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 October 21

    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.


    n4h336gke100 heat pump.
    I feel like the emergency heat is turning on. Can someone confirm the Ecobee3 is wired correctly?

  • kevinmcckevinmcc Macomb, ILMember
    edited October 21

    @Haligan said:

    Your heat pump looks to be single stage, so no Y2. Was the black and white wire both connected to the W2 terminal on the old thermostat?


  • HaliganHaligan North CarolinaMember

    Thanks for the help. After reading your reply, I traced the wires, the black is not connected at the outside unit. Also the GREEN is not connected.

  • kevinmcckevinmcc Macomb, ILMember

    Check to see is Black is E or W on the furnace. Check other terminals on furnace such as green not being connected.

  • HaliganHaligan North CarolinaMember
    edited October 22

    Best I can tell, white and black connect together in the furnace. At one time this house had a large auxiliary heat strip in the attic and was removed. Could the white wire controlled part of the heat strip and black control the part? I have pushed the black in the wall.



    I scanned over the HVAC manual before I posted. How do you tell 2 stage or one stage?

  • kevinmcckevinmcc Macomb, ILMember
    edited October 23

    You would have Y and Y2 going at the heat pump terminals if you had two stage. Heat strips is a bit trickier. You would have to check the furnace manual and the furnace to see if you had multiple sets of strips. W1 and W2 for two stage heat strips. Sound like you only have one stage of heat strips and the black and white wires when to both, one was likely for W1 or W2 and the other for Emergency Heat. Some system require them both to work.

    Wiring labels for old system are those on the left side on the old thermostat.

    So now set to single stage heat pump with single stage backup strips, see how the system works.

  • HaliganHaligan North CarolinaMember

    I have not changed the wiring on the Ecobee3 from the above picture. Two nights in the 40's and I'm getting warm heat from the registers. It feels like the **emergency heat **is on also. I have checked the Ecobee3 and the dual heat setting is off. The system graph doesn't show emergency heat running but it feels like it. The only other idea I have is put the old one back on and run it a night.

  • whowho Member

    Currently, I have the Carrier Edge Program Thermostat. It's a 2 piece thermostat. First piece is near the furnace with all the wire then 2 wires from that piece go to display module on upper floor. I have an outside AC unit, inside gas furnace and humidifier.

    The wiring of first piece of my thermostat is
    Left side    Right side
    OAT          Rc
    RRS           Rh
    SRTN        W/W1
    HUM         G
    D1            Y/Y2
    D2            C
    V+            O/W2/B
    Vg             Y1/W2

    the wire configurations:
    Red -> Rc
    White -> W/W1
    Blue -> C
    Green -> g
    Yellow -> Y1/W2

    AC unit:
    Red -> Rc
    White -> Y/Y2
    Blue -> C
    Yellow -> Y1/W2
    Black -> OAT
    Brown -> SRTN

    Red-> HUM
    White -> C

    Display module:
    Red -> V+
    Black -> Vg

    I know I won't be able to use the OAT (Outside Air Temperature) from the AC, but can someone help with how to connect Y1/W2 to the Ecobee3 when Y1 and W2 are separated on the Ecobee3, and which slot do I connect my humidifier to? The 2 red/black wire connecting to the display module also has 6 other color wires so is it ok that I just use wire caps to connect all the wires of same code then put Ecobee3 on the upper floor?

    Thanks for any help.

  • kevinmcckevinmcc Macomb, ILMember
    edited November 4

    @who said:

    Y1/W2 is not Y1 and W2, but the terminal is one or the other. I am going to guess you have a two stage AC unit so the terminal is Y1, and not W2.

    The terminals are determined when you program the thermostat. Such as selecting single stage AC vs two stage AC, Heatpump vs AC, etc... The terminals can be used for other purposes depending on programming, this saves the manufacturer money by not having to add extra relays and terminals in the thermostat.

  • Dear forum ecobee experts,
    Anyone able to tel me if / how I can install an Ecobee 3 or 4? I have an Enviro-tec FCU, model VHC. The Fan Cool UNit itself is 108V, and the thermostat circuit has the words "High voltage" on it. But I also understood that could still mean the thermostat is 24V powered. I have attached pictures and links of the diagrams for both:
    FCU unit
    photo 1
    Photo 2
    The wiring is unclear for me. Anyone any ideas if, and how I could make it work?
    Thanks, Mick

  • kevinmcckevinmcc Macomb, ILMember
    edited November 25

    @mspaanm said:

    Unfortunately you can not use Ecobee 3 or 4 directly. The system uses a high voltage thermostat / control.

    You may be able to get 24vac transformer and some isolation relays to allow Ecobee to control the system. You would need a competent local electrician / electrical engineer to make sure your relays are properly rated for the motor control part and make sure the wiring is correct. You should be able to convert for fan speeds (Y1, Y2, W1, W2), fan only (G, low speed), heat and cool if you have both. I do not know if there is anything already on the market for this, but having someone do a design, buy parts, rewire, that will not be cheap.

