Nest Thermostat Cooling & Firmware

[goniners81]

My upstairs (heat pump) HVAC system has been working correctly since installation in mid-2022. Last week, it stopped cooling. I had a technician come out to check the system, and he said that the thermostat was no longer sending the cooling signal to the system, so the compressor was sending heat. He checked the wiring and determined that the Thermostat wasn't sending the proper voltage, even when switching to another spare wire in the wall. He swapped the Nest Thermostat with the old non-smart thermostat I had lying around, and that worked fine with existing wiring.

My question is - I noticed before the swap that the Nest Thermostat had been upgraded to version 2.2-6. I haven't seen any documentation of that software update, and the timing seems suspect. I have another Nest Thermostat for my downstairs system that's still on the published version of 1.3-10, but I'm worried that when it gets the upgrade I'll see similar issues with performance for that unit. Does anyone know about this new version? Is there any way to get my Nest Thermostat working again, or should I stick with the non-smart version?

[GabrielaG]

Hi @goniners81,

Thanks for reaching out to the community. I'm sorry to hear your Nest Learning Thermostat isn't working as expected and is no longer sending the cooling signal. No need to worry; I'd be glad to help.

I appreciate your efforts with the technician trying to solve the problem. To give you the best information, I have a few questions:

• What type of Nest Thermostat do you have? 
• Is this the first time you're calling for cooling this year? If yes, did heating work without issues in the winter?
• Have you checked the O/B wire configuration and tried changing the O-wire to B-wire configuration or vice versa?
• Did you try swapping the O/B and G wires on the Nest terminals, then testing for cooling and heating?
• Have you experienced extremely hot weather lately?
• Do you see a power error code on your thermostat?
• Have you set up a temperature schedule for your thermostat?

I look forward to your response.

Best regards,

Gabriela

[goniners81]

1. Nest Thermostat (2020), not one of the Learning ones.
2. No, it had been successfully cooling for months this year, and for several years before that. Heat worked as expected over the winter.
3. The O/B wire configuration was checked and swapped, but that didn't help.
4. The technician swapped that wire with a spare wire to check if it was a wiring problem, and the spare wire exhibited the same behavior where the thermostat was not sending the cooling signal.
5. It's been hot, but it wasn't the hottest day of the year when I started seeing the issues. Swapping to the other non-smart thermostat solved the issue on that same hot day.
6. No error codes.
7. Yes, there was a schedule configured on the Nest thermostat. 

[GabrielaG]

Hi @goniners81,

Thank you for your reply. I appreciate your quick response and the information you provided me. I'm glad to share more details with you.

The team would like to know more about this behavior. When you get a chance, please fill out this form . Remember to include the link to this post. Let me know when you’re finished. From there, we'll contact you via email. 

Let me know when you're finished. Your confirmation is crucial to ensuring that I can follow up on your case effectively.

Regards,

Gabriela

[goniners81]

That link is broken and says "Sorry, this page can't be found." Also, the URL refers to the Pixel Watch. Can you send an updated link? Thanks!

[GabrielaG]

Hi @goniners81,

Thank you for your reply. I'm sorry the link I sent was broken, and I appreciate you letting me know about that problem.

When you get a chance, please fill out this form so we can learn more about this behavior. Remember to include the link to this post in the form.

Please let me know once you've finished filling out the form. Your confirmation is crucial for me to follow up on your case effectively, and we'll contact you via email after that.

Let me know if you have any questions.

Regards,

Gabriela

[OmBheemBush]

Have you gotten this issue fixed. I have the exact same problem.

[goniners81]

No, there wasn’t a solution identified. I’m still using the non-smart thermostat to control the HVAC.

[markm74]

I also noticed 1 of my 5 Nest Thermostats have been upgraded to 2.2-6 but cooling is working just fine.  One thing I did notice was that I can now turn on the fan without having to set a heat or cool mode which is great!!

[markm74]

I am yet to see any release notes on firmware 2.2-6 though.