Radiator hot at the top but cold at the bottom

[lisa.white2]

Hello, One of my radiator it hot at the top but only just warm at the bottom. My other radiators are all hot at the top and bottom. Can anyone tell me whats wrong. Thanks.

 

[boilerbeasty]

This happens when there's sludge collecting in the radiator. If you don't have anti-corrosion chemicals in the water in your central heating, the radiators corrode over time, and the sludge (essentially rust) collects somewhere. A solution is either to shift it with chemicals put into the water, which you allow to run around the system for a week, then rinse out and replace with clean water (+anti corrosion additive). Another is to water through the sludge by sheer force of water. This is a bit more messy/difficult and you can be charged a few hundred pounds for the service.
If its just one radiator, the easier solution could be to remove just that one and wash through, the use the chemical cleaning technique.

 

[lisa.white2]

Thanks the information I will give it a try.

Lisa