Nest Learning Thermostat turns itself OFF Mode

[jjrubin]

Same problem as described in multiple threads, best match is https://www.googlenestcommunity.com/t5/Nest-Thermostats/Nest-randomly-turning-off/m-p/604796

I'm positive Auto-Scheduling and Home/Away and Eco all turned off. My system uses AirZone adapter to let Nest work with Misubishi heat pump. Power is hardwired so battery not an issue.

I'm seeing other anomalies: Heat still running when indicated room temp is 5 degress above the thermostat setting; Setting the heat to 60 degrees changes to 63 within seconds. Weird.

My service tech is coming out to resolve (and brining a new unit if needed). 

[JuanCH]

Hi jjrubin,

Thanks for reaching out to the community! I understand that even with Auto-Scheduling, Home/Away Assist, and Eco mode all switched off, and with your Nest thermostat device connected to your Mitsubishi heat pump via an AirZone adapter with a direct power connection, you're still seeing some unusual activity. Specifically, the heat continues to run even when the room is significantly warmer than the set temperature. I know how difficult it is when a device doesn't work as expected. I'll be glad to help you with this. To gather some more details, I'd like to ask the following questions:

• What's your Nest thermostat device model? Please check out the following link for your reference: How to tell which Nest thermostat you have
• Did you recently turn off any breakers?
• Is your Nest thermostat device newly installed?

Please keep me posted. I look forward to your response.

Best regards,
Juan

[jjrubin]

Third-gen Nest Learning. Just installed (replacing the previous new unit which had several anomalies and promted this post originally). Turned by itself from Heat Mode to OFF Mode. Settings:  Auto-Scheduling -- Off, Home-Away -- Off, all settings in the most basic manual mode available. I observed this behavior just once in the first night after installation. Since then it has gone more than 24 hours without turning itself OFF.

[jjrubin]

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@jjrubin wrote:

Same problem as described in multiple threads, best match is https://www.googlenestcommunity.com/t5/Nest-Thermostats/Nest-randomly-turning-off/m-p/604796

I'm positive Auto-Scheduling and Home/Away and Eco all turned off. My system uses AirZone adapter to let Nest work with Misubishi heat pump. Power is hardwired so battery not an issue.

I'm seeing other anomalies: Heat still running when indicated room temp is 5 degress above the thermostat setting; Setting the heat to 60 degrees changes to 63 within seconds. Weird.

My service tech is coming out to resolve (and brining a new unit if needed). 

---

Since I've been deep into this trouble-shooting with my service tech who installed the system (and he also had 2nd level Nest support on the phone), what would help most at this point is for you to list all known potential causes for a Nest Learning Gen3 to turn itself from Heat Mode to OFF Mode. Then we can check to see if any of those apply here, either in Settings or the installation incl. AirZone interface.

[JuanCH]

Hi jjrubin,

Thanks for following up! I understand that your Nest Learning Thermostat Gen 3 switched itself from Heat to Off once, right after installation. Since then, it has gone more than 24 hours without turning itself off. You've already been working with your installer and Nest support. I'm glad to help!

To get started on exploring potential causes, could you share your case reference number with me? That way, I can take a look at any notes that might already be on file.

Keep me posted. I look forward to your response.

Best regards,
Juan

[jjrubin]

I don't have a case number as my service tech had that call. However the most complete and current information is contained in this thread with GROK (AI) on our issue. It's long so please skip to the bottom to 'Quick Recap For Your Tech' and 'Notes For Your Tech'. https://x.com/i/grok/share/UWAAvcYurcv0ccOK1FC7aqqRM

https://x.com/i/grok/share/UWAAvcYurcv0ccOK1FC7aqqRM