Change battery located on back of thermostat??
Go to google
Search for your model number 1234XX .pdf
Add .pdf in search parameter.
Honeywell posts most their thermostat manuals.
Open pdf file, and then Use Ctrl+F for search feature
Word-Search manual
To find model number on thermostat, remove from wall.
Model number appears on back.
Don't forget to replace battery while you have back exposed.
Dead battery can also cause lockout and malfunction
If you need further help, I’m available over the phone at
https://www.6ya.com/expert/gene_9f0ef4df2f9897e7
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