I have an Ecobee3 that has been successfully working (both heat, fan, and AC) for the past 6 months. Recently I was trying to get my humidifier working so I was playing around with some wires, which also involved turning on and off the heat/power many times (I think this is what caused the issue). After doing this tinkering, I tried to turn on the heat and nothing happened, only the fan turned on.

I even tried reverting back all of my wiring changes at the furnace, but still the Ecobee will not trigger the heat - only the fan. The furnace has the correct light on, meaning it is operational. I reinstalled the old thermostat and it is working as expected (heat + fan). I then re-installed the Ecobee and when I turn on the heat only the fan starts up - the heat doesn't even attempt to kick on.

When I have the heat on, the Ecobee indicates that the "running equipment" is the fan AND heat (even though the heat is not on).

I tried resetting the Ecobee completely to no avail. I double checked wiring and it is all as I left it. (Note: when doing my humidifier work, I never touched the Ecobee wiring).

Is there a "glitch" the my Ecobee to be causing this out of nowhere?

ecobee wiring

furnace wiring old thermostat wiring

1 Answer 1


I called Ecobee support and ran through quite a few troubleshooting steps to figure this issue out. It was determined my Ecobee had a blown fuse and they are sending a replacement.

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