3 Nest thermostats stopped working

[AC9]

I have three Gen3 Nest thermostats that have been working perfectly for the past 4+ years. However all 3 stopped cooling at the same time this afternoon. Sensor screen is turned on blue on all as if “cooling” and all fans are blowing but none of the compressors turn on (forced air system). The house has steadily become hotter due to the lack of cooling. Batteries are not low. Wifi is working (I can change set temperatures on all from the app).

Any suggestions? It’d be so statistically odd that all capacitors on the HVAC would give out simultaneously.

thanks all in advance 

[AxelD]

Hi AC9,

Thanks for posting and sorry to hear about this situation with your Nest thermostat. No worries, help is here! Based on the post's information, there seems to be an issue with your HVAC system, because all three aren't working. Most of the time when only one is not cooling, the thermostat is the issue but in this case, any is working. Here you have an article Troubleshoot strange heating or cooling behavior with some troubleshooting steps that you can try. But, my recommendation is to check your system or contact an HVAC technician to do it. 

Regards,

Axel.