I have a Honeywell Chronotherm IV Plus T8601D2019 thermostat. And this morning I notice the house was getting cold I checked the thermostat and the screen was off nothing works the no lights. And there is no battery in the back

Hi, maybe try 1st to add a battery in the back and see if its going to work, maybe it fall out or someone was just playing with it??

Hi thanks for the quick response, but there is no battery on this model

OK let me check it out, will try to get an answer for you

This might help you out, try let us know.

https://www.askmehelpdesk.com/heating-air-conditioning/honeywell-thermostat-continous-clicks-fade-issue-389354.html

Hi. If the thermostat doesn't take a battery, then the stat is powered off the furnace. Check furnace breaker and any fuses. If the furnace doesn't have power to it, the stat will be blank. Hopefully its as simple as a blown fuse in the ssu on the side or near the furnace, or a fuse on the low voltage side of the transformer or on control board. Please let us know what you find.