Troubleshoot Furnace Heads-Up

Furnace Heads-Up can let you know when your Google Nest thermostat has detected a problem with your forced air heating system. To troubleshoot, you should run a quick system test to confirm there’s an issue.

If your Nest thermostat detects that your furnace hasn’t been able to heat for longer than 15 minutes at a time, you’ll get a Furnace Heads-Up message on your Nest thermostat, in the Nest or Home app, and in your Nest Home Report. 

The message on the thermostat will say, “Nest noticed that your furnace shuts down within 15 minutes of heating” and you’ll be given a link to this troubleshooting article and the option to dismiss the alert.

The Heads-Up will only appear on your thermostat and in the app once each time it detects an issue. You’ll get a Heads-Up in your Nest Home Report each month there’s a potential problem.

1. Check your system’s air filter

A clogged filter is one of the most likely reasons a furnace might shut itself off. If your filter looks OK, skip to step 3. Remember, you can also set up Filter Reminders that will let you know when it’s time to change your filter. Check the following article for detailed instructions.

Air filters and filter reminders

2. Test to check if the air filter fixed the issue

If you get a Furnace Heads-Up alert, there will be a new option for Furnace Heads-Up testing in the thermostat's System Test menu.

  1. Press the thermostat ring to bring up the Quick View menu.
  2. Choose Settings Equipment.
  3. You’ll find the wires you have connected to your thermostat. Choose Continue.
  4. Your system components (Heat, Fan, Cooling if you have them) will show. Select Test.
  5. Select Furnace Heads-Up and follow the onscreen instructions.
  6. Your system will run a heating test for 15 minutes, and tell you the results at the end.

Learn how to run a System Test

Note: Your Nest thermostat must be connected to Wi-Fi and the internet for the test to run. If it’s not, there will be an alert to let you know.

3. Contact a local pro for service

If your system’s air filter looks OK, or if your system didn’t pass the System Test after changing the filter, there may be other issues. Your furnace’s behavior could be caused by a clogged evaporator coil, broken fan motor, blocked air ducts or heating vents, poor gas pressure, or another issue that may require service by an HVAC professional. We recommend that you contact a local pro to service your system.

Limitations of Furnace Heads-Up

You can get Furnace Heads-Up notifications on the Nest thermostat whether or not your thermostat is connected to Wi-Fi and the internet. Furnace Heads-Up notifications in the Nest app and Home Report require your home to have a working internet service and Wi-Fi connection to your Nest thermostat. The notifications are relayed over the internet and can only work if the internet and Wi-Fi in your home are working. So if your Wi-Fi network goes down, it could adversely affect the availability and accuracy of Furnace Heads-Up.

Furnace Heads-Up is not a foolproof way to detect a problem with your forced air heating system and should not be relied upon as a way to monitor whether your heating system is working properly. These notifications are not intended to be a substitute for regular system service by an HVAC professional.

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