Thermostat help

If your voltage is too low, the thermostat will turn off the WiFi feature. It needs 3.7V to function properly.

Is your Nest powered by a common (C) wire? If not, perhaps you should hook one up - hopefully you have a common wire already there, not connected, you can use. Perhaps this article might help you trouble shoot assuming you have have not read it already LINK

FWIW, just passing this along, professional HVAC techs on the HVAC-Talk do not like Nest thermostats - they say they fix a fair number of problematic HVAC issues by simply replacing Nest thermostats. They like Honeywell and Ecobee smart thermostats. But that said the problem you are describing doesn’t sound like the problems they describe with Nest though I think I recall connecting a C wire helped to solve some Nest issues.

ETA: I linked one thread from HVAC-Talk where HVAC techs discuss issues with Nest thermostats relative a question that a homeowner had with a HVAC issue - you need to read 7 posts down where the issue with Nests come up. LINK

Yeah if he’s gone through 3-4 thermostats, request a refund and go with a different brand.

I’ve installed/own 4 Nest thermostats. Haven’t had any issues with them, but one of my clients is an A/C company and he said they never get calls about Nests working perfectly He thinks about 15-20% of homes aren’t compatible with Nest

I do have a C wire connected. When we installed the thermostat we ran a brand new line to the board so that we would have a C wire. If I remember correctly the original line only had 4 wires. It's weird that this happening because the original thermostat worked fine for over a year and now all of the replacements are crapping out within a month or so.

The unit does have a usb port on the back but I think it may be for only charging the battery. When disconnected from the base and plugged into a usb charger you cannot use the thermostat, no functions work and it displays a message that says to connect it to the base to use.