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

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

The Google Nest has a function called Furnace Heads Up, which will let you know if it senses 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 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 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 short period of time then switches off. This HVAC game of red light, green light stops your home from being warm and can increase 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 more quickly.

Without Furnace Heads Up, you might not detect your furnace is turning on and off frequently, because its blower fan might keep running. This feature can pick up on 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 early to avoid overheating. We encourage changing flat filters every 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 replaced your filter after receiving 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 select "settings" and then "equipment."
  • The thermostat will display the wires linked to it. Select "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 test and give 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 needs professional assistance. If this happens, call Parker Pearce Service Experts at 301-476-4577 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 determine if there’s a problem by paying attention to your furnace as it starts up. 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 have 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 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 turn on and the burners will ignite.
  • If the flame sensor can’t detect a flame, it’s usually because it’s dirty or malfunctioning. Your furnace will then turn off as a safety measure. If your furnace is short cycling, you'll observe the flame and fan shutting off after a couple of seconds.

If you’re questioning how flame sensors could get dirty being bathed in fire constantly, a blend 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 issue. This task is best left to an Expert. That's due to the fact an HVAC professional like Parker Pearce 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 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 ensure that it’s always clear. If the pipe gets blocked, it can cause your furnace to overheat. It could also result in carbon monoxide flowing back into your home, creating a potentially life-threatening situation.

However, modern furnaces are equipped with a pressure switch that typically will prevent these situations from happening. Families with small 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 tiny hands. Even this little amount is enough to trip 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 tripped.

An Expert HVAC technician from Parker Pearce Service Experts can look up the codes for you and diagnose 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 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 Parker Pearce 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, contact us at 301-476-4577 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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