Defective Google Nest Thermostat

[Olsonj4]

I need some assistance. I have a three zone system where I replaced the three Honeywell thermostats with Google Nest thermostats. As many people in this forum have identified, I had the E294 error issues on all three of them. For two of them I finally was able to get them running without any error codes. The third one will continually give me this code. As everyone else has mentioned, I have factory reset the thermostat multiple times while removing the device from my Google Home App. After two days of this I decided to swap this third thermostat with one that was set up correctly. The funny thing is once I got everything setup again, the area that I was having issues with, with the other thermostat did not have any issues. However, the third thermostat that I was having problems with continues to give me the same errors in the new location (that did not have issues with the other thermostat). In fact on this problem thermostat, when I go to check the wiring on the app, there are no connections shown whatsoever (no G, Y, W or R). Is there a way that I can tell if the thermostat is defective? 

[Jenelyn_O]

Hi Olsonj4,

Thanks for reaching out and for being a step ahead of us. A few questions: in what country are you located? Are all of your Nest Thermostats the same kind? Are all of them connected to the same HVAC system? Are there other devices or appliances (such as baby monitors, microwaves, cordless phones, etc.) near your thermostats? They could be interfering with the Wi-Fi or Bluetooth signal.

Also, this issue occurs when your thermostat fails to detect an electrical signal from any of its required wires. The common reasons include the following:

• The wires aren’t fully inserted.
  The wires don’t meet the terminals, so there’s no connection. Make sure that at least ¼ to ½ inch of the copper wire is exposed, straightened, and fully inserted in each of the required connectors. You can gently pull the wires to make sure that the connection is secure.
• The wires are too small.
  The Nest Thermostat requires 18 to 22 gauge solid-core copper wires. Any diameter that’s smaller than that is too thin for the Nest Thermostat to detect, and you or a Nest Pro needs to replace it.

Best,

Jenelyn