Nest Learning Gen 3 Early on turns on before Max duration

[mellow]

I have an issues like this one https://www.googlenestcommunity.com/t5/Nest-Thermostats/Preheating-far-to-early/m-p/312230/thread-id... .

I have 'True Radiant' setting turned on with max. duration of 2 hours. But the heating has just turned on 2.5 hours before the scheduled on time (or maybe earlier. I cannot see a record of when it actually comes on or goes off). The setting 'Auto-Schedule' says On and Learning so maybe that is something to do with it. The additional web information says "You can also choose Max Duration to limit how early your system can start preheating at night.". I am not sure what the contion "your system can start preheating at night" means. Is this feature only a nighttime feature so it won't apply to the afternoon? If so what defines "at night"?

[RenzJ · Accepted solution]

Hi mellow,

Thanks for bringing this up here in the Google Nest community. Sorry for the confusion. Changing True Radiant’s Max Duration setting will only affect preheating during the night (specifically after 8 PM), since it’s designed to keep you from being woken up too early by a noisy system turning on. Your thermostat will learn around what time you get up in the morning, and will use your Max Duration to limit how early your system turns on before then.

Let us know if you have any other questions.

Best,

Renz