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

Using a smart thermostat isn’t just wise 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 feature called Furnace Heads Up, which will alert you if it detects 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 typical 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,” that means your furnace is short cycling. Short cycling is when the furnace switches on for a short period of time then turns 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 likely to break 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 recognize power interruptions that happen during short cycling.

How Do I Keep My Furnace from Short Cycling?

There are a few simple ways you can keep 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 off early to prevent overheating. We recommend changing flat filters once a month, and pleated filters every three months. It’s simple to stay on top of replacing 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 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. Select "continue."
  • You’ll see system components shown. 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 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 Stevenson Service Experts at 937-503-7896 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 is short cycling. You can determine if there’s a problem by paying attention to 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 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 switch on and the burners will light.
  • If the flame sensor can’t detect a flame, it’s usually because it’s dirty or malfunctioning. Your furnace will then shut off as a safety measure. If your furnace is short cycling, you'll notice the flame and fan shutting down after a couple of seconds.

If you’re questioning how flame sensors could get dirty being bathed in fire constantly, a combination 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 problem. This job is best left to an Expert. That's because an HVAC professional like Stevenson Service Experts will be able to clean it without damaging it or be able to tell you if it needs to be replaced.

Check Your Furnace’s Exhaust Pipe Frequently

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 blocked, it can result in your furnace overheating. It could also cause carbon monoxide to flow back into your home, creating a potentially fatal situation.

However, modern furnaces are equipped with a pressure switch that generally will prevent 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 little hands. Even this small amount is enough to trigger 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 experience short cycling and a furnace error code specifying the pressure switch was triggered.

An Expert HVAC technician from Stevenson Service Experts can check the codes for you and determine the problem. Unfortunately, Nest has not developed to the point where it can interpret the error codes furnace manufacturers produce, so you will still need a pro to assist you.

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 Stevenson Service Experts, our Experts have the knowledge to fix 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 request your appointment, call us at 937-503-7896 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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