Top half of radiator hot

[Anteaus]

Situation: Large-ish (1.5m x1m) double radiator on microbore takeoffs from 15mm main feeds in hall. Inlet/outlet are at base. Rest of heating system works OK.

Only the top half of the radiator is hot, and its heat output isn't really enough to cope with the weather we're getting just now. Definitely not air (which would in any case cause cold top, whereas this is the reverse)

Any suggestions?

 

[stardanny]

Sludge at bottom of radiator.

Remove radiator, flush out, refix.

 

[JohnD]

poor circulation

might be sludge, rads need bancing, or pump not working properly, or too much flow going to cylinder (if you have one).

Turn off the other rads and see if this one gets hot.

If so, start by balancing.

Also, look at the similar topics at the foot of this page.

 

[gasandoilman]

could be air ?
It could be in the return pipework its very common
to rule this out turn all your other rads off so your heating pump is pushing through just that rad

 

[gasandoilman]

when bottom gets hot turn them back on

 

[Anteaus]

Thanks, will check these points.

 

[Grot]

Its bad news having a cold bottom