Reset Time-to-Temp (2023)

[geoffschultz]

I have been unable to find any answers within this forum on how to reset the Time-To-Temp calculation on my 3rd generation Nest thermostats. I have thermostats, all of which were installed last year, and all of which have the same problem.

I have placed a data-logging thermocouple on my furnace zones, and I am also logging temps in rooms so I can see exactly when things turn on and how fast the heat rise is.

I have a schedule set up on them which turns the heat down to 60F at night and then is supposed to bring it to 68F by 6 AM.

Time-to-Temp is "ready", and True Radiant (I have hydronic heat) is on with a 2-hour max pre-heat.  Based upon these settings, I would expect the heat to come on at 4 AM at the earliest and be at 68 at 6 AM. Nothing could be further from reality.

Yesterday, the heat came on at 04:56 at was at 62F at 06:00.  It didn't reach 68F until 08:20 and then overshot to 70F at 9:05

Clearly, something is very wrong with the calculation.  I'm hoping that I can reset the thermostat and have it recalculate this. Either that, or I'll swap these thermostats out with something that works.

-- Geoff

[zoeuvre]

Hi geoffschultz, 

Yikes! Let's sort this out. The Time-to-Temp calculation on a Nest Thermostat is not user-configurable, but it learns the heating system's time to reach the desired temperature and adjusts its behavior by monitoring and analyzing data over time. Time-to-Temp feature relies on machine learning algorithms and data analysis, so it may take some time for the thermostat to adapt and optimize its behavior based on your specific heating system and usage patterns.

Here are few steps you can take to troubleshoot inaccurate or inconsistent Time-to-Temp calculations: 

1. The Nest Thermostat should be installed in a suitable location, away from direct heat sources, drafts, and poor airflow areas, to ensure accurate temperature readings and HVAC system control.
2. Ensure that there are no obstructions and that the temperature sensors on your Nest thermostat are clean. Clean temperature sensors are essential to maintain accuracy.
3. Double-check schedules and settings to align with desired temperature preferences.
4. If temporary software issues persist, restart the thermostat by disconnecting power and reconnecting it.

Let us know how it goes.

Best,

Zoe 

[geoffschultz]

Zoe, thank you for your suggestions.

1. The thermostats are well away from everything that you mentioned.
2. There are no obstructions. The temperature readings that the thermostats show are within a degree of what my data-logging thermocouples are reading.
3. I have been through my schedules many times, and they are correct.
4. I'm not sure how to achieve this.  If I unplug the thermostat from the base plate, it shows a message that I need to reattach it.  Clearly, it's still powered up.

-- Geoff

[zoeuvre]

Hi there,

Thanks for getting back to us, and I'm sorry for the delayed response. Kindly restart your thermostat either by pressing and holding the thermostat display for 10 seconds to allow it to restart or turn off, then turn back on the power to your thermostat at the breaker box.

Regards,

Zoe