Nest Learning Thermostat and Xfinity Wifi

[mbs1]

I have two Nest thermostats in my second home.  They continue to drop from the Wifi.  It is a new X1Modem from Xfinity, I have had a year.  The dropping started with the new modem.  I know there is not a static IP on this modem so I am thinking the Nest needs to be 'woken up' for it to broadcast.  Since I am not there no one walks by it.  When a friends is there it works so it has nothing to do with my app or my phone.  I believe it is the Xfinity modem broadcast.   Can't get a resolution with Xfinity.  

I do this every time I am at the home:

1.) Remove your thermostat from the Nest app. Tap your thermostat on the Nest app home screen, then tap Settings. Scroll down and select Remove thermostat.
2.) On your thermostat, go to Settings and then Reset and then WWN Connection.
3.) Select Reset and confirm that you want to reset. Your thermostat will restart.
4.) Go to Settings and then Network and reconnect your thermostat to Wi-Fi
5.) Go to Settings and then Nest app and get the entry key.
6.) Start the Nest thermostat installation flow again. On the Nest app home screen tap Settings and then Add product. Choose your thermostat and select Already installed to skip ahead to the entry key step. Type in the entry key you see on the thermostat screen.

and it works again for a few days.  Sometimes it does reconnect on its own, but mostly not.

Any other suggestions on how to 'wake it up'?  I have a timer on a light in one of the rooms that goes off at night but the Nest doesn't seem to register that.  

Is it because the nest sits dormant?  HELP please.  I'm reach on ideas. 

The product works great, I just can't control it from home to ensure the place is heating and can turn it up when it is 10 below zero.

[TechJanitor]

Xfinity automatically uses both  2.4Ghz and 5Ghz. Some Nest products only work with 2.4Ghz. I didn’t see your make/model in the post.

To change this Xfinity behavior, you can go to the Xfinity app, click WiFi at the bottom, click WiFi details in the middle of the page, click Edit WiFi Settings, then select Split Bandwidth. You will have to create different names for the 2.4 and 5 access points with their own passwords. When you connect the thermostat you can now chose the 2.4Ghz network SSID. 

Please note: If you are using Xfinity extenders you cannot split bandwidth. You will have to remove the extenders before you can complete the steps above.

[mbs1]

Thank you so much for your suggestions.

Both thermostats are: Model Nest learning thermostat, 3rd generation.  I have my wifi setup on the nest for the 5 GHZ bandwidth name and password.   I do not have extenders.   I just did a wifi check from the Xfinity app and both thermostats are connected to the wifi with a strong connection.  The 3rd generation does utilize both 2.4 and 5 GHZ.  So its not my connection.  

I'm still curious about the 'wake up' or, as they call it Farsight on the Nest. 

Like I mentioned when someone is in the unit and walks by the nest it then connects to my app.

I will also try removing the ECO and the home and away assist (I do not think I have the home away on) 

I hope to be at that home next week.

Thank you again