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

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

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

One of the most typical issues 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,” that means your furnace is short cycling. Short cycling is when the furnace turns on for a short period of time then turns 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 notice your furnace is turning on and off often, because its blower fan might keep going. This feature can pick up on power interruptions that take place 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.

Change Your Air Filter Often

If your air filter is too dirty, it will limit airflow. Your furnace will then shut off prematurely to avoid 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 changed your filter after receiving a Furnace Heads Up alert, you can do a test to see if that repairs the problem.

  • Push the ring to bring up the Quick View menu, where you’ll choose "settings" and then "equipment."
  • The thermostat will display the wires linked to it. Choose "continue."
  • You’ll see system components shown. Select "test."
  • Choose "Furnace Heads Up" and follow the instructions. Your furnace will run a 15-minute heating check and tell you the results when it’s done.

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 McElroy Service Experts at 308-210-4398 for furnace repair.

Clean or Replace Your Furnace’s Flame Sensor

Having a dirty or bad flame sensor is another top reason 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 higher indoor temperature.
  • When you turn on the heat, the fan will turn on first. You should hear it turn on.
  • The ignitor will begin to glow. The ignitor is either on the left or right of the burners, but it varies according to the furnace model.
  • Once the ignitor is hot enough, the gas will turn on and the burners will ignite.
  • If the flame sensor can’t detect a flame, it’s usually because it’s dirty or defective. Your furnace will then turn off as a safety measure. If your furnace is short cycling, you'll notice the flame and fan shutting off after a few seconds.

If you’re wondering how flame sensors could get dirty being bathed in fire constantly, a blend of moisture and chemicals in the air form a thin layer of carbon on the surface. Cleaning a dirty flame sensor will end the short cycling problem. This job is best left to an Expert. That's due to the fact an HVAC professional like McElroy Service Experts will be able to clean it without damaging it or be able to tell you if you need a new one.

Check Your Furnace’s Exhaust Pipe Frequently

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

However, modern furnaces are equipped with a pressure switch that typically will prevent these situations from happening. Families with young children will often find their kids have stuffed toy cars, sticks or nuts into the exhaust if it’s in an area that can be reached by little hands. Even this small amount is enough to trigger the pressure switch. The uneven flow of air into and out of the system triggers the pressure switch, which shuts down the burners. If this is the root of your problem, you will experience short cycling and a furnace error code indicating the pressure switch was triggered.

An Expert HVAC technician from McElroy Service Experts can check the codes for you and diagnose the problem. Unfortunately, Nest has not developed to the point where it can interpret the error codes furnace manufacturers create, so you will still require a pro to help you out.

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 McElroy Service Experts, our Experts have the knowledge to resolve 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 308-210-4398 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.

Contact Us