Expansion tank feed to radiators blocked?

[twigged]

Hi,
Our Potterton Prima F has been acting up for the past few weeks, rattling a bit and ocassionally cutting out (the electrics seem to work - boiler fan, pump stay on but the flame remains out and won't relight unless I power it off and on again). We've had an engineer out to look at the boiler and he can't see any issue with it, it was serviced a few months ago as well so I think the problem might lie elsewhere.

From reading posts on this site (very useful) I suspected the pump or air / sludge in the system. I've tried bleeding the radiators but now a few upstairs refuse to bleed. I think the expansion tank in the loft may have a blocked pipe to the radiators - the water in it contains lots of lumps of brown particles. I bled about half a pint of water from one of the downstairs radiators but didn't see any movement in the expansion tank. Cold water will fill in though if I shove the ball cock down.

Now the odd thing is the water I drained from the radiator is practically as clear as crystal. So to fix this, would it be over the top to get a powerflush of the system done, or would there be an easier way to clear the blockage out?

 

[seco services]

you can remove the blockage yourself from the cold feed it useally occurs where the feed joins the rest of the system.

then use some sentinel x800 or x400 in the system for a few weeks then drain.

 

[twigged]

Thanks - I've cleaned out the header tank, what a way to spend a Sunday. Over the weekend though the boiler looks like it's totally died - thermostat or something I suspect - time to get heateam out I guess...

 

[JohnD]

cleaning the mud out of the "header tank" (Feed and expansion) is a start, but the blockage in the pipe might mean your system is short of water so the boiler will not fire.

If you are fond of DIY plumbing you can fix the blockage yourself. Once you have done that you can set to work de-sludging the system.

Many professionals will remove the blockage for you and will then recommend a Powerflush at some hundreds of pounds. This is not wrong, but it is worth trying the DIY route first as it may get it working and save you money.

Most likely the blockage will be at the Tee joint where the 15mm pipe from the F&E joins onto the big circulating pipe, probably near the pump. If you hold a magnet to this joint it will probably be attracted to the black iron oxide sediment lump inside.

If you want to DIY we can describe how - it is a very common problem.

I am just a householder.