topic Re: Nest 3rd generation won’t switch to heat in Nest Thermostats

Nest 3rd generation won’t switch to heat

Butterflycl — Mon, 07 Apr 2025 20:21:01 GMT

Hi, I’m hoping someone can help. I have two nests, the one that runs the bigger unit will not switch back over to heat from air-conditioning. The one that runs the smaller unit won’t switch back from heat to air conditioning. All the wiring looks fine. This has happened before. this time I can’t figure out how to fix it. thank you!

Re: Nest 3rd generation won’t switch to heat

Butterflycl — Mon, 07 Apr 2025 20:30:39 GMT

Also, when I do a test it directs me to the nest website and “T04 forced air system problem”

Re: Nest 3rd generation won’t switch to heat

lucasdemon7 — Mon, 07 Apr 2025 20:49:55 GMT

It is like a frustrating issue! If everything looks good wiring wise, it might be worth checking the settings in the app or resetting the Nest thermostats Board Results 2025. Sometimes a software update or a reset can help them sync properly. If that doesn't work, double check the system’s power and make sure the HVAC units themselves are functioning as expected.

Re: Nest 3rd generation won’t switch to heat

Patrick_Caezza — Tue, 08 Apr 2025 01:49:03 GMT

@Butterflycl

You said you have two Nests. Are the units they control separate or one unit with a zone controller?

Re: Nest 3rd generation won’t switch to heat

carl310 — Tue, 08 Apr 2025 04:44:34 GMT

Just curious, has your thermostat updated recently? I've been experiencing issues for the last 2 hours since mine updated to the 6.3-5 update.

Re: Nest 3rd generation won’t switch to heat

Butterflycl — Tue, 08 Apr 2025 20:08:04 GMT

@Patrick_Caezza We have two units

Re: Nest 3rd generation won’t switch to heat

Butterflycl — Tue, 08 Apr 2025 20:11:52 GMT

Yes actually, it auto updated. @Carl310

Re: Nest 3rd generation won’t switch to heat

Djm2 — Thu, 10 Apr 2025 13:31:28 GMT

I think it might be caused by the lasted nest thermostat software update. The new update bricked my thermostat and now I am not able to use it. It’s stuck in an update loop.

Re: Nest 3rd generation won’t switch to heat

DeboraJ — Sat, 12 Apr 2025 04:44:05 GMT

Hi @Butterflycl,

Thanks for contacting the community. I understand you're experiencing an issue with your thermostats not switching back from heat to air conditioning. I'm here to help, so let's see what we can do.

To make sure I understand everything correctly, could you please provide me with the following information:

You mention that this issue happened to you in the past. Could you please tell me what steps you tried to make it work?
Could you tell me what type of HVAC system you have for both of them?
Could you please be able to send us a photo of the wiring setup for both thermostats?

Once I have this information, I'll be happy to help you to get your thermostats working on heat!

Best regards,

Debora