What happens to my thermostat settings when I replace the batteries?
The thermostat does not lose any settings when the batteries are replaced; all settings are permanently stored in memory. This means your temperature settings and system preferences will remain unchanged after you install fresh batteries. (Page 9)
From the official Honeywell TH5110D Home Programmable Thermostat manual, page 9
Have a follow-up question?
Answers from the official manual.
Common questions