radiator Hot at Top Cold at Bottom.

[robertjp123]

I Have just replaced a old radiator in my living room,my system was drained down last summer by plumber,my new rad is hot at the top and cold at the bottom,would this be sludge as the water was running clear before i put it on. i did not drain the system because i used pipe freeze. i have bleed the rads and they all seem to be working fine,just my new one not working as should,i have bleeded the new one too and no air comming out. oh i used 15mm / 1/2" felx pipe with built in isolator valve Any advise would be fantastic.

[alavahalf]

Am I reading this right...you have used a flexible hose to supply your radiator...if so you really need to remove it as these are only used to supply water to a sink, basin, bath or cistern. A flexi hose may restrict the flow of the water to a radiator.... and as we all know...hot water rises, this will heat the top of the rad leaving the bottom cold. The fact that it is hot at the top, tells you air in the rad is not your problem.
Draining the system does not remove sludge. You would need to add a system cleanser, and run it in the system for a given period of time. This may help to cleanse the system. But it will never do the same job as a power flush.
It sound as though there may be a flow problem, if you have got a flexi pipe, I really think you should replace it with poly plumb, or hep 2o plastic fittings to increase the flow through the rad... easy d.i.y. option
As I don't have all the info...before you get involved in pipework....at one end of the rad you will have a lockshield valve..try giving it a 1/4 turn anti-clockwise, if it will go....this would also increase the flow.
Let us know on your progress...

Try the lockshield first ...snows on the way..

[robertjp123]

The snow is here :( , ok i wil remove the flexi pipes and go with solid,i am hoping this will be the awnser.
Thank you very much to take the time to reply and help.
Stay warm.