Picture of the Honeywell RTH9580WF Smart Thermostat, displaying the Boot screen.

How to Restart a Honeywell Thermostat

You may wish to reboot your Honeywell thermostat if it starts behaving strangely, freezes, hangs, does not turn on or off the furnace even though the current temperature and current setting are far apart, will not connect to Wi-Fi, is not properly sending information periodically to the Honeywell Total Comfort Connect servers on the internet, et al.

Before attempting any extensive thermostat troubleshooting, always try a restart first. This often clears up many problems described above.  Plus, trying a system restart initially avoids the potentially unnecessary action of hard resetting your Honeywell thermostat, in which all the onboard settings are erased.


Honeywell Thermostat Restart Method One: Power Cycle the Furnace

Your furnace supplies power to most Honeywell thermostats. Also, many later Honeywell thermostats feature a wall bracket from which the thermostat can simply be unsnapped from, instantly disconnecting the thermostat from the furnace and thus, deactivating the thermostat.  If yours is this way, then to power it down, simply grasp the top and bottom center edges of the thermostat, and gently pull out and away from the wall bracket.

However, if your Honeywell thermostat is “hard wired” and therefore does not simply unplug from the wall, then you’ll have to momentarily disrupt power to it as follows.

Locate the furnace power on / off switch.  Typically this resembles a wall mounted light switch.  Or if you don’t have a switch, then perhaps the furnace itself has a power cord that is plugged into a nearby wall outlet.  Unplug this to power off the furnace and thermostat.  But if you have neither a power plug nor switch for the furnace, then locate its circuit breaker / fuse in you main service panel box, and turn it off there

With the thermostat no deactivated, remove its battery if your thermostat has one.  Then, verify that thermostat screen has gone completely blank and dark.

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

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

Rebooting is complete when the thermostat displays, depending on the model, the indoor temperature and current temperature setting.  You then may have to reset the thermostat’s clock, for non internet enabled thermostats.

Picture of the Honeywell RTH9580WF Smart Thermostat, front view after restart.
Honeywell RTH9580WF Smart Thermostat, front view after restart.


So far, we are unaware of any means to restart Honeywell digital thermostats remotely.  Neither the Total Comfort Connect website nor the corresponding app for mobile devices, provides this option as of this writing.  So, rebooting can currently only be done if you’re close enough to physically cut off the power to the thermostat or the furnace supplying it.


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Revision History

  • 2017-01-29: Originally published.