Low power, disconnects from wifi

[jschneider]

I have lived in this house for about two years, and it already had the Nest installed when we moved in. We did not have any issues until last fall when it disconnected a couple of times with the low power message. Then we didn't have any issues during winter, and now through spring it has been a daily issue disconnecting and saying low power. I assume the battery is going bad and the intermittent heating/cooling is no longer enough to power the thermostat.

So I installed the Nest Power Connector and made sure the thermostat was fully charged with a USB cable. That worked for about three days, and now its back to disconnecting daily. I attached two pictures which were taken before I installed the power connector at the furnace. I have a W1 wire for heating, Y1 for cooling, G for the fan, and Rc for power. As you can see, there is a separate black/white wire going to the C terminal and Y terminal at the furnace. It would make sense to me that that is the power to the AC unit, so does that mean I don't actually have a C wire at the furnace? I know there is no C wire run to the thermostat itself.

While looking at the thermostat's tech info page, the battery voltage seems to bounce between 3.6xxV to 3.7xxV and lin is 40 mA (was 20 mA before I installed the power connector). Does anyone know what the voltages on the wires at the thermostat should be (using a voltmeter)? If that would even help troubleshooting?

I'm pretty handy and might be able to fish a C wire up the wall to the thermostat, but I'd like to avoid that if I could. I just don't see any other trouble shooting instructions.

[Markjosephp]

Hello jschneider,

Thanks for reaching out to the Google Nest Community Forum.

I appreciate you sharing your Nest Thermostat and your HVAC system wiring setup. It appears that your thermostat isn't receiving enough power, which causes it to disconnect from the Wi-Fi network in order to save the battery. However, I see that you have a C wire installed from your control board. You might want to check where the end wire is so we can install it on the Nest Thermostat.

In addition, to avoid power loss, I'd suggest installing a Nest Power Connector as an alternative to the Common wire. Here's the article about the Nest Power Connector and how to install it with your control panel.

Let us know if you have more questions.

Regards,
Mark

[Markjosephp]

Hey there,

I wanted to see if you still needed help. Please let us know if you have any other questions or concerns.

Thanks,

Mark

[Jenelyn_O]

Hey jschneider,

Due to inactivity, we'll go ahead and lock this thread in 24 hours. We'd be glad to help you further so if you still need assistance, feel free to start a new thread.

Best,

Jenelyn