Expansion pipe discharge when heating turns off

jfk

Hi I have a problem with the header tank to the central heating overflowing. I have drained and run the system through and refilled. I have now noticed that at the point of the heating turning off it discharges water into the the heating header tank.
I have also noticed that the radiator closest to the airing cupboard only warms through one pipe, this is also the same with the hot water cylinder. The top pipe entering the coil is hot, the bottom is cold (luke warm at best).
Any advice on how to test and rectify the problem, I have considerd that their may be a blockage in the feed pipe but would like advise before changing pipes.

Dan_Robinson · Posted: Fri Jul 27, 2007 10:07 pm Post Subject:

Sounds like a sludge problem as well as a possible pipe layout problem. Any pictures available?

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Dan Robinson

If I was right half as much as my wife was wrong I'd be a very happy man

jfk · Posted: Sat Jul 28, 2007 7:46 am Post Subject:

Sorry no pics, the feed is 15mm dropping down in to the heating system and t`ing of to the lower pipe entering the coil, expansion runs on 15mm t`ing of to the pipe entering the top part of the coil. Would you think the blockage was somewhere along the 1st section of feed before exiting under the floor in airing cupboard.
My 1st theory was to replace the pipework running from header tank down and upto the rad next to airing cupboard that heats only through the one pipe?

Dan_Robinson · Posted: Sat Jul 28, 2007 11:04 am Post Subject:

Quote:

expansion runs on 15mm t`ing of to the pipe entering the top part of the coil

That's not good for a start.

Should be 22mm.

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Dan Robinson

If I was right half as much as my wife was wrong I'd be a very happy man

gas4you · Posted: Sat Jul 28, 2007 6:50 pm Post Subject:

Is this an old gravity primary system or fully pumped? If fully pumped I would replace pipe work to header tank and install an air seperator such as a Myson Aerjec.

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Dave
DRL Gas Services

jfk · Posted: Sat Jul 28, 2007 7:32 pm Post Subject:

Hi I fought it should have been 22mm.
It is an old system. Their is no 3 port valve in the airing cupboard infact im not sure where it is and their is a pump which is down stairs above the boiler.
It apparantly used to work fine untill she had someone in to power flush the system (sounds like a bodge flush tho they had to replace the pump the next day probably didnt bleed it).

gas4you · Posted: Sat Jul 28, 2007 7:33 pm Post Subject:

Do you have 4 pipes coming off the boiler or 2?

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Dave
DRL Gas Services

jfk · Posted: Sun Jul 29, 2007 11:18 am Post Subject:

2 pipes flow and return its an old glow worm boiler but not sure wich model.

gas4you · Posted: Sun Jul 29, 2007 11:32 am Post Subject:

Sounds like a very basic pumped system then.

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Dave
DRL Gas Services