Nest Smart Learning Thermostat no power and batteries drained

[Louise5]

I've had my nest for 8 years so this isnt a starting up issue. Last week I unplugged my thermostat for 5 seconds to move some shelves and I straight away got a power warning when I plugged it back in. Saying the wall power wasn't connected, when it was.  

I followed online advice to restart my thermostat, but this didn't work. The next advice was to reinstall the back up batteries, but I can't access these bc my thermostat had a back plate with a werid Alan key shape I haven't seen before. The back up battery has now died and I don't know how I'm supposed to fix this. 

Thank you for your help!!

[Louise5]

I should add. The thermostat has been plugged into power at the wall all week! And still doesn't think it's receiving power. And Yes, I've tested the wall plug and ut does work.

[Jeremyg]

Hi @Louise5,

Thanks for reaching out to the community. I am sorry that you are having issues with your thermostat, but no need to worry; help is here.

We appreciate all of your previous troubleshooting efforts to connect with our community. I am aware that you did restart the Nest ThermostatI need to know a few things about your thermostat in order to provide you with a better resolution.

• What Nest thermostat model do you have? For your reference, you can check out this article on How to Tell Which Nest Thermostat You Have.
• Does the thermostat display show any error codes or messages?
• When did the issue first occur?
• When was the thermostat installed?
• "What is the make and model of your HVAC equipment?
• How long did you charge the thermostat with a USB cable?
• Do you see a blinking LED light? If so, is it red or green?
• Does your thermostat have a C wire? 

I'll be waiting for your response; any additional details you can provide will be helpful.

Best regards,

Jeremy.

[Louise5]

Hi Jeremy,

Model  Display-3.4

Black Plate Model Backplate-6.5

Serial no ################

My nest was installed about 7 years ago and only got this problem 3 weeks ago when I briefly unplugged the thermostat from the wall power socket. It's been plugged in the a wall power socket for the whole time I've had it.

There was an error, which stated a heatlink issue, but now the internal battery has run down its just black.

The heatlink has a slowly flashing light blue light.

Thank you!!

[Jeremyg]

Hi @Louise5,

Thanks for the update and letting us know that information that is going to help me to better assist you.

Could you check the power reading of your Nest Thermostat by going to Settings > Technical Info > Power?

Could you also share the VOC, VIN and IIN readings? Also, how is your Nest Thermostat wired?

Here are some additional troubleshooting steps that might be helpful:

• Use a mini USB cable
  
  
• Insert the USB cable to the the Nest Learning Thermostat 3rd gen
  
  
• Plug the other part of the mini USB cable into a power outlet
  
  
• Leave the device charging for more than 2 hours.

Regards,

Jeremy

[Louise5]

Hi Jeremy, I can't view the status bc there is no.power.

The thermostat has been plugged in via USB c to power for the last 3 weeks since this issue started, and has always been plugged directly into power via USB c for the last 7 years.

It just isn't receiving power any more, and I don't know why

[Jeremyg]

Hi @Louise5,

Thank you very much for the update. In this case, we have already checked the device. The next step is to see the voltage that is coming from the HVAC system. Therefore, this situation needs further assistance please Please fill out this form with all the necessary information, like the thread title or link and your username in the community. Once you've completed the form, let me know. Someone from my team will contact you shortly to help

Regards,
Jeremy.