Our Honeywell T6 ZW is showing powersource as "battery" despite it being set up by an HVAC installer using C-Wire (24 VAC). Am unable to recheck the Power Source on the thermostat as it's a vacation home, miles away, but it definitely stated 24VAC powered when I last checked it.
Stat is responding and functioning perfectly.
Could this just be the app displaying wrongly or is it possible for the T6 to switch from AC to battery without warning (other than on power cut) ?