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Honeywell CMT907A to Tado Smart thermostat

Discussion in 'Plumbing and Central Heating' started by Derek962021, 7 Feb 2021.

  1. Derek962021

    Derek962021

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    Hi,

    I'm trying to figure out the easiest way to fit a smart thermostat.

    I currently have a honeywell cmt907a backplate with cm907 thermostat on top which has two wires going into it... If I've looked at it right (photo attached).
    A: live
    B: switched live

    Other wires available are a blue (neutral) currently unused and green/yellow earth.

    I do not want to add any other wires such as a 230v live wire. The tado smart thermostat uses batteries I believe. Which wires would need to go where?

    I have a Baxi Duo-Tec Combi 28HE boiler.

    If any one has other suggestions for smart thermostats, feel free. Looking for something inexpensive I can control from my phone.
     

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  3. Derek962021

    Derek962021

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    From what I have read it seems that it should be wired as follows:
    A (live) goes to COM
    B (switched live) goes to NO

    Could someone confirm this is right?
     
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  4. Chris_W

    Chris_W

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    Yes this would seem correct, based on information you’ve supplied.
     
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  5. ianmcd

    ianmcd

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    You are confused , the Tado actual thermostat doesw not have any wires, it comes in 2 parts the thermostat and the receiver uni, the receiver need 4 wires , live , neutral and those 2 wires that are in the thermostat, if you simply want something to connect to those 2 wires that you can control with your phone and is battery powered go for NestE
     
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  6. Derek962021

    Derek962021

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    Thanks for your reply. I think this is incorrect though. From the Tado support site it says:
    "Hi! The Smart Thermostat is battery powered, which means it is compatible with almost any heating system (be it 2 or 3 wires, 230V or low voltage)."

    I understand that the reciever is not the same as the thermostat but from what I've read, it doesn't require 4 wires or wired power. I'll update the thread tomorrow when it arrives to help anyone else in the same situation.
     
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  8. ianmcd

    ianmcd

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    You can use the wires if you simply want to use it as a thermostat, but you want to control it with your phone so you need the extension kit
     
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  9. stem

    stem

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    There is a wired version of Tado for combi boilers that comprises a battery operated wired thermostat [so no wired bridge required] which would replace the Honeywell CM907. It comes with a separate internet bridge that provides the link to the internet. The internet bridge plugs into the router and is powered via a USB power supply.
    11.JPG

    The manual can be found here.
     
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  10. Derek962021

    Derek962021

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    Thanks! This is the version I went for deliberately to avoid needing wired power. Looks simple enough. Should arrive tomorrow :)
     
    Last edited by a moderator: 8 Feb 2021
  11. Derek962021

    Derek962021

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    This is incorrect. If you look at the post from stem above, you'll see the wired version doesn't require wired power and does work just the same (minus hot water control) as the other including smart features. Your phone talks to the internet bridge which sends messages out to the thermostats.
     
  12. Derek962021

    Derek962021

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    Just a final update in case anyone else would like to know. The above was correct. Live goes to COM and the switched live goes to NO. This is the wired starter kit V3. No power required as it runs on batteries. All smart features as expected
     
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