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Radiator Cold at the Bottom - Full of gunk?

Discussion in 'Plumbing and Central Heating' started by edwardlewis, 20 Dec 2011.

  1. edwardlewis

    edwardlewis

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    I have got a radiator that is really cold at the bottom. I have tried switching the others off and turning down the valves on others etc but it still isnt getting hot all of the way down. The pipe on the left is only slightly warm too.

    From all of the things I have seen online I think it might be full of sludge.

    I have just run a load of water out through the bottom valve and that is what came out.. is it normal!?

    [​IMG]

    Can I just keep running water out of it? Will that flush out all of the gunk?
     
  2. edwardlewis

    edwardlewis

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    I think the colour of the water in the pic might be made darker because its on the dark floor..

    I just ran a load more water out.. I noticed that when the water is running out of the bottom valve, the radiator does start to warm up slightly... I'm not sure if that is significant or not?!
     
  3. ChrisR

    ChrisR

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    Not good at all.
    Turn the other radiator valve off so you can drain via this drain cock with a btof luck - depends on system....

    Anyway remove the radiator and take it into the garden, and flush it though with the garden hose, half-filling and inverting several times until the water comes out CLEAN!.

    Much easier with two people, but even a woman can be a help ;)

    That will probably fix this single rad but your whole system needs flushing.

    There's lots on the forum but if you connect one hose to one rad pipe (garden tap fittings are the same thread) and another to the other, you can flush the system quickly,
    though really you need to cut off the supply to the header tank empty and clean it, connect the vent to the feed pipe...

    If you con't do that lofty stuff it'll still work fairly well, but your loft tank may overflow - so check it's working ok.

    Doing the job "propely" is well covered , see Power Flushing.
     
  4. JohnD

    JohnD

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    I'm guessing you have an open-vented system with a feed and expansion tank in the loft.

    If you are able to drain the system and hose out the rads, that's great.

    However you can add a sediment-loosening chemical such as Sentinel X400, and run the system as normal for 4 weeks. That will help get the sludge circulating. You will know it is starting to work when the water goes jet black with loosened sediment (try a bleed valve). X400 will cost you about £15 for a litre. Other faster-acting chemicals are available but some of them are aggressive and you will have to clean, flush, rinse and refill in a day.

    Tie up the ball float and bale out all the mud from the F&E tank first, and drain out a bucket or two of water before you add the chemical, so it is drawn down when refilling.

    Can you do basic plumbing? Can you afford an extra £100 or so? There is more you can do.
     
  5. edwardlewis

    edwardlewis

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    Cool.. Thanks for the info..

    I live in a flat, I've got a combi boiler so there is no loft or expansion tank - does that make things easier or more difficult?

    Should the water out of the radiator be clear?
     
  6. JohnD

    JohnD

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    if you have no tank, then opening the drain cock should let a modest amount of water out, after which the pressure will drop and it will stop.

    however putting a hosepipe on the drain cock, and letting it go down the WC while you turn the filling valves on, gives an easy way to wash it out (preferably only one radiator on at a time). Put a jubilee clip on the hose and have someone watch ity, the black stain is very severe and impossible to fully clean out of carpets.

    but it is more difficult to get the chemical in as you have to squirt it through a radiator bleed valve hole instead of pouring it into a tank. You can buy cartidges of concentrated chemical that fit a caulking gun. It is easier when the rad is despressurised and drained.

    If yours is a pressurised system and has never been open vented, it is less common for it to be badly sludged, unless it used previously to be open and was not properly cleaned on conversion, or it has been leaking and frequently topped up, or the filling valve was accidentally left open. It should have been filled, after cleaning, with a corrosion-inhibiting chemical such as Sentinel X100 or the Fernox equivalent. I don't think it was.

    how do you feel about that basic plumbing and an extra £100?
     
  7. edwardlewis

    edwardlewis

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    Thanks for the info.. it all helps :)

    Whats the extra plumbing and £100? Is it pyramid selling?!
     
  8. JohnD

    JohnD

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    no, it's fitting a filter which will trap the particles out of the circulating water and prevent future accumulations and blockages. As you already have sludge it will be best if you fit that before using a sludge-loosening chemical, so it is pumped round and passes through the filter.

    Sentinel, Fernox and Magnaclean all make them. The plastic Magnaclean is spectacular at collecting black sludge but it commonly suffers from drips and leaks after a few years. The others, especially the brass Spirovent, seem to be better made. The filters mostly cost around £100, give or take a bit (Screwfix has the Sentinel on special offer this week, but is out of stock). They are pretty easy to fit but you need to partially drain and cut a pipe to do it. It is easy to pour chemicals down the cut pipe with a funnel while you are working, and they all (AFAIK) have a valve you can squirt chemicals into later.
     
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  10. edwardlewis

    edwardlewis

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    I took the radiator off a few days ago and washed it out... it was a looong job!

    When I went to the plumb centre to buy a radiator key I spoke to a plumber in there and he serviced my boiler on Friday.. he's coming back next week to fit one of the filter things on the pipe going back to the boiler and putting some chemicals in there to shift the rest of the gunk.

    cant wait to get playing with the magnet thing.. they look amazing!
     
  11. edwardlewis

    edwardlewis

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    It's all done.. looking forward to cracking it open later to see whats inside!

    Thanks for the help and advice from everyone.

    [​IMG]
     
  12. JohnD

    JohnD

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    you have got isolating valves on that Magnaclean, haven't you?

    I can't see them in your pic.
     
  13. dormermike

    dormermike

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  14. ChrisR

    ChrisR

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    I can see one!
     
  15. edwardlewis

    edwardlewis

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    yeah, the valves are round the back, one is just sticking out on the pic
     
  16. adamsheating

    adamsheating

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    They are behind, you can see one poking it's little head out! Would like to see a mag fitted without the valves provided in the box, it would be more work!
     
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