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Boiler keeps turning itself off....??

Discussion in 'Plumbing and Central Heating' started by jonnie84, 15 Dec 2010.

  1. jonnie84

    jonnie84

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    Hi all my central heating continually turns itself off and wont restart for 10 15 mins
    Im trying to find out if this is an elctrical or plumbing problem??

    The boiler is a Vaillant ecotec plus 612 condensing, when it goes off ,,

    the code S.30 appears which states "room thermostat 3/4 no heating demand".

    The room stat brand new and is a Horstmann hrt3.

    Any ideas what the problem could be ??

    Many thanks in advance
    Jon
     
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  3. nogoodatfaultfinding

    nogoodatfaultfinding

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    you any good at electrics???
     
  4. jonnie84

    jonnie84

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    I can test things ..but generally leave electrics to the pros!
     
  5. nogoodatfaultfinding

    nogoodatfaultfinding

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    remove the room stat from your PCB and put the/ A link back in its place then tell us whats going on please
     
  6. jonnie84

    jonnie84

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    Right I've referred to the instructions of the boiler , removed wire from 4 linked 3 &4 together and the boiler now comes on fine.

    Does this mean i have dodgy room stat??
     
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  8. flounder

    flounder

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    Does it start without you re-starting it ?
    When the boiler has switched off can you hear the circulation pump running ?
    A stuck pump will cause this. The heat in the boiler exchanger will linger for a long time if the energy is not removed by the pump. Say 10-15 mins
    A massive air lock can stop water circulation.
    Is it cycling due to the hot water in the boiler not being dissipated in the radiator circuit therefore boiler stat over rules
    Note : if the boiler is supplying more hot water that the radiators can dissipate it switches off, but the pump must keep running.
    Are all the radiator valves fully open, including the lock shields ?
    Are any radiators getting hot. Some will even if the pump has stalled by gravity feed.
    When it is on, does the room stat, when clicked to a low temperature switch the boiler off ?

    Just a few questions off the top of my header tank

    Regards flounder
     
  9. nogoodatfaultfinding

    nogoodatfaultfinding

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  10. nogoodatfaultfinding

    nogoodatfaultfinding

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    Yeah mate its a dodgy stat or a dodgy wired stat either way thats all your fault was hope this helped
     
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  11. jonnie84

    jonnie84

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    Brilliant thanks so much really helped
     
  12. jonnie84

    jonnie84

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    Before i go get a new stat can anyone tell me if this one is wired correctly??

    Red is going to 1 ....Line
    Black is going to 3....Load (Heat)
    Green is going to 4.....N

    having just traced the cable back to a Honeywell "junction box" the other end of the green cable is with all the earths?? but if i disconnect it from the stat the led light goes out!
    Many thanks
    Jon
     
  13. DIYnot Local

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