Wiring wireless room stat into Combi boiler

Discussion in 'Electrics UK' started by thomo2710, 14 Dec 2010.

  1. thomo2710

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    Hi all,

    Could somebody please help me understand the following diagrams on wiring my new room stat into my boiler.

    Boiler - Vaillant Turbomax Pro 24e
    Stat - Honeywell CMT927 Wireless

    Boiler wiring:
    Page 17 of the following PDF link
    http://neighbourconstructions.co.uk/...stallation.pdf

    Stat wiring:
    Page 7 of the following PDF link
    http://www.plumbnation.co.uk/site/ho...cification.pdf

    Currently the boiler has a loop wire in pin 3 + 4 for the plug in vaillant timer. I know i havre to take this out.

    T1 and T2 are pin 3 and 4? Assuming looking at page 18 of the vaillant PDF
    I dont know what that 10a fuse is for and where the diagram goes off too towards the left.

    Boiler is currently hooked up to the mains supply via a fused spur.

    The reciever unit is powered off a switched live.

    My friend is confident he can do it as he is fairly competant with doing electrics but i want to clarify 100% what goes where first as he doesnt want to go ahead for deffo and turn the boiler back on with a bang before we are 100% certain what goes where.

    Thanks in advance.
     
  2. thomo2710

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    ok so having another look over it am i anywhere close?

    2 cables

    1st cable - core 1 in pin 3 (T1) to A and core 2 in pin 4 (T2) to B
    2nd cable - core 1 piggybacked into the L on the boiler board to L and core 2 piggybacked into N on the boiler board to N

    The 10a fuse is what should be in the fused spur socket?

    How close am I?
     
  3. holmslaw

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  4. thomo2710

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  5. holmslaw

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  6. thomo2710

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    Thanks man, ill check what fuse is in the spur already at lunch time.

    But apart from that am i there with what i put in post 2?
     
  7. holmslaw

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  8. thomo2710

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    Diagram B on Page 7 of the Honeywell manual.

    A on stat to T1 (3 on boiler)
    B on stat to T2 (4 on boiler)
     
  9. holmslaw

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  10. thomo2710

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    Re: Help wiring Honeywell CMT927 roomstat into Combi boiler
    Hey me again

    Sorry to be a pain..... I'm doing this tonight and I want to get it 200% right as it's not exactly the weather to be without a boiler.

    N L L on the relay box.

    Boiler is run off a switched spur.

    N on relay box - do I tap into the N on the boiler pcb and run the other end into the N bank on relay box.

    Middle L - tap into L on spur socket to Middle L on relay box?

    Right side L - single core cable from that straight to L on boiler pcb?

    Picture on install only shows 2 wires - 1 in N and other in rightbside L

    Thanks in advance
     
  11. londonboy

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    Ignore the middle L terminal on the receiver.

    It needs a Live and Neutral, you can get this from the spur, or from the PCB, makes no odds.
     
  12. Marco1976

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    sorry to hijack the post but i have a similar problem.

    Does the Live in the relay box need to be connected to another terminal within the receiver?
     
  13. thomo2710

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    I got mine working with:

    N in relay box to N on fused spur socket
    Right hand side L in relay to L on fused spur socket

    Left middle L in relay box empty.

    Also use 1.5mm cable as the relay box terminals will not accept 2.5mm cable as I found out!!
     
  14. londonboy

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    You did well getting 1.5mm in there, I usually use 0.75mm :LOL:
     

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