Honeywell thermostat: Alert code 171: set the date and time
A reminder to set the date and time.
Applies to: T6 Pro thermostats. What you see: a code and a symbol.
What Honeywell Home says to do
- To view, snooze or clear it: press Menu until the screen shows ALRT, press Select; press Select again to snooze for 7 days, or press + until it shows CLER and press Select to clear.
Source
Honeywell Home’s own help page, read on the date shown.
- Honeywell Home (Resideo) documentation: 7. Alerts and Reminders — T6 Pro Installation Manual — T6 Pro thermostats (codes 177 and 178 not on the TH6210U). docs.honeywellhome.com Checked 2026-09-29.
A similar symbol on other thermostats
The same symbol on another maker’s thermostat can mean something else.