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

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

The Google Nest is equipped with a feature called Furnace Heads Up, which will alert you if it notices a problem 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 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 switches on for a brief period of time then switches off. This HVAC game of red light, green light stops your home from being warm and can drive up your energy bill. It can also increase wear and tear on your furnace. It may also be more likely to break down and may even require replacement more quickly. 

Without Furnace Heads Up, you might not detect your furnace is turning on and off often, because its blower fan might keep going. This feature can recognize power interruptions that occur 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 restrict airflow. Your furnace will then shut down prematurely to avoid overheating. We recommend changing flat filters once a month, and pleated filters every three months. It’s easy to stay on top of replacing your filter by setting up a Filter Reminder on your thermostat. 

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

  • Press 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 displayed. Hit “test.” 
  • Choose “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 done. 

Google says if the filter is clean or if your furnace didn’t clear the test, something else could be awry that needs professional help. If this happens, contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 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 paying attention to your furnace as it turns on. Here’s what to look for. 

  • Remove the door from your furnace so you can see 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 turn on the heat, the fan will begin running 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 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 down after a couple of seconds. 

If you’re wondering how flame sensors could get dirty being bathed in fire constantly, a combination 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 Service Experts Heating, Air Conditioning & Plumbing 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 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 clogged, it can result in your furnace overheating. It could also result in carbon monoxide flowing back into your home, creating a potentially fatal situation. 

However, modern furnaces are equipped with a pressure switch that generally will stop these situations from occurring. Families with young children will often find their kids have jammed 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 trips the pressure switch, which shuts off the burners. If this is the root of your problem, you will encounter short cycling and a furnace error code specifying the pressure switch was triggered. 

An Expert HVAC technician from Service Experts Heating, Air Conditioning & Plumbing can check 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 create, 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 Service Experts Heating, Air Conditioning & Plumbing, our Experts have the knowledge to resolve any furnace problem quickly and affordably. What’s even better is that we back our repairs with a 100% Satisfaction Guarantee for one year.* To book your appointment, contact us at 866-397-3787 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.