Central Heating

[enfable]

One of my radiators is getting warm at the top but not at the bottom, whislt the rest are working fine.

The system is only around 5 years old and the boiler seems to be working as it should. The radiator that is not heating up properly is, I believe, the last one in the systems chain (furthest from the bolier). Upon bleeding the radiator the water coming out is warm / hot but the radiator is only heating up at the top. Anybody know how I can fix it?

If I can't fix this myself does anybody know what I should expect to pay a professional to fix it?

[The Builder]

The first thing I would think of would be air in the rad, but you say bleeding doesn't help. Being the furthest rad from the boiler, perhaps the rads need balancing. Possibly the hot water "runs out of steam" before it reaches the furthest. Simply, the other rads are taking too much of the available heat.
This could also be that the pump is set too slow. Also, is the boiler 'stat turned up enough.
It shouldn't take a heating engineer long to figure it out.

[tezestwing]

Hi you could turn down all the other rads to minimum on there TRVs so that you create a good flow to the rad in question and see if that improves, if it does and i bet it will, then you defo need to balance the system as The Builder says and is covered by lots of replies on this site and is not to complicated it involves going round and adjusting the lock shield valve (op end to the TRV) to close down or open up the valve the close down ones are the closest to the boiler,after removal of the plastic top you must only turn the center spindle with the square top anti clock to open clock to close you could use a small adjustable spanner with care if it wont move dont force it they are prone to seizing up apply penetrating oil and try later or seek advice the job is a balance exercise so could take a while to do HTH

[jomifl]

If the rad is getting warm only at the top it doesn't need bleeding, you may have a partial airlock in the pipes or there may be some sludge in the readiator valves. You may be able to force this through by closing of other rads one at a time so that the pressure to the rad increases. If it has an effect leave it for a few minutes for the pipes to clear then open the rads you have closed. If the cause of the problem was an airlock then you may have to beed the rad afterwards. When you close the rads use the shut off valves ( the ones that don't have a cap ) as you don't want to unbalance the system unnecessarily.