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Upgrade to Nest Thermostat E from Honeywell R6660D

Discussion in 'Plumbing and Central Heating' started by Sebastião Schumaher, 18 Jan 2020.

  1. Sebastião Schumaher

    Sebastião Schumaher

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    Hello guys, I am trying to figured out the wiring on my current Honeywell Receiver which works fine with my wireless Honeywell CM927.

    I am confused with the current wiring of my receiver - please see pictures which I will attach:

    current wiring:

    N blue cable (I guess neutral)
    L brown cable (I guess live)
    L brown cable (this is where I get confused as this is a small brown cable connecting A to L like a loop cable)

    A small brown cable coming from L as above
    B green cable (I guess open wire?)
    C empty
    D empty
    E empty

    on my new nest heat link I need to identify the common and open wires from my current setup so I can carry on.

    any help would be appreciated.

    regards,
    Seb.
     

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  3. Sebastião Schumaher

    Sebastião Schumaher

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    One more picture if it helps
     

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  4. ianmcd

    ianmcd

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    Couldnt be simpler but never go by wire colours on a heating system

    honeywell Nest

    N to N
    L to L
    Link L to 2
    C to 3
     
  5. Sebastião Schumaher

    Sebastião Schumaher

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    Thanks mate. What do you mean C to 3? On my current setup C is not connected to anything?
     
  6. Sebastião Schumaher

    Sebastião Schumaher

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    If anyone can just confirm what’s the common and open wire on my current system that would be great. I want to make sure I understand current wiring to proceed with the next steps. Thank YOU in advance
     
  7. EFLImpudence

    EFLImpudence

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    2 is Com
    3 is NO (normally open)

    Typo should be B to 3

    upload_2020-1-18_13-7-48.png
     
  8. D_Hailsham

    D_Hailsham

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    The two L terminals on the Honeywell reciever are linked together internally. The loop from L2 to A means that terminal A always has 240Vac on it. When the switch in the receiver closes terminal B (switched live) provides 240Vac to turn the boiler on.

    Terminal C is used for cooling systems.
     
  9. Sebastião Schumaher

    Sebastião Schumaher

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    Thank you so much for all the answers, things are starting to get clear in my diagram mind :)

    As per what D_Halisham said I will then use the brown cable currently connected to L1 as my common wire and the cable connected to B my open wire, therefore the small brown cable connecting L2 to A can be just removed.

    I tried to draw what I will be doing just to confirm if anyone can please confirm it that would be great. I don’t want to try anything before I am 100% as wife already threatened me with a divorce depending on the outcome....



    Read more: https://www.diynot.com/diy/threads/...e-from-honeywell-r6660d.537310/#ixzz6BOCMxxGg
     
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  11. Sebastião Schumaher

    Sebastião Schumaher

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    Drawing of what to do next with wires
     

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  12. EFLImpudence

    EFLImpudence

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    No, you're not paying attention.

    N to N
    L to L
    Link L to 2
    C B to 3
     
  13. ianmcd

    ianmcd

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    yes it is
     

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  14. ianmcd

    ianmcd

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    you have got them wrong that is B&C not A&B
     
  15. ianmcd

    ianmcd

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    sometimes wonder why we bother mate the B that is actually C
     
  16. EFLImpudence

    EFLImpudence

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    No, it isn't. Either way C is normally closed.

    upload_2020-1-18_15-3-25.png
     
  17. Sebastião Schumaher

    Sebastião Schumaher

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    EFLImpudence
    thanks a lot for all the spot on info however do you mind clarifying when you said:

    N to N
    L to L
    Link L to 2
    € B to 3


    my new Nest Thermostat only requires two cables (Common and Open) therefore N and L1 won’t be used from what I understood - I will use the terminal blocks to isolate them.

    Link L to 2 means I will connect L to Common socket on nest?


    € B to 3 means I will connect B to NO socket on nest?


    I didn’t understand what numbers 2 and 3 meant on your earlier post. I will post a picture of how Nest thermostat sockets are arranged.






    Read more: https://www.diynot.com/diy/threads/...e-from-honeywell-r6660d.537310/#ixzz6BOY4TEru
     

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