Central heating not coming on

Discussion in 'Plumbing and Central Heating' started by strautman, 1 Oct 2014.

  1. strautman

    strautman

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    Ok I have looked extensevly on here and have found some good answers to my questions however none of them work. I have replaced the thermostat as I needed a new one anyway, I have also replaced just the box to the three way port. Hot water comes on perfectly with the timer but central heating will not come on at all. programmer light comes on for central heating but nothing. can not here the motor making any noise at all. I have checked the wiring with a multimeter which I get 240 with one end to live other touching another wire until it comes to the grey wire and to get a 240 reading I have to put the red terminal on the neutral.
     
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  3. Ihavenojob

    Ihavenojob

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    The demand & common are the wrong way round on the room stat,not a problem on some but an electronic one with a relay wont work.
     
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  4. strautman

    strautman

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    Thanks I have changed it however it still does not come on.
     
  5. Ihavenojob

    Ihavenojob

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    Just looked again & the cyl stat is wrong, terminal 1 is not a neutral,you will have common (from HW on clock) normally closed( or break on rise is the demand) & normally open (make on rise which goes to HW off on clock)Look online for a honeywell y plan wiring diagram,theres one in the FAQ's at the top of the page.
     
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  6. 45yearsagasman

    45yearsagasman

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    This may help.
     
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  7. strautman

    strautman

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    Thanks for the responses. I have updated the drawing and have made changes but still nothing. If I turn hot water on boiler and pump come on. If I turn CH on no motor noises. if just CH nothing at all motor not moving, pump or boiler not coming on.
     
  8. picasso

    picasso

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    If your sure the wiring is correct make sure you havent screwed down on to the insulation on one of the wires, its easily done.
     
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  9. CombustionGuy

    CombustionGuy

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    Did you check the 3 port wasn't stuck ?
     
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  11. strautman

    strautman

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    if I put it to manual the rads get hot. with the box off the three port i can turn it by hand roughly between an eighth and a quarter turn. noticed that the lever on the box stops halfway up.
     
  12. strautman

    strautman

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    Have checked all the wiring and have not clamped down on any insulation. Thanks for the idea picasso
     
  13. APHSLTD

    APHSLTD

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    If you're getting 240 from a permanent live to white (sometimes white&brown) on your mid position valve then you have no power on the white wire.

    The reason you get 0 between permanent live and grey is you have 240V on both wires hence no potential difference.

    Check white wire to neutral with CH demand if no voltage check your timer & stat again.
     
  14. D_Hailsham

    D_Hailsham

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    Connect the valve's White and Grey wires to terminal 1. The boiler should light and CH come on.

    If it doesn't, the valve actuator is faulty.

    Is the spindle easy to turn when the actuator is removed?
     
  15. strautman

    strautman

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    Thanks Hailsham I hooked the white and grey to terminal 1 and when I turned the central heating on it came on. So what could be wrong if it is not the 3 way?
     
  16. picasso

    picasso

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    Connecting the cylinder stat to neutral has probably fubared the 3 port.
     
  17. strautman

    strautman

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    if it was fubard then I thought it would not come on when white and grey was connected to live.
     
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