Nest E Error E194 - Not connecting to Power or Wifi

[KatieHoil]

I had a handyman friend install our Nest E thermostat from a Honeywell. He didn't use the labels. Everything worked fine for a while, but then the wifi suddenly stopped connecting and when I looked closer, I realized it had a low battery and saw an E194 error. I'm trying to troubleshoot, but am confused by the wiring without those labels.

It looks like there is a black wire unused. Could this be the C wire required for power and wifi?

[Patrick_Caezza]

You need to add a C wire.

Sometimes the HVAC system doesn't like how the Nest powers itself and you then have to install a C wire.

Check for a spare wire behind the thermostat to you can use, or you can install the Nest Power Connector

[KatieHoil]

Thanks so much! There is a black wire (you can barely see it in the middle of the wires in the picture) Do you think it is safe to assume that would work?

[Patrick_Caezza]

Check its other end in the furnace/air handler and if it is also not used there you can use it for a C wire.

[EdwardT]

Hi folks,

@Patrick, thanks for the help!

@KatieHoil, how's it going with your Google Nest Thermostat? Still need our help?

Thanks,

Edward

[MelbaDT]

Hey KatieHoil, 

Checking back in — how's your thermostat now? Let us know by replying to this thread if you still need help with it. 

Best, 

Melba

[MelbaDT]

Hi, 

We haven't heard from you in a while so we'll be locking this thread if there is no update within the day. If you have any new issues, updates or just a discussion topic, feel free to start a new thread in the community.

Best, 

Melba

[KatieHoil]

Thank you! I've tried to connect the black wire and nothing happens. The Nest face doesn't turn on at all. Removed that black wire from the C and works fine again, just no power or wifi. I guess this means I have to pay someone to come help me install a C wire or a Nest Power Connector. Not sure how I decide which one in order to schedule someone. I hate all of this so much!! I just want it to work!!

[EdwardT]

Hi KatieHoil,

Thanks for the update. I understand how frustrating it is to get your Nest Thermostat to work. You could click on this link to learn about our Nest Pro services to install your C wire.

Thanks,

Edward

[EdwardT]

Hi KatieHoil,

It's me again. I wanted to check back in to see if you have other questions and concerns. Feel free to let me know if you do. 

Thanks,

Edward

[MelbaDT]

Hi, 

We haven't heard from you in a while so we'll be locking this thread if there is no update within the day. If you have any new issues, updates or just a discussion topic, feel free to start a new thread in the community.

Best, 

Melba