Constant Central Heating

Oakwood · 22 Jan 2011

Hello everyone

A couple of nights ago our central heating didnt switch off and now stays on 24hrs, irrespective of what we do with the control panel or thermostat.

The timer can be set to off, we can actually turn it off, and we can turn the thermostat right down - and whilst the panel doesnt seem to think the heating should be on (ie no red light), the boiler cracks on and the rads remain on.

So we have resorted to simply having to shut the boiler off as thats the only way to stop the rads. Fortunately, we have an electric shower for the morning, and we then turn the boiler back on in the late afternoon for water and heating in the evening before switching it off when going to bed.

Clearly not sustainable a solution! Any ideas??

We have a HORSTMANN CENTAURPLUS C27 panel if that helps. We only bought the house last year, but the notes that we have indicate that it was only installed in December 2004, along with a new boiler and a new sealed CH tank system.

Any help - very much appreciated!!

Thanks,

plumbnuts · 22 Jan 2011

What boiler is it and do you have a hot water cylinder?

Oakwood · 22 Jan 2011

Thanks for the swift response! We have a Potterton Suprima 60L located in our basement - in the airing cupboard down there we also have a big cylindrical tank, which I presume is a hot water cylinder. Thanks again

45yearsagasman · 22 Jan 2011

This screams faulty motorised valve to me.

Oakwood · 22 Jan 2011

Hello 45yearsagasman - nice to hear from you again!

A faulty valve sounds like a major problem, and not one to be fixed by inexperienced hand. Is there anyway I could confirm this as the cause before getting someone around to fix it?

Thanks again,

Oakwood · 22 Jan 2011

bit more info in case it helps...

After having the boiler off since last night, I just now turned the CH to 'timed' on the control panel, but ensured that the system was not actually timed to come on, i also turned the thermostat right down.

I then turned the boiler back on - nothing. I then turned the thermostat up - still nothing. Then turned the CH to the 'on' setting - sure enough the boiler fired up. However, I then turned the thermostat right down as far as it will go - boiler still going. I then turned the CH system to being off altogether, but the boiler is still going with the rads starting to warm up as i type, despite the CH system being off (according to the control panel) and the thermostat being turned down as far as possible.

It almost seems like the boiler wont just start by itself after being turned on, and will only start (as per the norm) when the control panel tells it to kick in, however, the control panel and the thermostat have seemingly then lost the ability to tell the boiler to shut down, resulting in it staying on constantly once its started up...?!

Hope that helps you experienced gents help me...!

45yearsagasman · 22 Jan 2011

More info on your system controls would help:-
Do you have one of these View media item 30313
Or maybe 2 of these View media item 30391

Oakwood · 22 Jan 2011

Definitely recall having a metal box contraption connected to a pipe in the airing cupboard, but will go and have a rumage around to see what i can see and report back shortly...!

Oakwood · 22 Jan 2011

Have had a good look around and can only see one motorized valve. It doesnt sit at the top of a T-junction of pipes, but just alongside a continuos stretch.

It is a Honeywell V4043H1056 and has a metal switch on the bottom for 'auto' and 'manual open', and which is currently set to auto.

Do you think this is the problem?

Thanks again for all your help

45yearsagasman · 22 Jan 2011

Thats a 2 port valve and usally there are 2,one for ch and one for hw.
I would suspect that one of these is faulty,either siezed or with a faulty microswitch.Either way to test them you need a meter or suitable voltage tester and a fair understanding of system wiring.For a pro it would take no more than 15 mins to find.

Oakwood · 22 Jan 2011

can only see one, but will have another good luck in the airing cupboard - which is pretty pokey and doesnt have a light! Is it possible /common for the second to be tucked away completely out of sight, perhaps under the flooring?

So do you think we need a sparky, rather than a plumber to look into this problem?

45yearsagasman · 22 Jan 2011

These valves are sometimes hidden.A heating engineer should have the skills to find the fault and be able to change/fit parts as required be it electrical or water parts.

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Constant Central Heating

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