Even that is not so easy as it really needs a 24 mm hex socket or ring spanner whereas most now are 12 sided.

On later models there are two different types but both are usually assembled VERY tight indeed and can be a real paid to take apart. Often needing removing the entire RH hydroblock and using a vice and larger stillson!

Tony

 

[Agile]

On either type as a temporary solution you can remove the hall effect switch unit to enable CH to be resumed.

Tony

 

[Jabhead]

Fair enough.

I had a look last night and couldn't spot the red LED but having opened it up I think I'm going to need to get an engineer in - looks to be beyond my expertise, especially if a part needs replacing.

Thanks for the help - I notice you're based in London... whereabouts are you? And would you be interested in the repair? I'm presuming you are an engineer as you seem very knowledgeable!

Thanks

Jared

 

[Agile]

Yes, I am an engineer!

But if you wanted me to assist you then you need to contact me directly.

Double click on the "Agile" screen name and you can see my contact details.

It helps if you include your location in your profile rather then just UK.

Tony