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

Having a smart thermostat isn’t just smart for saving on heating costs. It can also let you know if there’s a problem with your furnace.

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

One of the most frequent issues is: “Nest noticed that your furnace shuts down within 15 minutes of heating.” Here’s why this is happening and how you can fix it.

Your Furnace is Short Cycling

When you see 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 stops your home from heating up and can drive up 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 running. This feature can recognize 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.

Change Your Air Filter Regularly

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

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

  • Press the ring to pull up the Quick View menu, where you’ll choose "settings" and then "equipment."
  • The thermostat will show the wires connected to it. Choose "continue."
  • You’ll see system components displayed. Select "test."
  • Choose "Furnace Heads Up" and follow the instructions. Your furnace will go through a 15-minute heating test 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 requires professional assistance. If this happens, call Gordon's Service Experts at 405-432-2197 for furnace repair.

Clean or Replace Your Furnace’s Flame Sensor

Having a dirty or malfunctioning flame sensor is another top reason why your furnace is short cycling. 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 see the burners. If you have a viewport in the furnace door, you may not have 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 warm 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 faulty. Your furnace will then shut off as a safety precaution. 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 coating of carbon on the surface. Cleaning a dirty flame sensor will stop the short cycling issue. This task is best left to an Expert. That's due to the fact an HVAC professional like Gordon's 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 Often

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

However, modern furnaces have a pressure switch that typically will prevent these situations from happening. Families with young children will often find their kids have jammed toy cars, sticks or nuts into the exhaust if it’s in a location that can be reached by little hands. Even this little amount is enough to trip the pressure switch. The irregular flow of air into and out of the system triggers the pressure switch, which shuts down 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 tripped.

An Expert HVAC technician from Gordon's Service Experts can check the codes for you and diagnose the problem. Unfortunately, Nest has not evolved to the point where it can read the error codes furnace manufacturers create, so you will still need 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 Gordon's Service Experts, 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 405-432-2197 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.

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