Changing Honeywell cm907 to hive thermostat

Discussion in 'Plumbers' Talk' started by stephen smith, Oct 21, 2016.

  1. stephen smith

    stephen smith New Member

    Hi folks

    I'm about to change my Honeywell cm907 thermostat to a hive heating thermostat,I have a Worcester combi boiler.
    In the Honeywell receiver beside the boiler,there live and neutral which I'm fine with,there are also two other wires,one goes into "A" and one into "B" which connections in the in the hive receiver do I connect these two....it says 4 is unused so that leaves 1,2 and 3

    Any help would be appreciated
     
  2. Jitender

    Jitender Well-Known Member

    CM907 is a programmable thermostat and only has 3 terminals A, B and C.

    A = Live supply

    B = Live Return (switched)

    there is no neutral?
     
  3. stephen smith

    stephen smith New Member

    Thanks for replying
    Looking in the receiver it has,a neutral and live connection which I'm assuming is permanent then a block marked ABC with wires in A and B.
    I need to know which terminals in the hive receiver do existing A and B go to

    Thanks
     
  4. Jitender

    Jitender Well-Known Member

    Is this the BDR91 receiver? so could be a wireless stat? Honeywell CM921/CM927 stat?
     
  5. stephen smith

    stephen smith New Member

    Yeah sorry I should have said that,it is BDR91,just need to figure out the A and B connection from it to the corresponding on the hive
    Thanks again for the help
     
  6. Jitender

    Jitender Well-Known Member

    This is what it is likely wired as at present. Link from L to A


    upload_2016-10-21_19-56-19.jpeg
     
  7. Glad its Friday

    Glad its Friday Active Member

    Got 2 combi's going there Jitender.
    But good diagram :)
     
  8. Jitender

    Jitender Well-Known Member

    Not wired a hive before, but have done a nest.

    This is for the WB :D

    upload_2016-10-21_20-21-16.jpeg
     
  9. Glad its Friday

    Glad its Friday Active Member

    That's not going to work - no live into the BDR91
    Doh
     
  10. Jitender

    Jitender Well-Known Member

    This is the wiring for a single channel Hive:


    [​IMG]


    I take it only needs L, N, common (1), and Heating On (3) connected?

    Just leave out the Heating off (2)?
     

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