How to Restart Honeywell Thermostat

Honeywell RTH9580WF Smart Thermostat, displaying the Boot screen.

You may wish to learn how to restart Honeywell thermostat if it behaves strangely. For example, it may freeze, hang, or not work the furnace. Or, it does not connect to Wi-Fi, or sends no data to the Honeywell Total Comfort Connect servers. Any of these issues a restart might fix.

How to Restart Honeywell Thermostat: When to Restart

Before doing any thermostat troubleshooting, always try a restart first. Restarting often fixes many problems. Plus, trying a system restart first may save you from a hard reset of your Honeywell thermostat.

Restarting involves less than hard resetting. Why? Because it saves the onboard settings. These do not erase in a restart. So if restarting, you need not figure out how to fill in these settings later.

How to Restart Honeywell Thermostat: Take Thermostat Off Wall

Honeywell RTH9580WF Internet Thermostat, being snapped onto wall plate.

Your furnace supplies power to most Honeywell thermostats. Also, many later thermostats have a wall bracket. From this, you detach the thermostat. Detaching disconnects the thermostat from main power. If yours is this way, power it off as follows.

Simply grasp its top and bottom center edges. Then gently pull the t-stat out and away from the wall bracket.

Then, wait a few seconds.

Finally, reattach the thermostat to the wall bracket. Restart should begin shortly after.

How to Restart Honeywell Thermostat: Power Cycle the Furnace

Turn Power Off at Furnace

Perhaps your house has a “hard wired” thermostat. So, it does not simply unplug from the wall. In that case, stop power to it as follows.

Find the furnace power on / off switch. This looks like a wall mounted light switch. Or if no switch, then check at the furnace. Perhaps the furnace has a power cord plugged into a nearby outlet. Unplug this to power off the furnace, and thus, the thermostat.

Turn Furnace Power Off at Main Service Panel

But if you have neither a power plug nor switch, then head to the main service panel. There, find your furnace’s circuit breaker / fuse.

Finally, flip that breaker off or pull the fuse.

Remove Thermostat Battery, if Any, to Continue with How to Restart Honeywell Thermostat

With the thermostat now OFF, remove its battery if your thermostat has one. Then, check that thermostat screen is blank.

When the furnace / HVAC system is OFF, so too should the thermostat be dark, as shown next.

Honeywell RTH9580WF Internet Thermostat, mounted but powered down, snapped onto wall plate.

Wait a Bit

Wait at least ten seconds. Then reinstall the thermostat battery if you previously removed one.

Turn Power Back On

Then turn furnace / HVAC power back on. Digital Honeywell thermostats typically complete rebooting in less than a minute.

The Boot screen.

Smart thermostats finish rebooting, when they show the indoor temp and current temp setting. You then may have to reset the thermostat’s clock, for non internet models.

How to restart Honeywell thermostat. The Honeywell RTH9580WF smart thermostat, front view after restart.

So far, we know of no way how to restart a Honeywell thermostat remotely. Neither the Total Comfort Connect website nor that app for mobile devices, lets you do this as of this writing. So, you can reboot only if you cut power to the thermostat or furnace.