topic Re: Nest thermostat E261 in Nest Thermostats

Nest thermostat E261

Whitlebloer — Sat, 10 Sep 2022 01:10:50 GMT

I have an issue where the C-wire kept dropping off. When I originally installed the thermostat, all wiring appeared to be fine. But after a day, an error E261 appeared which was low power on the C-wire. So I pulled out the face cover of the thermostat thinking maybe the connection was not tight, I checked the voltage of the red and black wires and there was always 2.7+ volts. When I pushed it back in again, everything was running normal again. In the meantime my battery ran out every 2 days. After a few mishaps like that, I requested a replacement from Amazon for a new unit. What I found was the new nest thermostat was even worse. In less than 24 hrs I got a notice of low battery and the same N261 error appeared.

So I called Nest Customer Service who asked me to read the power etc. A day later, I have exactly the same problem I had with my 1st nest thermostat. I was wondering if I have a bad unit replaced by another bad unit because the C-wire has power.

I am posting the pictures of the wiring of the old thermostat and new Nest thermostat. In the picture, the C-wire is black. The blue wire is a spare wire and was never used. I am still looking for the solution before returning them back to Amazon.

Re: Nest thermostat E261

Patrick_Caezza — Sat, 10 Sep 2022 01:29:43 GMT

Take a look at the terminal block on the control board in the furnace/air handler and verify that the black wire is in fact connected to the C terminal.

Re: Nest thermostat E261

Whitlebloer — Sat, 10 Sep 2022 16:39:09 GMT

If the C-wire is not connected at the furnace, do you still have a reading of 2.7+ volts ? Thank you.

Re: Nest thermostat E261

Ryan_G — Thu, 15 Sep 2022 12:44:15 GMT

Hi Whitlebloer,

Thanks for reaching out and we're sorry for the delay.

The Nest Thermostat should always be receiving more than 3.6V to ensure the battery is staying charged. That can be achieved by connecting a C wire to your thermostat.

Regards,

Ryan

Re: Nest thermostat E261

Jake — Mon, 19 Sep 2022 17:49:50 GMT

Hey Whitlebloer,

I wanted to check in and see if you managed to see Ryan's post. Please let me know if you have any questions from here. I would be happy to assist, and make sure you are good to go.

Best regards,
Jake

Re: Nest thermostat E261

Jake — Tue, 20 Sep 2022 16:36:15 GMT

Hey Whitlebloer,

I want to ensure you are good to go, and everything is working properly. Please let me know if you are still having trouble, as I will be locking the thread in 24 hours due to inactivity.

Best regards,
Jake