Solved: Nest Noticed Your Furnace Shuts Down Within 15 Minutes of Heating

Having a smart thermostat isn’t just smart for spending less on heating expenses. It can also alert you if there’s an issue with your furnace.

The Google Nest is equipped with a function called Furnace Heads Up, which will let you know if it senses an issue with your heating system. You’ll notice the warning on the thermostat, in the app and in your monthly Nest Home report.

One of the most frequent problems is: “Nest noticed that your furnace shuts down within 15 minutes of heating.” Here’s what's doing on and how you can fix it.

Your Furnace is Short Cycling

When you get the message “Nest noticed that your furnace shuts down within 15 minutes of heating,” it's saying your furnace is short cycling. Short cycling is when the furnace turns on for a short period of time then switches off. This HVAC game of red light, green light prevents your home from heating up and can increase your energy bill. It can also increase wear and tear on your furnace. It may also be more susceptible to breaking down and may even require replacement more quickly.

Without Furnace Heads Up, you might not detect your furnace is turning on and off frequently, because its blower fan might keep running. This feature can detect power interruptions that happen during short cycling.

How Do I Keep My Furnace from Short Cycling?

There are a few easy ways you can prevent your furnace from short cycling.

Replace Your Air Filter Often

If your air filter is too dirty, it will limit airflow. Your furnace will then shut down early to prevent overheating. We encourage changing flat filters once a month, and pleated filters every three months. It’s easy to stay on top of changing your filter by adding a Filter Reminder on your thermostat.

If you’ve replaced your filter after receiving a Furnace Heads Up alert, you can do a test to see if that fixes the problem.

  • Press the ring to pull up the Quick View menu, where you’ll select "settings" and then "equipment."
  • The thermostat will show the wires connected to it. Choose "continue."
  • You’ll see system components displayed. Hit "test."
  • Select "Furnace Heads Up" and follow the instructions. Your furnace will run a 15-minute heating check and tell you the results when it’s finished.

Google says if the filter is clean or if your furnace didn’t clear the test, something else could be wrong that needs professional help. If this happens, contact Service Experts Heating & Air Conditioning at 330-235-1260 for furnace repair.

Clean or Replace Your Furnace’s Flame Sensor

Having a dirty or malfunctioning flame sensor is another top explanation why your furnace might short cycle. You can tell if there’s a problem by watching your furnace as it starts up. Here’s what to look for.

  • Take off the door from your furnace so you can look at the burners. If you have a viewport in the furnace door, you may not need to remove the door for this.
  • Switch on the furnace by setting the thermostat to a warmer indoor temperature.
  • When you switch on the heat, the fan will begin running first. You should notice it turn on.
  • The ignitor will begin to glow. The ignitor is either on the left or right of the burners, but it depends on the furnace model.
  • Once the ignitor is hot enough, the gas will switch on and the burners will light.
  • If the flame sensor can’t sense a flame, it’s usually because it’s dirty or faulty. Your furnace will then turn off as a safety measure. If your furnace is short cycling, you'll notice the flame and fan shutting down after a few seconds.

If you’re questioning how flame sensors could get dirty being bathed in fire continuously, a blend of moisture and chemicals in the air form a thin coating of carbon on the surface. Cleaning a dirty flame sensor will stop the short cycling problem. This job is best left to an Expert. That's because an HVAC professional like Service Experts Heating & Air Conditioning will be able to clean it without breaking it or be able to tell you if it needs to be replaced.

Check Your Furnace’s Exhaust Pipe Often

Your high-efficiency furnace vents combustion gases outdoors through a PVC pipe. This pipe can get blocked by snow or bird nests, so you’ll want to ensure that it’s always clear. If the pipe gets clogged, it can cause your furnace to overheat. It could also result in carbon monoxide flowing back into your home, creating a potentially life-threatening situation.

However, modern furnaces are equipped with a pressure switch that generally will stop these situations from occurring. Households with small children will often find their kids have jammed toy cars, sticks or nuts into the exhaust if it’s in an area that's accessible by tiny hands. Even this little amount is enough to trigger the pressure switch. The irregular flow of air into and out of the system trips the pressure switch, which shuts off the burners. If this is the underlying cause of your problem, you will encounter short cycling and a furnace error code indicating the pressure switch was triggered.

An Expert HVAC technician from Service Experts Heating & Air Conditioning can look up the codes for you and diagnose the problem. Unfortunately, Nest has not evolved to the point where it can interpret the error codes furnace manufacturers produce, so you will still require a pro to assist you.

Let the Experts Handle Your Short Cycling Furnace

If you get the message, “Nest noticed that your furnace shuts down within 15 minutes of heating,” you know what to do. At Service Experts Heating & Air Conditioning, our Experts have the knowledge to fix any furnace problem quickly and affordably. What’s even better is that we stand behind our repairs with a 100% Satisfaction Guarantee for one year.* To book your appointment, call us at 330-235-1260 or schedule online.


*Not applicable to the Advantage Program. See your signed Advantage Program Agreement for full details and exclusions. 100% Satisfaction Guarantee is subject to certain restrictions and limitations as set forth in the applicable Terms and Conditions.