Bleeding Radiators!!!

[BertieButton]

My fathers radiators are very hot and cold! I have got a key to bleed them, but don't know in which sequence - if any- I need to do them in! Of the 11 radiators in the house, some are very hot (too hot to touch!) when the system is on, some are warm and some are stone cold! This is an old house with an old system. Will bleeding them sort this out ? Or is the old man, in the old house with old radiators needing to be COMPLETELY overhauled? Any help or advice would be much appreciated before he dies of hypothermia!

[Postdog]

No sequence. Use the key on every one. If air comes out, let it, and when water comes out, shut. simple.

[gen2]

We had a radiator that stayed cold even though it had been bled. It turned out the valve had stuck. Screwing the valve down to 0 and back to 5 about half a dozen times got the water flowing again.

[ChuckFickens]

couple of points though

Bleed the rads with the heating turned off

if it's a pressurised system then you may have to top the system up after bleeding it, check and make sure you know how to do this before bleeding the rads.

[rov1200]

Whether it is right to do so I always bleed my radiators when the pump is operating. Then the pressure of the water expels the air in the radiator.

[BertieButton]

Thanks guys! Will give it a go and see what happens! However, if you hear a loud bang coming from a Northernly direction you'll know things have gone Tapas up!

[magicmerlin]

You should always bleed the radiators with heating off as the pump should normally suck the water through back to the boiler. Gravity will fill the radiators quick enough.

[ChuckFickens]

rov,

if you always bleed your rads with the heating on (i.e. the pump running) then that probably explains why you have to keep bleeding them.

bleeding rads with the heating running increases the chances of sucking air back into the system

[buildersmate]

If attempting to bleed one of the cold rads merely results in water starting to emerge (and no gas), this system does NOT need bleeding. Bleeding seems to be seen as the panacea for all ills to do with hot and cold rads, when by-and-large it is nothing to do with it. The system probably needs balancing. This means increasing or reducing the flow of water in some rads in relationship to the others. There's an explanation on how to do it here.
http://www.diydata.co...adiator_balancing.php

[BertieButton]

Thank-you so very much buildersmate! I think that you have answered my probelm and that I do indeed, need to balance the radiators, as bleeding them hasn't entirely worked ! Cheers! I owe you a pint.

[buildersmate]

It is worth the investment in a couple of little click-on thermometers - about £10 I would guess. Balancing isn't all that difficult, but it does take a heck of a time because you have to allow time for the temperatures in the various parts of the system to change aftetr an adjustment has been made.
The other issue that it is not always clear which rads are closest to the boiler (in terms of length of pipework) and which are farthest away. You will just have to experiment. When you start, make a note of how many turns (measured in quarter turns) each lockshield takes to open it up completely - that way you can always return it to where it was if you get into a complete mess.
Do not be surprised if the rad closest to the boiler is only a tiny bit open (maybe only one quarter turn from being competely shut) - if you are getting the necessary temperature drop across the rad, enough energy is being pumped into it and being given out into the room.

[Panic Button]

You can tell if a radiator needs bleeding if it is cold at the top but hot at the bottom.

[terence7556]

if it is cold at the bottom only and warm/hot at the top it may be sludged up with gunk/crap, especially on a downstairs rad.it will need to be cleaned by removing and washing out with a hose in the garden or the whole system needs a clean called a powerflush but this is an expensive option