Cental Heating Question

[Rob Walford]

I have 3 radiators that are not heating properly. I ran the system though with some cleaner fluid. I have taken them off and flshed them with a pressure washer. I have checked the valves. Still having the problem, I then turned off all the other radiators, and ran the boiler. I then drained the system and the water was dirty, so i guessed that theer was still stuf in the pipes. I refilled, ran the system (still on the 3 rads) and drained again. I repeated this several times. I then ran a hose from the the drain tap to outside and turned on the filling loop. Now, heres my question. The water at this stage runs clear, even if it is still running at pressure through the system. If I repeat my refill-run-drain process as before, the water comes out a reddish colour. This seems to be improving the rads, they are a lot better than before.

Is it the case that water running through the system (3 rads still) is missing the dirt in the pipes, or is it the fact that the water is not going through the boiler and being heated that it is not coming out a reddish colour. I am going to be replacing my boiler soon, and dont want to fit it with dirty stuff in the pipes, but dont want to be flushing my pipes continuously if the boiler is the problem. Thanks in advance.

[*GED* THE BRICKIE]

It depends what you mean by dirty and if it was from the top of the RAD.Either your air locked which is what it sounds like,or BLACK sludge has settled along the bottom between the inlet and outward flow,if this is the case turn the water pressure off hot and cold just to make sure,pull all the carpets back.Cover the floors with old sheets etc,do this correctly on wooden or weyrock floors.Have some buckets ready or a drain hose whatever.Unfasten one pipe at a time you will need two of you for this.Stop the water running out with your thumb.Undo the next fixing nut with adjustables or monkey wrenches,carefully lift the RAD off its mounting brackets if you can get it to empty in the bath its easier,if not let it run into the buckets,repeat this with the others.Then take them out side and if you can flush them through with a hosepipe turned ful on.flush until they keep runing clean,hang them again wrap sealer tape round the threads bolt them back up,get the water hot run through air key them hot water is best.A word to the wise the newer the RAD the better sometimes they can rot from the inside where all the s**te has laid and this can leak making a mess.Its your decision but sometimes they are better left alone.IT should be ok though,and thats the reason why you shouldnt paint radiators.

[Rob Walford]

They were cold at the bottom. As I said, I have removed them, taken them outside and flushed them. The water is a reddish colour now. It was black/grey. The rads are better. They are still very slightly cooler at the bottom than at the top. Maybe this is normal?

[*GED* THE BRICKIE]

If all that did not work you have three blocked RADs One last thing you could try getting an old coat hanger,straighten it and try to loosen the sediment that way,otherwise replace them its not worth the risk of a LEAKDOWN,

[Bill]

Like a previous poster I suspect an air lock. Have you tried shutting every rad except one of the 'blocked' ones. Then switching on the heating for a few minutes. A mate had a similar prob once and that sorted in. The pipe runs in some systems can be prone to air locks for a number of reasons. Best of luck. Bill. PS: If it got there - sorry for the previous mail to your personal account - wrong button!!