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Having trouble with your Honeywell smart thermostat not staying connected? This can cause annoying errors and delays, making it really hard to control from afar.

In most cases, a low Wi-Fi signal is the culprit, and eliminating Wi-Fi dead zones can resolve this.

However, that’s only one possible cause. So keep reading to learn more.

Reasons for a Honeywell Thermostat Connection Failure

Below, I’ve listed 10 of the most common reasons for a connection failure. I’ve also provided solutions and tips to prevent these issues from popping up in the future. 

1. Thermostat Not in Router Range

As I mentioned, the most probable reason why your Honeywell thermostat is suffering from connection failures is that it’s located outside your router's signal range.

So even if it may seem like a simple oversight, many people overlook this detail, especially since you can’t gauge the signal strength of the thermostat using your smartphone without advanced apps.

To determine whether this is an issue, check the distance between the router and the thermostat.

If the thermostat is situated at the edge of your router's signal range, it might be susceptible to connectivity issues due to minor disruptions, such as people passing by or interference from other smart devices and microwaves.

  • So, try relocating your Wi-Fi router to a position closer to the thermostat.
  • If that's not feasible, consider upgrading your router to one with a broader range.
  • Another option is to invest in a Wi-Fi booster or implement a mesh network, both of which can extend the signal coverage and eliminate dead zones.

When attempting to connect the thermostat to your smartphone, verify that both the app and your device's software are up to date, and hold the phone closer to the thermostat for optimal connection.

2. Thermostat Can’t Detect Wi-Fi Network

In other cases, the smart thermostat might not be able to detect your Wi-Fi network entirely.

To resolve this, first, ensure that your router is switched on. If you've recently returned from vacation and forgot to plug it back in, this will be a quick fix.

Check for the 2.4GHz Band

  • If your router is working, check if it's a 5Ghz Wi-Fi router that doesn't support the required 2.4GHz channel.
  • Many smart home devices, including thermostats, typically do not work with the 5GHz channel supported by dual routers.
  • Temporarily turning off the 5GHz band during thermostat setup can help establish the connection or configuring your router to broadcast on both 2.4Ghz and 5GHz can help.

Soft-Restart the Thermostat

If these steps don't help, try restarting your thermostat by disconnecting it from the main power or removing one of its batteries.

This action could improve the connection, especially if the network details remain the same.

Check for VPNs

Also, ensure that you disable any VPNs or spoofers, or force close their respective applications, before attempting the connection again.

3. Wi-Fi SSID hidden

Another reason could be that the Wi-Fi name is hidden from the public and other devices. Maybe you’re using additional firewalls or a computer-computer network. Either way, you can break down these digital walls with a simple solution.

All you need to do is change your router’s settings. To do that, access your router’s settings page. You can also do that from your network connection settings if your computer is connected to the Wi-Fi network. 

Another way to deal with this issue is by manually inputting the Wi-Fi name in your thermostat. You should be given an “Other” option when it comes to Wi-Fi names. Input the name of your network manually. Be careful about cases and spellings. 

4. Wi-Fi Disabled On Your Thermostat

Recent models, such as the T10 Pro, have the option to disable Wi-Fi connections. 

To enable it:

  1. Activate/Wake up the screen on your thermostat by touching any part of the display
  2. Tap on the sandwich (three horizontal lines) menu button at the bottom
  3. Scroll down and select “Wi-Fi” from the list
  4. Make sure the “Enable Wi-Fi” toggle switch is set to on 
T10 enable Wi Fi settings
Enabling Wi-Fi access to a Honeywell T10 Pro smart thermostat

5. Wi-Fi Can't Connect to the Internet

If your Wi-Fi router is unable to connect to the internet, there might be a problem with your network or ISP.

To test your connection speed, visit fast.com

Use Mobile Hotspot

If your Wi-Fi network is experiencing difficulties, consider using your phone's mobile hotspot as an alternative to connect your thermostat.

If that works and you can access the internet via your Wi-Fi, the issue might be in your Wi-Fi router. Therefore, it's essential to verify your thermostat's IP address.

Verify the Thermostat’s IP Address

  1. To do this, remove the faceplate from the wall for 30 seconds and then reconnect it.
  2. After two minutes, look for the Wi-Fi icon on the thermostat display.
  3. If there's no X symbol, the thermostat has successfully reconnected.
  4. Next, go to the thermostat’s menu screen, and open up the Wi-Fi settings/information.
  5. Here, note down the IP address.
  6. If the IP address is something like 169.254.x.x or 0.0.0.0, your thermostat is connected to the local network but isn’t provided permission to access the internet.
    1. In this case, contact your Internet Service Provider (ISP) or network support for assistance with DHCP settings.
  7. If the IP address is something along the lines of 192.168.x.x, 172.x.x.x, or 10.x.x.x, your thermostat is connected to both the DHCP service and allowed to browse the internet.

