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 has a feature called Furnace Heads Up, which will alert you if it notices an issue with your heating system. You’ll notice the alert on the thermostat, in the app and in your monthly Nest Home report.

One of the most common issues is: “Nest noticed that your furnace shuts down within 15 minutes of heating.” Here’s what's doing on and how you can correct 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 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 need to be replaced sooner.

Without Furnace Heads Up, you might not detect your furnace is turning on and off frequently, because its blower fan might keep going. 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.

Change Your Air Filter Regularly

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

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

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

Google says if the filter is clean or if your furnace didn’t pass the test, something else could be awry that requires professional assistance. If this happens, contact Wesley Wood Service Experts at 484-401-7577 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 might short cycle. You can tell if there’s a problem by watching your furnace as it turns on. 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.
  • Turn 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 start 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 warm enough, the gas will switch on and the burners will ignite.
  • If the flame sensor can’t detect a flame, it’s usually due to the fact it’s dirty or faulty. Your furnace will then shut off as a safety precaution. If your furnace is short cycling, you'll observe the flame and fan shutting off after a few seconds.

If you’re wondering how flame sensors could get dirty being bathed in fire continuously, a blend of moisture and chemicals in the air form a thin layer of carbon on the surface. Cleaning a dirty flame sensor will stop the short cycling issue. This job is best left to an Expert. That's because an HVAC professional like Wesley Wood Service Experts 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 exhausts combustion gases outside through a PVC pipe. This pipe can get obstructed by snow or bird nests, so you’ll want to make sure it’s always clear. If the pipe gets plugged, it can cause your furnace to overheat. It could also result in carbon monoxide flowing back into your home, creating a potentially deadly situation.

However, modern furnaces have a pressure switch that typically will stop 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 a location that's accessible by tiny hands. Even this little 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 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 Wesley Wood Service Experts can look up the codes for you and determine the problem. Unfortunately, Nest has not developed to the point where it can read the error codes furnace manufacturers produce, so you will still need a pro to help you out.

Let the Experts Handle Your Short Cycling Furnace

If you receive the message, “Nest noticed that your furnace shuts down within 15 minutes of heating,” you know what to do. At Wesley Wood Service Experts, our Experts have the expertise 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 request your appointment, contact us at 484-401-7577 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