Central heating question

[chrisrob]

I know if radiators are cold at the top they need bleeding as there's air above the hot water. But some of my radiators are cold at the bottom while hot at the top although feed and return pipes attach to the bottom. What should I do?

[terence7556]

its probable that they are sludged up with crap in the bottom. you may have to take them off the wall and clean them out using a hosepipe in the garden, through the openings in the bottom of the rad. time consuming but necessary maintenance.
afterwards youwill have to top up the inhibitor in the system.

[RAYMAN]

Just done exactly the same,while helping a friend to clean his,the cr*p that came out black oily slug.