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

Using a smart thermostat isn’t just smart for saving on heating expenses. 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 alert you 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 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,” 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 need to be replaced sooner.

Without Furnace Heads Up, you might not notice your furnace is turning on and off frequently, since its blower fan might keep running. This feature can recognize power interruptions that take place during short cycling.

How Do I Keep My Furnace from Short Cycling?

There are a few simple ways you can prevent your furnace from short cycling.

Change Your Air Filter Often

If your air filter is too dirty, it will limit airflow. Your furnace will then shut off early to avoid overheating. We recommend 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 getting a Furnace Heads Up alert, you can do a test to see if that fixes the problem.

• • Press 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 displayed. Hit “test.”

• • Select “Furnace Heads Up” and follow the instructions. Your furnace will run 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 pass 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 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 need 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 begin running first. You should hear it turn on.

• • The ignitor will start 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 ignite.

• • If the flame sensor can’t detect a flame, it’s usually due to the fact 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 off 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 end the short cycling problem. This job 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 you need a new one.

Check Your Furnace’s Exhaust Pipe Frequently

Your high-efficiency furnace exhausts 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 plugged, it can result in your furnace overheating. It could also cause carbon monoxide to flow back into your home, creating a potentially deadly situation.

However, modern furnaces are equipped with a pressure switch that generally will stop these situations from happening. Families with small children will often find their kids have stuffed toy cars, sticks or nuts into the exhaust if it’s in an area 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 off 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 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 interpret the error codes furnace manufacturers produce, so you will still require 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 expertise to fix 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 request your appointment, call 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.