If you're posting a request for installation help, please provide as much info about your system as possible. For example, for help regarding connecting a smart thermostat, please include details about your system including whether you have gas/electric, heat pump, number of heat stages, A/C condenser, etc.

ecobee 3 Install Help Thread



  • kevinmcckevinmcc Macomb, ILMember

    @AlexK91 said:

    You have a communicating thermostat by the looks of it.

    Is there a black wire at the thermostat? The furnace shows a black wire to C.

    Should be repetitively easy to wire, but we need more information about your furnace before we can make suggestions. What is the make and model of your furnace.

  • AlexK91AlexK91 Member
    edited July 20

    @kevinmcc said:

    Thanks for the reply Kevin, no there is not a black wire at the thermostat. I double checked right now and the only cables are the ones visible in the pictures I posted. The dark cable is actually brown in color, not black.

    My furnace is a Trane XC95m model number TDHMC100ACV4VAB.

    To answer Larry's questions from the previous post, we do have heating and cooling in the house with the way the system is currently wired.

  • kevinmcckevinmcc Macomb, ILMember
    edited July 21

    @AlexK91 said:

    I wonder if there is a spice in the middle between Furnace and Thermostat. No brown wire at thermostat either?

    I did find the install manual if we figure the wiring bit out.


  • chad.jochad.jo Chicago, ILMember

    I need some advice for my Ecobee 3 installation. There’s no C wire at the thermostat; so I know I have to use the Power Extender Kit. But back at my HVAC control board, there’s already a C wire that runs somewhere else. (I can’t see where it goes…maybe to my humidifier?) My plan is to remove that C wire (and the other four wires) from my HVAC control board, and connect all five wires from the PEK to my HVAC control board according to the standard directions. Can I also the connect the original C wire to the PEK to make sure there’s still power supplied to whatever it’s supplied to now? In other words, can I have two C wires connected to the C terminal on the PEK…one for the kit to supply power to the Ecobee, and the other to go wherever it goes now? Thanks!

  • kevinmcckevinmcc Macomb, ILMember

    @chad.jo said:

    I commented on your other post.

  • HaliganHaligan North CarolinaMember
    edited 1:27AM

    I removed a standard thermostat in the spring and installed an Ecobee3.
    Old thermostat.


    I have a heat pump with electric emergency heat. But I do not know if it is two stage or single stage. Here is how I have the Ecobee3 wired.


    I feel like the emergency heat is turning on. Can someone confirm the Ecobee3 is wired correctly?

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