worcester bosch 240 wont switch off!

[peterb20]

Hi guys, problem with my boiler!

No matter what setting the control unit is set to (off, auto or on), the radiators are staying on 24hrs a day. Any ideas? i thought it might be a motorised valve, but cant see any that look similar to any ive seen before. Peterb

 

[ollski]

would imagine the flow switch is sticking on the hot water and going around the bypass keeping the rads topped up.

 

[peterb20]

is there any way i can check this? can i sort this without replacement of parts? if not which parts will i need to replace? Thanks for your quick reply, its really appreciated - getting through £100's per day at the moment probably!!

 

[ollski]

https://www.diynot.com/diy/threads/diy-gas.8090/

 

[peterb20]

sorry to be a pain, but what will the divert valve look like? ie how do i know which plug goes to the microswitch on the front of it?

And so if it is indeed the switch, then can i replace the switch, or the whole pcb?

thanks

 

[gblades]

https://www.diynot.com/diy/threads/diy-gas.8090/

 

[peterb20]

ok sorry for the delay in getting back to you all, but ive now tried the solution mentioned ( i presume ive done it correctly; the plug on the PCB was labelled flow switch so thats the one i unplugged!) and it didnt make any difference.

When i turn the timer dial on the front of the boiler through 24hrs, non of the 'on' or 'off' periods make any difference. I can hear the usual 'click' when it goes from on to off (or off to on) but this doesnt effect the boiler output. Only by switching the entire boiler off by the wall can i make it sound like its shut down.

Any body have any more ideas what could be causing my woes, or whether i cocked up the first solution i started my reply talking about?

Thanks alot in advance,
Peterb

 

[tomcart]

Hello,

Did you ever find a solution to this Peter? This is exactly what is going on my boiler at the moment. A plumber came round and thought it might be an issue with mechnical timer switch - but that seems fairly improbable to me from looking at the electronics. My boiler will switch off if the water is switched off as well as the central heating. If the hot water is switched on - then central heating and hot water are on. Info on any fixes you had would be appreciated. I will run through the above microswitch check when I get home.
Thanks in advance.

 

[peterb20]

no sorry no solution... A plumber came to look at it and basically the whole thing was goosed. There were about 5 different parts which needed replacing and in the end i just went for a new boiler sorry!

 

[mrdee0]

https://www.diynot.com/diy/threads/diy-gas.8090/

 

[BigglesTAP]

I have a similar problem to this except it is very intermittent. Flow valve was replaced not so long ago, the boiler i'snt that old, new programmer unit.
It seems to occasionally just stay on with the radiators stay constantly hot and not controlled by the TStat.
It did it the other day.
The boiler is in the garage so has a separate frost stat.
Both HW and CH lights on the programmer were off. Tested the frost stat and had to turn it way up to click. We had a colder night say 8c so no reason it would have triggered.
The HW and CH should have turned off but radiators still hot and hour of more after and boiler was firing up.
No control with the inside stat.
Boiler reset then off and on did not fix it.
I have a mains switch next to the programmer which when switched off and on fixes it and then I probably wont see the problem for months.
Been going on for a few years now.

 

[Dan Robinson]

the boiler i'snt that old

pahahahahaahah

 

[BigglesTAP]

That's helpful!!!!