Nest Gen3 Thermostat Multiple Issues After Years Of Flawless Service

[BostonNest]

Nest system was installed by our HVAC company ~3 years ago and has worked mostly flawlessly (exception for having to periodically unplug and charge during the summer when not able to steal power from the heat).

Two weeks ago our third gen learning nest stopped working (It gave us a few different errors but mostly e80). I tried all the normal things and couldnt figure it out so I called our HVAC company to take a look.

They checked everything and determined that the nest baseplate was shortcircuited. I ended up just buying a new 3rd gen and replacing everything. It worked fantastic for 12 hours but when I woke up I was greeted with "Please Remove Thermostat From Its Base and Reconnect". I tried a few times, restarted the thermostat, and tried charging with a USB cable (unit does not show a green blinking light like it should). No matter what I do I cant get it to go to any other screen except the "... please remove...".

Frustrated, I plugged in our old nest 3rd gen - That now prompts me with the same e80 error as before.

We have 4 other Nest thermostats (not learning) that do only heat and have been working flawlessly throughout all of this.

Any ideas? Im tempted to call my HVAC folks back - they're awesome but not nest experts.

[Patrick_Caezza]

Post a picture of how the Nest thermostat is wired.

Does it have a C wire installed? It sounds like it doesn't have one if you have had to keep charging it with a USB cable all this time. 

[BostonNest]

Hey! It doesn't have a C-Wire but i'm ok with charging it periodically outside of the problems listed 

[Patrick_Caezza]

The problem you are having is that it doesn't have a C wire.

The internal batteries will start to lose the ability to fully charge after several years, just like your cell phone.

I have no idea how your HVAC people decided that the base was shorted out since it is full of solid-state relays and such.

[Jeran]

Thank you for helping out on this thread, Patrick_Caezza!

Hey there BostonNest,

I'm just checking up on this thread, do you have any more questions or need any additional help? 

Best regards,
Jeran

[EmersonB]

Hi everyone,

@BostonNest, we wanted to follow up and see if you are still in need of any help. Please let us know if you are still having any concerns or questions from here, as we would be happy to take a closer look and assist you further.

I appreciate the help, Patrick_Caezza and Jeran.

Best,
Emerson

[EmersonB]

Hey BostonNest,

Just one quick final check in here since activity has slowed down. We'll be locking the thread in the next 24 hours, but if you still need help, we would be happy to keep it open. If there's more we can do, just let us know.

Thanks,
Emerson