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

Using 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 has a feature called Furnace Heads Up, which will alert you 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 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 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 brief 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 wear and tear 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, 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.

Change Your Air Filter Often

If your air filter is too dirty, it will restrict airflow. Your furnace will then shut off prematurely to avoid overheating. We recommend replacing flat filters every month, and pleated filters every three months. It’s easy 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 bring up the Quick View menu, where you’ll select “settings” and then “equipment.”

• • The thermostat will display the wires connected to it. Select “continue.”

• • You’ll see system components displayed. Select “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 clear the test, something else could be awry that requires professional assistance. 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 bad flame sensor is another top reason why your furnace might short cycle. You can tell 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.

• • Turn on the furnace by setting the thermostat to a higher indoor temperature.

• • When you switch 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 depends on 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 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 down after a few seconds.

If you’re wondering how flame sensors could get dirty being bathed in fire continuously, 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 problem. 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 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 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 result in your furnace overheating. 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 stop these situations from occurring. Households with young children will often find their kids have stuffed toy cars, sticks or nuts into the exhaust if it’s in an area that can be reached by little hands. Even this little amount is enough to trip 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 encounter short cycling and a furnace error code indicating 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 read the error codes furnace manufacturers create, 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, 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.