Nest thermostat continues to show no power.

[tbruce0]

I have 2 nest thermostats in my house already.  Today I attempted to add a third, and no matter what I do I get "no power" displays.   I have followed the instructions in the app to the letter.   I have copied the wiring from my two existing stats (admittedly, they're gen 2, and the new one is gen 3).  No matter what I do, I continue to get the "no power" code.

I have to say that the setup instructions are the worst I have ever seen for any product -- and I worked as an electrician at several points in my career,  a few times in theater and once for a refrigeration company.  Can anybody help me with this?

[Jaytech]

could you post a picture of your setup? Are you using a 24v common wire usually blue when you wire it? Without the common wire, many nests run into power issues.

[tbruce0]

I've now put the old thermostat back in place, but yes -- I was using a common wire (it was black, not blue).  In the last iteration, I used the same wiring I used for the other two Nest thermostats in the house (admittedly they were Gen 2), and that failed too.   I'll say again:  the setup instructions are the worst I've ever seen for any product, and I worked as an electrician for a refrigeration company for a couple of years.

[Jenelyn_O]

Hi there,

@tbruce0, thanks for reaching out and for being a step ahead of us. I'm sorry for the delay and for the trouble this may have caused you. If your Nest Thermostat isn’t detecting a wire, or there’s a power issue, you should check that the wire end is straight, fully inserted into the wire connector, and isn't corroded.

Google Nest thermostats detect wires by testing them in two ways: mechanically (is a wire inserted into the connector) and electrically (electrical current on the wire).

Try the troubleshooting steps here:

Strip and fix the wire

1. Important: Turn power to your system off at the system switch or fuse box. This helps protect your system and thermostat from possible damage.
2. Pull the thermostat display off the base. 
3. Pull out one wire and inspect it.
   • The exposed part of the wire should be ⅓ to ½ inch long, clean and straight
   • Cut and re-strip any crooked or corroded wire ends
4. Re-insert the wire.
   Important: Make sure that the wire connector’s button stays down. If not, the wire isn’t fully inserted, and the thermostat won’t detect it. 
5. Once you've checked all the wires, push the display onto the base until you hear a click.
6. Turn power to your system back on.

Please let me know how it goes.

I appreciate your input, @Jaytech.

Best,

Jenelyn

[tbruce0]

I have done all these things, including spraying everything with contact cleaner.  Nothing has worked.  I should mention that I worked as a theatrical electrician for many years, and as an electrician for a refrigeration company for a year or so.  I tried wiring the new thermostat the same way that I wired two others that I put in about four years ago (they were 2nd generation Nests, not third, but I can't imagine that would make much difference).   I have also found that the instructions given by Google are nearly impossible to follow -- in particular, the QR code in the back is too faint to pick up; I had to use a high resolution camera and then print it out in high-contrast black and white to get it to scan with my phone.  I am beginning to think that the thermostat is defective.  Is there a simple test I can perform to find out whether it is or not?  I'm about to pay a professional 300 bucks to come in and fix it and I would prefer to avoid that if at all possible.

[zoeuvre]

Hi tbruce0, 

Chiming in—could you share with us the error code that your thermostat shows, a photo of your previous thermostat wiring configuration, and a photo of how you connected the wires to the Nest Learning Thermostat base? I'll look forward to your response.

I appreciate your help,  and Jenelyn. 

Thanks,

Zoe