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

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

The Google Nest is equipped with a feature called Furnace Heads Up, which will let you know if it detects 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 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 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 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 deterioration on your furnace. It may also be more likely to break down and may even require replacement sooner.

Without Furnace Heads Up, you might not notice 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 easy ways you can keep your furnace from short cycling.

Replace 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 encourage changing flat filters once a month, and pleated filters every three months. It’s simple to stay on top of changing your filter by setting up a Filter Reminder on your thermostat.

If you’ve changed your filter after getting a Furnace Heads Up alert, you can do a test to see if that repairs 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 linked to it. Select "continue."
  • You’ll see system components shown. Select "test."
  • Choose "Furnace Heads Up" and follow the instructions. Your furnace will go through a 15-minute heating test and give you the results when it’s done.

Google says if the filter is clean or if your furnace didn’t pass the test, something else could be wrong that needs professional help. If this happens, call Eveready Service Experts at 804-548-4480 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 determine 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 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 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 warm enough, the gas will switch on and the burners will ignite.
  • If the flame sensor can’t sense a flame, it’s usually because it’s dirty or defective. 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 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 end the short cycling problem. This task is best left to an Expert. That's due to the fact an HVAC professional like Eveready 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 Often

Your high-efficiency furnace exhausts combustion gases outside 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 fatal situation.

However, modern furnaces are equipped with a pressure switch that typically will prevent these situations from occurring. 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 irregular flow of air into and out of the system triggers the pressure switch, which shuts off 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 tripped.

An Expert HVAC technician from Eveready Service Experts can look up the codes for you and diagnose the problem. Unfortunately, Nest has not evolved to the point where it can interpret 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 get the message, “Nest noticed that your furnace shuts down within 15 minutes of heating,” you know what to do. At Eveready Service Experts , our Experts have the expertise 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 804-548-4480 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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