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Honeywell Y plan diverter valve 'BANG'

Discussion in 'Plumbing and Central Heating' started by stred, 7 Nov 2011.

  1. stred

    stred

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    Hi all

    I am wondering if anyone can help me please regarding the 'Honeywell Y plan diverter valve'.

    When my CH is on and the HW switches on i get a very load bang, and it seems its coming from the honeywell valve. (like someone heating the pipe with a hard object) its enough to make you jump!
    and its not nice when it bangs at 5am!!

    But when the CH is off and HW switches on there is no bang at all. is this a fault? will it cause any damage? why does it only do this when CH is on?


    One more thing that i have noticed is the Siemens landis & staefa room thermostat little orange light comes on when the CH is on, when the thermostat cuts off is the light supposed to switch off? because it only goes dim and only switches off completely after awhile or when the HW comes on.

    Be very greatful if anyone can help.

    Regards

    Lee
     
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  3. Boilerman2

    Boilerman2

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    Sounds like the valve needs a Service kit fitting, the valve seat is a rubber ball which can become softened this often leads to the valve Banging when it changes ports

    as for the thermostat - sometimes a small back feed can make a neon or led glow slightly so unless the thermostat is not working I personally would not worry about it! ;)
     
  4. stred

    stred

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    Thanks Boilerman2 for your swift reply, can this service kit be installed by myself and is it easy? any system drain needed?

    I took the cover off the valve and turned the room thermostat up and see the spring move, the after a while i turned the thermostate down a bit so the neon is just a faint glow, i then switch on the HW via the program and the spring moves again back and forth a little bit thats when you get that loud 'clonk' the valve is only about 11 months old as we had the previous one replaced when the water wouldnt heat up the valve used to just click.

    Thanks again for your help.
     
  5. stred

    stred

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    Thanks Boilerman2 for your swift reply, can this service kit be installed by myself and is it easy? any system drain needed?
     
  6. Agile

    Agile

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    If the valve is only 11 months old then I would be surprised if it has become noisy so soon.

    There could be another cause!

    The system needs to be drained in the vicinity of the motor valve as otherwise water comes out when the plate is removed.

    Tony
     
  7. stred

    stred

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    Its only a problem when the CH has been on, when when the CH goes off the orange light on the thermostat doesn't completley go off it has a faint glow, its only then when the HT comes on the valve bangs and then the orange light on the thermostat goes off. If the CH isn't on the valve doesn't bang at all when the HT comes on.
     
  8. misterdubya

    misterdubya

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    As its a 3 port valve, it will generally only bang when the hot water (only) is in demand after a period of central heating use.

    This is because the valve will stay in the central heating position after the heating switches off - the 'y' plans are wired that way.

    When the water comes on, the power to the valve is cut, and the ball bangs when the spring pulls it back.
     
  9. stred

    stred

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    So is this suppose to bang then or is it a fault? And why does it only do it when the light is dim on the stat? Because when th CH is on and the light is bright it never bangs, its only when the stat reachers temp and then the light goes dim not fully off it bangs and for some reason as soon as it bangs the dim light goes out.
     
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  11. stred

    stred

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    So is this suppose to bang then or is it a fault? And why does it only do it when the light is dim on the stat? Because when th CH is on and the light is bright it never bangs, its only when the stat reachers temp and then the light goes dim not fully off it bangs and for some reason as soon as it bangs the dim light goes out.
     
  12. matt1e

    matt1e

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    because as long as the central heating is on the valve will always be open so it wont bang
    try selecting hotwater off at the progammer, turn on central heating only then turn the room stat on and off, this time there should be no banging as the valve stays open in this situation
    is the pipe work around the valve secure?
    though I'm sure I read a recent post stating that some of the honeywell ones had faulty springs
     
  13. stred

    stred

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    I have tried this and there is no bang, but when i turn the room stat on and off the little neon light comes on then it doesnt go off when i turn the stat down to zero, it just dims with a faint glow. However when i switch the hotwater on at the programmer i hear the valve operate and then the bang, thats when the dim neon light goes off on the room stst.

    Any ideas?

    Thanks
     
  14. matt1e

    matt1e

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    Hi first of all stop worrying about the little neon as it has no baring on your problem whatsoever its just getting a small backfeed from the valve due to the valves internal circuitry while the valve is in anything other than the HW position thats all

    as I asked earlier is the pipe work around the valve soildly fixed?
    another thought is that the valve and pump may have been fitted on the return, take a look at the pump body, there will be an arrow stamped on it which should be pointing towards the valve not away from it

    Matt
     
  15. stred

    stred

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    Hi Yes the pipe work seems to be fixed solidly, no movement or knocking on any other pipes.

    I have no idea where the pump is? lol there is no sign of it in the airing cupboard. i can take a pic of the pipe work in cupboard showing valve, but no pump.
     
  16. matt1e

    matt1e

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    Photos are always useful!
    the pump may be integral to the boiler, what make/model is it?
     
  17. stred

    stred

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    It is a Potterton Performa System HE and your right it has a circulation pump inside.

    Here are the photos of the valve set up.
     
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