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HELP! replacing a thermostat

Discussion in 'Electrics UK' started by scottishpete, 7 Sep 2013.

  1. scottishpete

    scottishpete

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    Hi. Desperately needing help fitting a room thermostat. I am trying to replace my potterton prt2 with a horstman centaurstat 7. I followed a previous thread to match my live wires from one to the other and put the neutrals into plastic ends.

    But when i put the power back on and upped the temperature my boiler never kicked in. In fact my boiler has no power to it at all.

    So i switched back to the old thermostat in the meantime but now thats not working with the same wiring and again no power to boiler.

    Any suggestions for.correct wiring and how to restore boiler power?
     
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  3. EFLImpudence

    EFLImpudence

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    How many neutrals do you have?
    If more than one - are you sure?
     
  4. scottishpete

    scottishpete

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    Previous wiring was com, h, tl and n. I matched TL with 1 (L) line, h with 2 (load heat), nothing to 3 (load cool), n to 4 (parking) and capped off com from my old thermostat.

    Have i wired incorrectly? Why would my boiler not work now tho when i rewired to original?
     
  5. scottishpete

    scottishpete

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    No power to boiler. Desperatly needing help on this one please
     
  6. EFLImpudence

    EFLImpudence

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    Let's start with the Potterton

    TL is Live - power to thermostat,
    N is Neutral
    H is Call for heat - switched signal to boiler
    Com is supply for H

    Com - If you have no other supply from the boiler then Com should be linked to TL.

    Have you for gotten the link?

    In effect TL is connected to H for the boiler to work.
     
  7. mikely

    mikely

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  8. scottishpete

    scottishpete

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    Got that link from seperate wires. Ill try and load a pic
     
  9. EFLImpudence

    EFLImpudence

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    Have you blown a fuse somewhere?

    In a switch near the boiler?
     
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  11. scottishpete

    scottishpete

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    How would i know or check? All other power seems to be fine
     
  12. scottishpete

    scottishpete

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  13. scottishpete

    scottishpete

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  14. EFLImpudence

    EFLImpudence

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    Oh dear.

    All you have to do is with the left hand pair of Brown and Blue.

    Brown to 1
    Blue to 2

    Right hand pair of Brown and Blue - NOT required.

    Brown in a separate piece of connector block and position safely out of the way.
    Blue to Park terminal.

    I fear, hopefully, you may have blown a fuse in the boiler but more substantial damage could have been done.
     
  15. EFLImpudence

    EFLImpudence

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    To confirm

    The picture is how the thermostat was originally wired - yes?
     
  16. scottishpete

    scottishpete

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    Pic was the original wiring. Ive just replicated it with no power. Also think the fuse in boiler has gone but not sure why or how to check?
     
  17. EFLImpudence

    EFLImpudence

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    Well, access is needed to the innards.
     
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