Radiator cold at bottom

cazs

One of my radiators is warm at the top yet cold at the bottom. I tried bleeding it and there was no air escaping - the water started to come out straight away so I tightened it right back up again. It has made no difference even after I gave it some time. Any advice please?

Froglet

Turn off the central heating then go round and turn off all your radiators except for the one that is not getting hot.

Turn it back on,and turn up the temperature to a bit higher than normal.This should force any air lock in the system out and should soon sort it out.Then put the others back on,but not on full,i assume you have thermostatic controls on them? Turn to about medium and tweak as necessary to avoid this happening again.

Always works for me if i get a problem with one of ours.It is usually the last one on the system that it happens to.

Ruski

Sludge in the radiator. Needs cleaning out.

HTH

Russ

LSfan

Froglet wrote: »

Turn off the central heating then go round and turn off all your radiators except for the one that is not getting hot.

Turn it back on,and turn up the temperature to a bit higher than normal.This should force any air lock in the system out and should soon sort it out.Then put the others back on,but not on full,i assume you have thermostatic controls on them? Turn to about medium and tweak as necessary to avoid this happening again.

Always works for me if i get a problem with one of ours.It is usually the last one on the system that it happens to.

Air doesnt sit at the bottom does it? - air rises to the highest part hence when when rad is cold at the top you bleed to get rid of the air.

as OP stated its more than likely sludge. Rad needs remvoing and flushing

sk240

If its got a TRV it could be set too low.
It could have sludge in the bottom.
The lockshield valve might be closed off too much not letting enough water flow through it.

Ebe_Scrooge

When a rad is hot at the bottom and cold at the top, that's air in the rad and is cured by bleeding. Cold at the bottom, more often than not it's sludge, as others have said.

Pretty easy to deal with. Close off both valves ( noting the position of the lockshield valve, i.e. count how many turns it takes to close it ). Unscrew the pipe from the bottom, having first placed a large bowl and plenty of rags to catch the water. Handy to have an assistant ready with another couple of bowls, most rads will contain more than a washing-up-bowl full of water.

When it's empty, unscrew the other pipe, lift it off the wall, carry it outside, making sure you've got your thumbs over the two holes to stop drips of mucky water all over the carpets.

Flush it through with a hose - be thorough, hose in at both ends, hold it right way up and upside down, swish it around, etc.

When all the water comes out clear, take it back inside, reconnect it, open the valves ( lockshield back to it's original position ), open the bleed key and let it fill up. Keep an eye on your pressure at the boiler, you'll probably need to top the system up. Job done. Perhaps not as thorough as a power flush, but zero cost and probably near enough if it's just the one rad.

Many many years ago I had an old house, the whole system was gunged up. Really could have done with a power flush, but I was totally skint. So me and a mate did every radiator in the house as described above. Took maybe four or five hours to do the lot, and it worked fine after that. OK, there's going to be some residual muck in the pipework that'll find it's way back through the system, but the bulk of it collects in the rads.

Hope this helps.

Confused62

Hi


I am new to this forum so hope somebody will be able to help me please


We are having problems with our central heating. The boiler keeps cutting out.


Our house is rather large - 5 bedrooms and probably 20 radiators in all. Boiler is 21 years old (header tank in loft)


Engineer just been out and says we need a power flush. Radiators hot at top and cold at bottom means system full of sludge. Has fitted new pump but still says it is a circulation problem. He is coming back tomorrow to fit a new bit in the boiler just to make sure the cut out/overheating switch isn't faulty.


I have been reading the various posts about power flushing and lots say we can do it ourselves but we are both pensioners and don't feel we would be able to do it.


Any advice would be appreciated please


Thanks

Yorkie1

Was it a British Gas engineer?