Thermostat in Cool Mode, but heat came on not the weather became cool

[jvolkers]

My config is on Cool only, but with the recent cooler weather the thermostat triggered the heater to run.    Ideas on troubleshooting to prevent this?

[Derickf]

Hi @jvolkers,

I appreciate you taking the time to post in the community. I’m sorry to hear that you are having issues with the thermostat; I'll be more than glad to help you.

To assist you better, I need more information about the Nest Thermostat you have: 

1. What type of thermostat do you have? 
2. Have you checked if the thermostat has a schedule?
3. Have you checked if the safety temperature is activated on your thermostat?

In the meantime you can take a look at the following article: Thermostat Safety Temperatures.

I’ll be waiting for your reply.

Regards,

Derick.