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Wiring questions - installing new thermostat

Discussion in 'Plumbing and Central Heating' started by jespencer, 26 Dec 2012.

  1. jespencer

    jespencer

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    New Thermostat Honeywell (Homeexpert) THR870C

    Old thermostat Drayton RTS-1

    I have three wires poking out out my wall, appears Honeywell is a two wire unit.

    Wires are blue, brown and yellow+green.

    http://www.homexpertbyhoneywell.com/Documents/EN Manuals/THR870CUK-EN-d05.pdf

    I have the Brown going into A, the yellow+green into C and the blue taped off. The thermostat is calling for heat but the boiler is not responding.

    Any helpers out there? Thanks.
     
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  3. doitall

    doitall

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    The simple bit is the switching pair is A_B.

    But first you need to say where (No) the wires were connected in the old stat
     
  4. jespencer

    jespencer

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    My friend took off the old baseplate before we took a picture, but I am reasonably confident that

    Blue - neutral

    Brown - live

    yellow green - ground...

    Does this make sense?
     
  5. doitall

    doitall

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    There'll be a big bang if it isn't.

    Move the wire from C to B and keep the fingers crossed.
     
  6. mikely

    mikely

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    No it doesn't, because the RTS1 requires Live, neutral and switched live. See http://www.draytoncontrols.co.uk/WorkArea/DownloadAsset.aspx?id=10497
     
  7. jespencer

    jespencer

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    Have taken another look at the old rts one

    N - blue

    L - brown

    3 - "call" yellow / green.

    Assuming this is correct, for the new unit,


    A - Brown

    B - yellow + green?

    Thanks,
    J.
     
  8. doitall

    doitall

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    Yes as I said move the yellow/green from C to B. :rolleyes:

    And stick the blue in N.
     
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  9. RF Lighting

    RF Lighting

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    Sounds like you need an electrician to take a look at your wiring.

    green & yellow should NEVER be used for anything other than earth.

    Connecting an EARTH wire to a live terminal is going to end up with either a dead thermostat, or someone else who has the misfortune to work on this wiring being killed.
     
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  11. ericmark

    ericmark

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    Although likely Brown to A and Blue to B one should not really guess. If wired correct as I would expect there should have been a brown sleeve on the blue wire.

    I have come across many odd systems which do not follow the rules including using a green/yellow as a line wire and this was original wiring on a Persimmon Homes house which one would have thought would have been wired correct.

    So really only option is call an electrician to sort it out.
     
  12. mfarrow

    mfarrow

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    Why? Just over sleeve the green/yellow with brown, assuming the thermostat isn't installed in a metal back box and doesn't need an earth in its own right.
     
  13. dingodeano

    dingodeano

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    Green and yellow should NEVER be used as a live conductor.
     
  14. RF Lighting

    RF Lighting

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    That's nothing but a dangerous bodge.

    You really need to stop giving out electrical advice if you have no idea of safe working practices, regulations or the law which governs this sort of work.
     
  15. doitall

    doitall

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    The blue is a neutral Eric not a switch wire. :rolleyes:

    The OP has said where they were connected and the rest is simple.

    And I've seen 1000s that have been wired by so called sparkies that use the G/Y as a switch wire, not sleeved.
     
  16. doitall

    doitall

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    If the sparky knew his job he would test before he sticks his fingers in and starts playing.

    In an ideal world you are right they wouldn't use the earth wire, but there's as many that do as don't.

    If it's sleeved or taped red I don't see the problem, and in any case if you know what you are doing you will be able to relate to the numbers the wires are connected too.
     
  17. RF Lighting

    RF Lighting

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    You can't try and pass the buck like that. If you knew how to drive you wouldn't need a seatbelt or airbag in your car. What a ridiculous statement to make.

    The fact that you don't see the problem just shows you shouldn't be advising anything to do with electrical work.

    It's not about ideal world conditions it is the most basic of electrical safety principals.
     
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