I disconnected my previously working ecobee to go back to traditional non WiFi Honeywell thermostat that was installed before the ecobee3.

The Heat works good but when I try to turn on AC it just won’t kick on. Thinking I connected the, back incorrectly, can’t seem to figure it out. I attached an image of my thermostat wiring and furnace wiring.

The AC common wire (white) is going to T terminal since I don’t have a C. The AC Y (Red) wire is going to the Y terminal.

Any advice it tips would be greatly appreciated.

enter image description here enter image description here enter image description here

  • Can you post a photo of the wiring at the thermostat end? – ThreePhaseEel Jun 30 at 2:25
  • Which wires were connected to the controlled contacts on the thermostst you removed? Those are the wires that should be connected to the contacts on the replacement stat... – Solar Mike Jun 30 at 4:33
  • Thank you for the feedback, I have included a photo of the thermostat wiring. – Pennysavin03 Jun 30 at 13:31
  • When I disconnect the AC wiring I was able to ensure the other four terminal points at the furnace panel board and the thermostat matched. Now I am having trouble determining how the AC should be hooked back up. – Pennysavin03 Jun 30 at 13:34
  • First thing I suggest is to shorten the copper without insulation on the thermostat - a short waiting to happen... – Solar Mike Jun 30 at 13:35

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.