@Nkol7 

When it comes to interaction between device and WiFi mesh, the final decision where to connect belongs to device. WiFi mesh will present all its nodes and may recommend which node to connect to, but it is device that decides.

So, the right question would be "Why Nest termostat ignores nearby Deco?" 

In general, it does not matter much where thermostat connects, as it is low WiFi traffic device. Security cameras and devices such as Ring Doorbell are more problematic, as they need good connection for steady video streaming over WiFi.

I have ecobee smart thermostat, while it usually connects to nearby Deco, sometimes it starts jumping between different Deco I have at my house. It is a bit annoying, but does not impact its functionality.

Having said that, there may be ways to convince device connect to nearby Deco. There is no guarantee it'll work, but if you want to try that, let's do it.

To figure what options are available, please tell the following:

1. Does your model of Nest thermostat support WiFi 5, or is it older model that only runs on 2.4GHz?

2. Is it connected to Main, Guest or IoT WiFi network?

3. Have you made changes to default Deco mesh settings such as Fast Roaming, Beamforming?

4. Please open info page of Nest thermostat in Deco app, make its screenshot and share here.

  @Alexandre. Thanks for your response sir. 

1. Does your model of Nest thermostat support WiFi 5, or is it older model that only runs on 2.4GHz?

Not sure how to check, but as its about 2.5 years old and it is referred to as: 'Display 3.6 / Backplate 6.5' 

2. Is it connected to Main, Guest or IoT WiFi network?

My 'Main' network is in 5Ghz only mode, while my guest network is auto. Don't ask me why I did this, but I've been through so many issues and found this set up to be the most fruitful.. 

3. Have you made changes to default Deco mesh settings such as Fast Roaming, Beamforming?

Fast roaming was off, but beamforming was on - not sure why, or what it is.. 

4. Please open info page of Nest thermostat in Deco app, make its screenshot and share here.

Attached 

  @Nkol7 

This is what I can tell from the screenshot you provided:

1. Your Nest thermostat does support WiFi 5.

2. It is connected to Guest network.

If you check Fast Roaming description in Deco app, you'll see the following text there: "Fast roaming ... allows wireless devices to switch connection to different Decos seamlessly." 

You see an issue with Nest thermostat not switching connection to nearby Deco. I would suggest to enable Fast Roaming, and after that bounce thermostat. That may or may not help, but this option should be on.

There is one more option available to convince device connect to a specific Deco unit, but this option does not exist for devices on Guest network. You will need to connect Nest thermostat to Main network. Your Main Network is 5GHz only you said, and because from screenshot I can tell Nest can also use 5GHz, you should be able to connect it to Main network without any problems.

Let me know when you've done that, share new screenshot of Nest, it'll have "Connection Preference" line added there, and I'll tell you how to use connection preference feature your Nest thermostat now has.

  @Alexandre. 

Thanks for the reply. How do I manually connect a device (Nest) thermostat to a specific Deco though? Ie. "Main"? 

Nkol7 wrote

  @Alexandre. 

 

Thanks for the reply. How do I manually connect a device (Nest) thermostat to a specific Deco though? Ie. "Main"? 

  @Nkol7 

After you configure Nest thermostat to connect to Main network SSID, the option will appear to connect Nest to a specific Deco, and I'll explain to you how to use that option.

As long as Nest thermostat is connected to Guest network SSID, that option will not be available for it.

  @Alexandre. 

Hi - so, I followed your advice and connected my Nest thermostat to my "Main" network (NOT my "Guest" one), and interestingly, the Nest thermostat immediately reconnected itself to the closest Deco (the bedroom one), whilst still in "Auto" mode, and without my needing to manually specify. 

So, something about switching it to the "Main" network either refreshed the connection preferences cache (if that's a thing), or  something about this SSID made the thermostat think that the bedroom Deco (the closet one) to be more favourable. 

Thanks for your help! 

  @Nkol7 

Good news, indeed. It may be what you think that forced Nest to nearby Deco, or maybe just the fact your Main Network is 5GHz only and that helps. In cases when device does not want to connect to nearby Deco I always ask if it supports 5GHz and if does, recommend putting it on 5GHz only network. Which you happened to have as your Main Network.

  @Alexandre. 

Sorry to confuse you and introduce new variables, but yesterday, I changed the "Main" network to be both 2.4 and 5Ghz from 5Ghz only, before switching the thermostat over to "Main". But yeah, I guess, it'#s still possible that this change in variable made the thermostat play more nicely with the Deco closest to it.

  @Nkol7 

Then, I would recommend to use Connection Preference feature to configure Nest connect on 5GHz exclusively and to specific Deco. Just in case.