ecobee thermostat: “Calibrating”, or the thermostat keeps rebooting
The thermostat lost power and restarted. ecobee says it has no internal power source: it is powered by your heating and cooling equipment, and if that has no power the ecobee will not power on.
Applies to: ecobee smart thermostats. What you see: words.
What ecobee says to do
Wiring and power. ecobee ties this, on at least some systems, to the wiring, the power supply or the C wire. The steps here are only ecobee’s own, as its page states them; semiatic gives no wiring instructions of its own. ecobee’s own line on calling a professional is step 1 below.
- ecobee says an overheating furnace has safety equipment that cuts heating or power; its own fixes are to check and replace or clean clogged air filters, keep the air intake clear, have a furnace technician deep-clean it if filters are not the cause, and lower heat set points in very cold weather.
- ecobee says many boilers and zone valve systems, especially older ones, do not have a 24 VAC transformer with enough VA rating for a smart thermostat, and that most boiler systems need a separate 24 V 40 VA transformer for the ecobee.
- ecobee says that during cooling a blocked condensate drain line can trip a float switch or condensate pump that cuts power, and to clear the lines.
- ecobee says that if issues persist, consult your HVAC system’s manual or an HVAC contractor.
ecobee ties this to the boiler or heating system. What the symbols on a boiler’s own panel mean is on the boiler symbols page.
Source
ecobee’s own help page, read on the date shown.
- ecobee Support: Why is my ecobee thermostat rebooting? — ecobee smart thermostats (powered by the HVAC system’s 24 VAC supply). support.ecobee.com Checked 2026-09-29.