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

Using a smart thermostat isn’t just wise 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 let you know if it senses 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 why this is happening 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,” it’s saying your furnace is short cycling. Short cycling is when the furnace switches on for a short period of time then turns off. This HVAC game of red light, green light prevents 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 susceptible to breaking down and may even need to be replaced more quickly.

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 take place during short cycling.

How Do I Keep My Furnace from Short Cycling?

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

Change Your Air Filter Regularly

If your air filter is too dirty, it will restrict airflow. Your furnace will then shut down early to prevent overheating. We recommend replacing flat filters every month, and pleated filters every three months. It’s easy to stay on top of replacing your filter by setting up a Filter Reminder on your thermostat.

If you’ve replaced your filter after getting a Furnace Heads Up alert, you can run a test to see if that repairs the problem.

• • Push the ring to bring up the Quick View menu, where you’ll choose “settings” and then “equipment.”

• • The thermostat will show the wires connected to it. Choose “continue.”

• • You’ll see system components shown. Hit “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 done.

Google says if the filter is clean or if your furnace didn’t clear the test, something else could be wrong 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 reason 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 check 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 higher 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 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 defective. Your furnace will then turn 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 issue. 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 damaging it or be able to tell you if you need a new one.

Check Your Furnace’s Exhaust Pipe Often

Your high-efficiency furnace vents combustion gases outdoors through a PVC pipe. This pipe can get obstructed by snow or bird nests, so you’ll want to make sure it’s always clear. If the pipe gets plugged, it can cause your furnace to overheat. It could also result in carbon monoxide flowing back into your home, creating a potentially fatal situation.

However, modern furnaces are equipped with a pressure switch that generally 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’s accessible 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 down the burners. If this is the underlying cause of your problem, you will experience short cycling and a furnace error code indicating the pressure switch was tripped.

An Expert HVAC technician from Service Experts Heating, Air Conditioning & Plumbing can check 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 create, so you will still require a pro to assist you.

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 Service Experts Heating, Air Conditioning & Plumbing, our Experts have the expertise to resolve 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, 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.