Amazon Smart Thermostat: what its lights, symbols and messages mean

The thermostat and your heating and cooling (HVAC) system did not connect with each other during installation. Amazon says the thermostat might need to install updates first.

Applies to: Amazon Smart Thermostat. What you see: words and a light.

What Amazon says to do

1. Allow a little time for the updates to install, then retry the installation.
2. To force the software to update: take the thermostat faceplate off and put it back after 30 seconds.
3. Close the Alexa app and restart it. If the Thermostat device page has a notification that installation failed, reinstall the thermostat; if that fails, Amazon says to contact Customer Support.

The thermostat has power and is waiting to be set up. Amazon says that if the display shows SEt or the temperature when you turn the power back on after fitting a C-wire adapter, it is connected successfully; SEt also appears at the end of a full factory reset.

Applies to: Amazon Smart Thermostat. What you see: words.

What Amazon says to do

1. Set it up in the Alexa app: Devices, then Add Device, then Thermostat, and choose Amazon as the brand.
2. After a full factory reset, first remove the old Amazon Smart Thermostat from the Alexa app (Devices › your Thermostat › Settings › Delete/Remove), then set it up again.

The thermostat is ready to reset. It shows rEs after you hold Up Temperature and Mode (partial reset), or Up Temperature, Down Temperature and Mode (full factory reset), together for 10 seconds.

Applies to: Amazon Smart Thermostat. What you see: words.

What Amazon says to do

1. To go ahead, press and hold the middle Mode button: the thermostat resets after a five-second countdown.
2. A partial reset (Up Temperature and Mode held for 10 seconds) erases everything except the HVAC configuration. A full factory reset (Up Temperature, Down Temperature and Mode held for 10 seconds) also erases the HVAC configuration and device settings.

After a partial reset, the red exclamation mark tells you the thermostat is ready to be set up again. Amazon says to wait for it before you start setup.

Applies to: Amazon Smart Thermostat. What you see: a symbol.

What Amazon says to do

1. Follow Amazon’s Set Up Your Amazon Smart Thermostat steps in the Alexa app to set it up and reconnect it to Wi-Fi.

You have an alert or notification about your thermostat. When the Info icon appears in red, yellow or green, Amazon says to go to the Smart Thermostat page in your Alexa app, where the alert itself is shown.

Applies to: Amazon Smart Thermostat. What you see: a symbol.

What to do

Amazon gives no step for this on the page cited; the meaning above is all it says.

Either the display has dimmed because nobody touched it, or the thermostat is not getting power. Amazon also uses a blank screen as the sign that the power is off before you work on the wiring.

Applies to: Amazon Smart Thermostat. What you see: a blank screen.

What Amazon says to do

Wiring and power. Amazon ties this, on at least some systems, to the wiring, the power supply or the C wire. The steps here are only Amazon’s own, as its page states them; semiatic gives no wiring instructions of its own.

1. Amazon says the display might dim when inactive: touch the display face to wake it.
2. Amazon suggests raising the display brightness for the thermostat in the Alexa app.
3. Amazon says to make sure all the wiring is correct, as in the Alexa app instructions, and firmly connected.
4. Amazon says to check the C-wire connection; a C-wire adapter is sold separately if you need one.
5. Amazon says to check there is no power outage and that your circuit breaker has power.
6. Amazon says to check for a blown fuse (3 and 5 amp) on the furnace board.

Heat mode is selected. Amazon’s heating check has you press the Mode button until the flame icon illuminates.

Applies to: Amazon Smart Thermostat. What you see: a symbol.

What Amazon says to do

1. To check that the heating comes on, Amazon says to press Mode until the flame lights, then press the up arrow until the setting is 1 or 2 degrees above the temperature on the display.
2. Amazon then has you check the outdoor unit: if it is running and blowing air, the system is a heat pump; otherwise it is a conventional system. Which one you have decides which wires its page tells you to check.