Bottom of radiators are cold Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[colm]

I have a gloworm 40/52 floorstanding boiler. I think that the heating system is sealed/or direct feed (if there is such a thing), as there appears to be no expansion tank.
There is a cold water tank in the airing cupboard above the hot water cylinder and I am certaian that the hot water is a gravity system.

The problem is that the bottom of my radiators are cold, some are tepid some are stone cold, while the tops are warm to hot and this is with the thermostat up full.
The pump is in the boiler, it has two speeds and is on the higher speed.
The cold tank in the airing cupboard has an open pipe curved over pointing into it. That pipe has a spur that has a smaller 1/2" pipegoing around the back of the cylinder and down again into the floor space above the downstairs ceiling.
I've read many postings about cold tops to rads not cold bottoms. Does anybody have any ideas. If they need flushing how's it done.
Thank you in advance.

[wookey]

Cold bottoms of radiators suggests sludge in the system. And that implies flushing/cleaning. I'm in the middle of this myself (in preparation for fitting new boiler). I found useful info here:
[url]http://www.fernox.com/?cccpage=DS40&sub=1[/url] ,


here: [url]https://www.diydoctor.org.uk/projects/bleedrads.htm[/url]
and here: [url]https://www.diydoctor.org.uk/projects/drainch.htm[/url]

I'm not sure from your description what sort of heating system you have, beyond that the 'cold water tank' in the airing cupboard sounds like a 'feed and expansion tank' which is most likely to be there to top up the CH system. In this case flushing is easy. See the links above.