No Power to Google Nest Thermostat after changing batteries

[rcarpenter78]

After changing the batteries to our Google Nest Thermostat, we plugged the Nest back into the wall and are now getting a No Power message (e298) and the wires are all listed as grey. Battery is good. Please help, we are in a heat wave!

[Houptee]

Does it light up and can you get to the diagnostic test to see what it says for voltage on Rc and common? Should be around 28 v AC give or take. If no voltage on Rc to common then the problem is in the system. Some control boards in the air handler have a fuse that could have blown.  They look like car fuses that plug in. If not then test with multi meter for the voltage at the transformer using a multi meter. 

[Ryan_G]

Hey rcarpenter78,

Thanks for reaching out here in the Google Nest Community.

I'd like to jump in here and check if you've seen Houptee's response. It was a really good check for us to further isolate the issue. The error code E298 means that Nest Thermostat is not getting or detecting any power from your HVAC system. 

Let us know how it goes by replying to this thread.

Thanks for your helpful troubleshooting, Houptee.

Best regards,

Ryan

[Ryan_G]

Hey rcarpenter78,

I just wanted to follow up and see if you're still in need of help. Please let us know as we would be happy to answer any questions you may have. 

Best regards,

Ryan

[Ryan_G]

Hey there,

Thanks for being here in the Google Nest Community. 

I'd like to bump in here and make sure that you’ve seen our response.

Please let us know if you have any other questions or concerns as I will be locking this thread in 24 hours.

Have a great day.

Best regards,

Ryan