6. Wi-Fi details have changed

Do you remember making any changes to your Wi-Fi network details recently? Perhaps you changed the name or password of the network. In that case, the thermostat will not be able to recognize the new network properties.

To solve this problem, all you have to do is reconnect to the network the same way you did when you connected for the first time. Find the network, input the password, and pair the devices. 

Try Disconnecting and Reconnecting to Your Wi-Fi Network

If you need to disconnect your thermostat from your home Wi-Fi, follow these steps: 

  1. Reset the Wi-Fi settings on your thermostat. Click here for a guide on how to do this.
  2. If you’re using a newer model such as the T10 Pro and T9, simply switch to a different network or forget the old one.
  3. Then, delete the thermostat from the Honeywell Home app.

How to Change the Wi-Fi Network on T9 and T10 Models

To change the Wi-Fi network on T10 Pro, T9, and Series 9000 models: 

  1. Wake up the thermostat's display 
  2. Tap the Menu icon
  3. Scroll to Wi-Fi 
  4. Tap “Choose Network” 
  5. Select a new network or hotspot, and enter your password.
T10 Wi Fi Change 1
Changing the Wi-Fi network on a Honeywell T10 Pro

How to Remove Your Thermostat from the Honeywell Apps

To remove your thermostat from the Honeywell Home app: 

  1. Open the app 
  2. Choose your device 
  3. Tap the gear settings icon 
  4. Select “Thermostat configuration” 
  5. Press “Delete Thermostat.”
T6 Delete app
Deleting a thermostat from the Honeywell Home app

After that, you can follow the app's instructions to reconnect your device.

7. Network Interference

A crowded network is tough on your router, especially when it lacks sufficient bandwidth to handle all of your connected smart devices.

Remember, the majority of these devices rely on the 2.4GHz band, and crowding can bog down the signal.

You must also be cautious about other wireless connectivity sources that might interfere with your Wi-Fi network; this includes Bluetooth devices and even microwave ovens.

To pinpoint the issue, prioritize your network needs by disconnecting or turning off other devices before trying to connect the thermostat again.

A less congested network should enhance the connectivity process for your thermostat.

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8. Router needs a Reboot

A less common cause of thermostats disconnecting from the Wi-Fi lies in the router itself. Perhaps your router needs a reboot! Think about it, has there been a power surge in your house recently?

Maybe the router has undergone an automatic update? Could it be that some firmware bug took place? If you can say yes to any of these possibilities, it might be time to reboot your router!

The easiest way to reboot your router is by turning the power off and on again. If it doesn’t work, press and hold the reboot button for a long time to factory reset the router. That will also erase the Wi-Fi name and password that you’ve set up, which might be annoying to change. 

9. Issues with the Thermostat Specifications

First-timers setting up a thermostat connection can be tricky, so ensure you're aware of your network's specifications, such as IP address assignment, wireless security compatibility, and network types.

To find this information, you can check the box or user manual to verify that it matches your network.

10. Issues with Firmware updates

Firmware updates are essential for Honeywell Thermostats to function efficiently and maintain a reliable connection with your Wi-Fi network.

While updates typically occur over Wi-Fi without major problems, there are occasions where issues may arise.

To resolve connection failures, you should first verify if any updates are available within the Honeywell app or consider performing a factory reset on your smart thermostat.

Ensure that your Wi-Fi network operates on the 2.4GHz band, provides a strong signal for your thermostat, and maintains stable internet access throughout the process.

The Verdict

Troubleshooting Honeywell Thermostat connection issues can sometimes become very tedious. A connection failure could be related to why your Honeywell thermostat is flashing cool on.

As long as you have a strong Wi-Fi signal and you know how to access the router’s settings, you should be fine for the most part. 

That said, if you run into more issues, make sure to drop a comment and also get help from a professional. A connection failure could be a sign that you need to troubleshoot your Honeywell thermostat not working issues.

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2 Comments

  • Cherie
    Posted February 1, 2022 at 5:38 am

    I rent my home and all of a sudden my thermostat says it is not communicating with the wireless Network however I have Wi-Fi and to my knowledge it isn’t even connected to the thermostat because we have not even had Wi-Fi that long and it worked before. So what do I do to fix this problem because it is extremely cold outside and getting colder in my house by the minute?!.

    • Gorgorilla
      Posted February 13, 2022 at 4:40 pm

      Your WiFi thermostat does not need to connect to your network to operate your furnace.

      If you walk up to your thermostat and set it to 90 degrees and your heat doesn’t work, your problem is either a bad thermostat, broken wiring or bad furnace.

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