  • Thanks for letting me know. Wow that is too bad, I was really hoping to get a smart thermostat that would work with Amazon Echo. The steps you described sound pretty complex, and/or too expensive to be worth it. I read something about https://getmysa.com making high voltage smart thermostat, but these only work for "electric boards". I have a Fan Coil Unit, sounds like something different.

  • kevinmcckevinmcc Macomb, ILMember

    @mspaanm said:

    If you look in the thermostat guide for your system you will see there is blower motor speed control and valve control. You would need a thermostat that can do both.

  • shirlytangshirlytang LouisianaMember
    edited November 28

    I have an e3 lite. It ran great during summer. Now I need heat and if its on thermostat it blows cool air, HVAC it doesn't blow any air. I have C wire upstairs, but not to the thermostat, so I installed the PEK. There is a blue wire at the thermostat. Didn't think to look for a blue wire upstair to the HVAC system. Any thoughts?

  • kevinmcckevinmcc Macomb, ILMember

    Need more details. Can you get pictures of wires at furnace and at thermostat?

  • byoung2byoung2 CaliforniaMember

    I’m having some install problems with the ecobee3. I installed the thermostat and it started up no problem.. I then noticed the AC fan running the whole time.. I removed the face and the AC fan stopped.. Here’s a picture of the wires at the thermostat and the furnace.. Any help getting the AC fan to stop running would be appreciated. Thanks!!


  • kevinmcckevinmcc Macomb, ILMember

    @byoung2 said:

    Wiring should have been straight forward. Same terminals, just no jumper.

    Make sure you Ecobee fan control is set to HVAC and not thermostat.

  • byoung2byoung2 CaliforniaMember

    Thanks kevinmcc I’ll give it another try

  • byoung2byoung2 CaliforniaMember

    Tried it again selecting HVAC to run the fan but it still continues to run

  • byoung2byoung2 CaliforniaMember
    edited December 3

    @kevin_mcc said:
    Tried it again selecting HVAC to run the fan but it still continues to run. Also I raised the heat temperature and it states the heater is running but no heat out of the vents

  • kevinmcckevinmcc Macomb, ILMember

    @byoung2 said:

    Pictures are not showing now. Terminals should be like other thermostat. I did notice in the pictures the wires were stripped back a bit too much on old thermostat. Make sure the are pushed in the Ecobee and not much exposed wire remains out side. Go through install setting make sure everything is correct for your furnace type. I believe you have just AC and furnace, make sure not to select heat pump. If heat is being called you can check at furnace with multi-meter. You should get 24vac between W1 and C. Call Ecobee support if you can not get the Ecobee working. You could also have a defective unit.

  • Looking for some help. I have had my ecobee installed for a year but just had a new furnace installed. Old one was single-stage, new one is 2-stage with variable speed (Carrier Performance). The HVAC guys connected the ecobee, but am not sure whether there are settings I should be changing? When I go into advanced settings it says ‘furnace 1 stage’ and the ecobee is controlling the fan. Is it not wired correctly to realize it’s 2-stage, or do I need to do a reinstall of the ecobee, or...? So much of what I can find online is about installing an ecobee when replacing an existing thermostat - haven’t had much luck finding info on an existing ecobee and new furnace.

  • kevinmcckevinmcc Macomb, ILMember
    edited December 9

    @types24 said:

    For two stage you need to have wires for W1 and W2. W1 is the first stage and W2 is the second stage. The furnace board then needs to be set for the thermostat to control staging. There should be a switch on the furnace board for that and will be discussed in the installation manual. The Ecobee go to Main Menu > Settings > Installation Settings > Equipment > Furnace and change the settings you need. If that does not work try Main Menu > Reconfigure, but we warned that will erase your existing configuration.

    If the furnace was just installed with W1 only, there are switches on the furnace board that control how stage 2 will activate. Typically stage 1 will run for several minutes then stage 2 will turn on. The furnace install manual will discuss those switches and the timings.

  • @kevinmcc said:
    If the furnace was just installed with W1 only, there are switches on the furnace board that control how stage 2 will activate. Typically stage 1 will run for several minutes then stage 2 will turn on. The furnace install manual will discuss those switches and the timings.

    Thank you! It looks like my only wiring coming from the thermostat (and ecobee PEK) is for W1 (though I didn’t open the PEK to check my wiring), so it looks like I’m in the latter scenario where the furnace is in charge of activating 1st vs 2nd stage heating. Any thoughts on whether the ecobee tstat or the furnace are better at managing the 2-stages? (I assume if ecobee is better, then I’d need someone to run another wire to the tstat?)

  • kevinmcckevinmcc Macomb, ILMember

    Ecobee will be better at controlling stage 2 run times, but that sounds like you would need new wiring or a fast-stat wiring extender since the PEK does not not have W2.

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