I have an Ecobee thermostat. I just noticed that the screen is completely blank, and it does not appear to have any power to it. It was working fine a few days ago. Any tips for troubleshooting before I call an HVAC company?

I would check the following before calling your repair guy:

1.) AC Breaker.
2.) Any power switches associated with the system...make sure they are 'on'.
3.) AC Float Switch (if present, should be on the condensate drain line near the unit). If it is tripped (by a clogged drain line), it will turn the power off. You should unclog the drain line to get it going again.

This happened to us a few months ago and it turned out that we have light switches in the attic that control the HVAC units and my wife accidentally flipped one off when taking down the Christmas decorations.

HeightsAg said:

---

This happened to us a few months ago and it turned out that we have light switches in the attic that control the HVAC units and my wife accidentally flipped one off when taking down the Christmas decorations.

---

THANK YOU! As soon as you said that, I knew that this is exactly what happened. I had been in the attic yesterday, and must have accidentally flipped the HVAC switch when I was leaving.

Keep the list from dudeabides. Just tape it to your thermostat. If all 3 of these result in no joy, its time to call the HVAC guy.

I had a float switch that foiled me for hours. Thermostat would go dead. I would check switch and breaker. Nothing. Then it would come on. Then back off.

Typically though with a breaker its going to be the condenser breaker and you will notice regular air blowing vs cold air. A condenser throwing a breaker is often a sign other things are amiss.

There is also a low voltage fuse in most air handlers but this usually blows when first installing the thermostat or when you weed eat the wires running to the AC compressor and have to splice them together. Its usually a auto blade type fuse.