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 alert you if there’s a problem with your furnace.

The Google Nest is equipped with a function called Furnace Heads Up, which will let you know if it notices an issue with your heating system. You’ll see the alert on the thermostat, in the app and in your monthly Nest Home report.

One of the most common problems 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 switches on for a brief period of time then switches off. This HVAC game of red light, green light prevents 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 need to be replaced more quickly.

Without Furnace Heads Up, you might not detect your furnace is turning on and off frequently, since its blower fan might keep going. 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 prevent your furnace from short cycling.

Replace Your Air Filter Regularly

If your air filter is too dirty, it will limit airflow. Your furnace will then shut off prematurely to avoid overheating. We recommend changing flat filters every 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 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 pull up the Quick View menu, where you’ll select “settings” and then “equipment.”

• • The thermostat will show the wires connected to it. Choose “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 tell 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 awry that requires 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 is short cycling. You can determine if there’s a problem by watching your furnace as it turns on. Here’s what to look for.

• • Remove 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 turn on the heat, the fan will begin running first. You should notice 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 light.

• • If the flame sensor can’t sense a flame, it’s usually due to the fact it’s dirty or malfunctioning. Your furnace will then turn off as a safety measure. If your furnace is short cycling, you’ll notice the flame and fan shutting down after a few 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 issue. This job is best left to an Expert. That’s because 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 outdoors through a PVC pipe. This pipe can get blocked 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 have a pressure switch that generally will prevent these situations from occurring. 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’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 trips the pressure switch, which shuts down 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 look up the codes for you and determine 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 assist you.

Let the Experts Solve 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 expertise 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 book your appointment, contact us at 866-397-3787 or schedule online.

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*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.