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Discuss Heating and hot water keeps turning on and off please help in the Central Heating Forum area at

  1. Mrme

    Mrme New Member

    Having problems, heating and hot water turn on then off then on over and over.
    I am a totally unqualified but have a bit of sense.
    When it goes off our "honey we'll st9400c" goes completely blank, then seconds later it turns on again, over and over.
    I have noticed a red contraption which I think is a pump or some kind of power thingy. It is an "alpha2 l", this keeps turning off the it lights up with power and has full bars decreasing to zero, then sometimes it stays on for 20 seconds, sometimes 5 seconds, then turns off - this makes the honey well contraption above, turn off. Then it repeats over and over.
    Can anyone help?
    Recently had a boiler service and they said my boiler was in perfect shape.

    View attachment 15389376650982563180701270697108.jpg
  2. AMGasServices

    AMGasServices GSR

    It sounds like you are having issues with your programmer.

    The red thing you referred to is your pump.

    Are you any good with basic electrics I could tell you a method to link it out ?
  3. Mrme

    Mrme New Member

  4. AMGasServices

    AMGasServices GSR

    Isolate the power to the whole system,

    Undo the screws below the programmer (Honeywell St... )

    Take a picture of the back plate and the wiring guide upload it here.

    You will need two short pieces of wire to loop the connections.

    Or alternatively you could get yourself a new programmer like for like and install it.
  5. doitmyself

    doitmyself Well-Known Member

    It could also be the Alpha 2L pump causing the problem. They have been known to cause voltage spikes. Grundfos will provide a special power lead to solve the problem.
  6. Mrme

    Mrme New Member

    Hi I bought a new unit and swapped the faces, all works perfectly now, no wiring required. Phew. Thanks for all of the advice everyone.
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