The thermostat has no power. The C-wire is not connected or the furnace door is open.
- Go to your circuit breaker box. Find the breaker for your heating and cooling system. Flip it off, then back on.
- Go to your furnace or heating system (basement, attic, garage). Make sure its power switch is on.
- Check that the furnace door is closed completely. Some systems won't power up if the door isn't fully shut.
- Verify the C wire is connected at both the thermostat and the furnace control board. At the furnace, find the bundle of wires. The C wire should be secured under the C-terminal screw.
IF THAT DIDN'T WORK: If you don't have a C-wire connected, you must use the included C-Wire Adapter. Your system requires 24 VAC power from a C-wire or the adapter to operate.
HEADS UP: Always turn off power at the breaker before checking or connecting any wires at the furnace. Electrical hazard.