topic Re: Notification of Heating System Failure in Nest Thermostats

Notification of Heating System Failure

Molly6 — Thu, 05 Feb 2026 15:13:24 GMT

Due to a problem with my propane furnace, the thermostat is calling for continual heat but the room temperature has dropped significantly below the temperature setting. When heating time spikes and the room temperature is much lower than the setting, why doesn’t this trigger a notification??

Re: Notification of Heating System Failure

TEEBE — Thu, 05 Feb 2026 18:40:02 GMT

I have had this identical problem in the last several weeks.

Re: Notification of Heating System Failure

jasonmarie8 — Mon, 09 Feb 2026 00:50:46 GMT

That’s a fair question those conditions seem like exactly what an alert should catch, especially to prevent damage or discomfort. Smart systems should flag anomalies early.

Re: Notification of Heating System Failure

Patrick_Caezza — Sat, 07 Feb 2026 05:06:52 GMT

@jasonmarie8

Please do not include unrelated off-site links in your posts. Doing so will result in your getting banned as a spammer.

Re: Notification of Heating System Failure

AshleyB — Mon, 09 Feb 2026 01:48:40 GMT

Hi there,

Thank you for posting in the community. I’m sorry to hear that your Nest Thermostat does not trigger a notification when your room temperature drops significantly below the set point during a furnace issue. I'm here to help!

To assist you further, could you please let me know:

What model of Nest Thermostat do you have? Here’s a helpful article about how to identify your thermostat model.
Do you have additional Nest Thermostats? If so, are they experiencing the same issue?
Have you tried any troubleshooting steps before contacting us?

@jasonmarie8 and @Patrick_Caezza, thanks for jumping in on this!

Keep me posted; I'll be waiting for your response.

Best regards,

Ashley

Re: Notification of Heating System Failure

Molly6 — Mon, 09 Feb 2026 18:51:59 GMT

model: Nest Learning Thermostat 4th gen

No other Nest thermostats in the house with the furnace problem.

I posted in the community after thoroughly checking settings options in Google home.

Re: Notification of Heating System Failure

TEEBE — Mon, 09 Feb 2026 19:46:35 GMT

I have a 4th generation, just like Molly. I also explored if it was a settings problem before I saw Molly's post.

Re: Notification of Heating System Failure

AshleyB — Tue, 10 Feb 2026 05:28:29 GMT

Hi folks,

Thanks for replying; I appreciate the information you shared. It will be necessary to follow some troubleshooting steps to resolve the issue.

First, let's try removing the Y1 wire to see if the system short cycles. Follow these steps to do so:

At the breaker box, turn off the power to the HVAC system.
Remove the Y1 wire, cover the metallic end with electrical tape or a wire cap, and tuck it into the wall.
Turn the power back on at the breaker box.
Call for heat (set the thermostat to heat mode) and check if the system activates. Some systems take time to start, so please wait up to 5 minutes.
If the heat works, you can leave the Y1 wire disconnected temporarily to continue generating heat.

After removing the Y1 wire, please move the W1 wire to the Y1 terminal. Please follow these steps:

At the breaker box, turn off the power to the HVAC system again.
Move the W1 wire to the Y1 terminal, then put the display back on the wall.
Turn the power back on at the breaker box.
Switch to Cool mode (note: you should expect heat to come out).
Check if the system runs. Again, it may take up to 5 minutes for the heat to activate.

Please let me know if the issue persists after following these steps.

Best regards,

Ashley

Re: Notification of Heating System Failure

Molly6 — Tue, 10 Feb 2026 17:41:20 GMT

I’m a bit confused. These troubleshooting steps are to resolve a system failure notification issue? The thermostat appeared to be working correctly but my furnace was not supplying heat. Thanks.

Re: Notification of Heating System Failure

TEEBE — Tue, 10 Feb 2026 18:06:48 GMT

I'm confused too. I have had up to 5 hours with the thermostat calling for heat and the temperature dropping. That should be enough time to send a notification that something is wrong. The furnace control board had faulted because of lack of combustion due to a sticky solenoid on the gas valve. As with you, the thermostat did everything correctly except for the sending a notification of the furnace not working.

There is so much more that this thermostat could do if you gave the user more control. I have tried the script writing, but it is so limited.

Re: Notification of Heating System Failure

AshleyB — Wed, 11 Feb 2026 01:22:33 GMT

Hi folks,

Thank you for your response. I would appreciate it if you could perform the troubleshooting steps mentioned above, as this may help solve the problem you are having with the heating system failure notification you are receiving. These steps will also help me determine if the issue is with the thermostat itself or with your furnace.

Keep me posted; I'll be waiting for your response.

Best regards,

Ashley

Re: Notification of Heating System Failure

TEEBE — Wed, 11 Feb 2026 14:51:25 GMT

As mentioned before, I cannot perform the troubleshooting steps due to the specifics listed above. This is a thermostat software problem, not a furnace problem.

Re: Notification of Heating System Failure

aaliyamalikk — Sat, 14 Feb 2026 07:12:26 GMT

I share your confusion. I have experienced instances where the thermostat has been calling for heat for as long as 5 hours, yet the temperature continues to decline. This duration should suffice for a notification to be issued indicating that an issue exists. The control board of the furnace malfunctioned due to insufficient combustion, which was caused by a sticky solenoid on the gas valve. Similar to your experience, the thermostat performed all functions correctly, except for notifying us that the furnace was inoperative.

Re: Notification of Heating System Failure

TEEBE — Mon, 16 Feb 2026 14:18:32 GMT

This issue should have been fixed quickly, the fact that it hasn't been shows a lack of commitment to this product IMO.