Radiator problem

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balance the system, then change your pump, then replace the radiator valves,then repipe the whole system and lastly replace the rads.
 
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Actually, all you need to do is bleed the radiator concerned with a rag handy to catch the water. Once you've doen this, you may need to top the pressure back up - so keep an eye on the pressure gauge on your boiler.

The radiator is hot at the top and cold at the bottom.

This is not caused by air in the radiator.
 
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Completely turn off all other rads (not just the TRV'S) then check this one, It should get hot instantly if the only problem is a balance is required.
If it does then just crack open the others again one at a time till all are hot.
The problem tends to say that the heat is getting there but not returning so as stated by someone else DO NOT try bleeding it even with a bucket as you will be their forever and a day.
 
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Completely turn off all other rads (not just the TRV'S) then check this one, It should get hot instantly if the only problem is a balance is required.
If it does then just crack open the others again one at a time till all are hot.

This is generally sound advice, however if a TRV is working properly it will completely stop the flow through the radiator when turned right down, provided the room is warmer than 15 degrees or so. If a balancing problem is confirmed then the lockshield valves should be adjusted to improve the balance.

It's worth bearing in mind that if the hot water circuit is operating it will take water away from the radiators unless a lockshield valve is fitted and properly adjusted.

There are two main causes of a rad being hot at the top and cold at the bottom, these being:

- insufficient flow of heated water through radiator

- sludge deposits in bottom of the radiator.
 
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hello folks can i add my problems to this post.
i have the same problem with my system with almost all my rads not being very hot at the bottom.
the main problem is the living room rad cold at the bottom and very luke warm at the top.
i have taken of all the rads downstairs and flushed them to clear the sludge( and there was some)
these then all ran clear.
so after doing this to the living room one believe it or not it made it worse????
i have messed about trying to balance the rads the best i can but again no good help please?
its really doing my head in now with this very cold weather.
is there any advice please or do i need a plumber to sort my problem out?
i have a worcester combi boiler and 8 rads if that helps.
thanks
 
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To willy6215

Strictly speaking you should post a new topic rather than reply to an existing thread with a new problem. However it's on-topic so I don't suppose it will cause any harm.

Have you flushed only the radiators, or the pipework as well?

Have you tried a second flush of the problem rad?

What chemicals / inhibitor have you added to the system water?
 
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hello sorry.
when i flushedthe rads i checked the flow to the rads and both flow and return had a good jet of water, even the return of the problem rad?
when the system is running the return on he problem rad is cold?
no chemicals yet any ideas which ones are good?
 
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I would suggest you do this:

  • Buy a bottle of Sentinel X400 sludge remover, and a bottle of X100 corrosion inhibitor.

    Add the X400 to your system water and run the heating as normal for a month.

    Drain the system .

    Remove each radiator in turn and flush with a garden hose, or whatever method takes your fancy.

    Refit the radiators and refill the system. Run the heating for an hour or two.

    Drain once more before refilling again. Add the X100 as you refill.

    Then deal with any airlocks and balance the system.

If you've left the system with no inhibitor in, the amount of sludge will increase by the day (no kidding). The sludge comes from your radiators corroding from the inside, they can fail eventually so it's important to sort this out before it becomes a much more expensive job.
 
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thanks for your reply.
i have no idea how to drain the system?
forgot to say before the pipes under the floorboards in the hallway not far from dodgy rad are red hot to bot flow and return?
i think i will need someone to do this for me i have no time and i am not to familiar with rads and heating systems.
how much do you think i t would cost to do the work you state?
cheers
 
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Thanks to you all for your help. i Will try ballancing the set up. it had been completely drained for a while.

As for for you Gavinda YOUR SCHOOL REPORT READS " must try harder" the others did better with the same info.
 
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thanks for your reply.
i have no idea how to drain the system?
...
i think i will need someone to do this for me i have no time and i am not to familiar with rads and heating systems.

how much do you think i t would cost to do the work you state?
cheers

This should help: http://www.diynot.com/wiki/plumbing:faq

As for the cost, I have no idea. Probably the best thing to do is to ask some local heating engineers to give you estimates. They may recommend a different procedure such as a power flush - the way I described is more suited to DIYers.
 

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