Banging radiators

Discussion in 'Plumbing and Central Heating' started by chezzer0361, 7 May 2007.

  1. chezzer0361

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    3 of the radiators in the house keep banging when they are starting to cool down.

    Live in a 3 bed terrace so I don't think I need to go into detail but the kitchen one and the bedroom radiators all bang, the combi boiler is under the stairs by the way.

    It is driving me insain, tried bleeding them, and as soon as you turn the nut the water comes out so no air lock................

    So why do they bang so much, it usually starts after they have been one for about an hour and goes on till you turn the thermostat down, then again when they are cooling down to go off.

    Any ideas would be very much appreciated, before I rip the bloody things off the wall and get economy 7 instead................. :mad:
     
  2. gas4you

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    Have you got bi-directional trv's fitted? You can check by looking at them and seeing if they have 2 arrows on them.

    If onl 1 arrow on them they may be installed the wrong way round.
     
  3. Richsoft

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    What make of combi is it and what does the pressure gauge say on the boiler?
     
  4. chezzer0361

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    there is just one arrow on the TVR thing

    It is a Baxi Combi Boiler 105HE and the pressure gauge is just below 1
     
  5. gas4you

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    when the rads are cold, turn the heating on and the pipes that get hot first will be the flow. Does the arrow correspond to the direction of the hot water flow through the rads?
     
  6. chezzer0361

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    sorry don't understand, there is one arrow on the tvr and numbers 1 to 5. On the pipe things there is a white cap with a arrow saying forward and back and + and -.........................

    Not used to central heating had economy 7 for 10 years, now got central heating and haven't got a clue how to work it................lol

    I expected to ( like my mums house ) if it was cold go to the hall and turn the thermostat up, done, but my new system isn't like that even................so I apologize if I sound blonde...................... :rolleyes:
     
  7. werewolf

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    When a rad starts banging go turn the trv upto the next number or 2

    .Does the banging stop?
    Yes?
    Ergo, faulty trv or most prob fitted at wrong end of rad.
     
  8. chezzer0361

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    yes the banging stops until the radiator heats up again, then banging starts again when it is cooling down again...................the one in the kitchen is the worst it bangs like a jack hammer, well it sort of throbs. It is worst when it is due to go off, i.e. the heating goes off at 9am so from about 8.30 the banging starts.

    So she I get new TVR or change them to the other end of the radiator, is there a rule on which end they all seem to be, as you look at the radiator they are all on the right hand side........................
     
  9. gas4you

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    Right hand side is usual but not mandatory. You can remove valve and just turn it around on the same end if you have room for the head to poke out sideways ;)
     
  10. somnerd13

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    We had this, and had everything suggested, air in the system, pressure to high, pressure to low, etc etc. One day I went to sort it on my own and I found the radiator that was causing it - turned out it was because the control knob for the TRV had come very lose. Tighened it up and it hasn't happened since. The banging was absolutely unbelieveably loud and at times vibrated to other radiators on the other side of a very big house!
     
  11. chezzer0361

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    will try that, I will try anything, it was banging away for about 1 hour this morning, i just could not be bothered getting out of bed, when I did the radiators where cold upstairs and warm downstairs...........

    I think I need to get someone out to it, before I rip the thing off the wall.

    Also the pressure has dropped to just below 1, it is usually between 1.5 and 2, does it drop in Summer ?????? do I need to get it back up to 1.5 ???
     
  12. gas4you

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    If pressure is dropping could ponit to another fault in boiler, or do you mean it is 1Bar cold and 1.5Bar when rads hot. If so this is normal ;)
     
  13. chezzer0361

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    it is at just under 1 bar on the pressure gauge all the time. In winter it was at 1.5..................

    We turned off the radiator in the kitchen last night because it was so bad and noisey and this morning the radiator in the lounge which is usualy luke warm was really hot ???? So I think the problem lies with the kitchen one this is parellel to the boiler.

    The towel rail in the bathroom get's so hot it nearly burns your hand, this is locted directly above the boiler ???????
     
  14. chezzer0361

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    gas4 you.....................


    turned off the radiator in the kitchen and no banging, so stupid question but, this is obviously where the problem lies, it doesnt need bleeding, so what else would you suggest I do............


    Many Thanks, and I will not ask any more questions after this one................... :LOL:
     
  15. gas4you

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    Replace kitchen trv with new bi-directional one ;)
     

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