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

Having a smart thermostat isn’t just wise for spending less on heating expenses. It can also let you know if there’s a problem with your furnace.

The Google Nest has a feature called Furnace Heads Up, which will alert you if it senses an issue with your heating system. You’ll see the warning 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 turns on for a brief period of time then turns off. This HVAC game of red light, green light prevents your home from heating up 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 sooner.

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 simple 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 prematurely to avoid overheating. We recommend changing flat filters once a 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 changed 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 display the wires connected to it. Select “continue.”

• • You’ll see system components displayed. Select “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 done.

Google says if the filter is clean or if your furnace didn’t clear the test, something else could be awry that needs professional help. If this happens, call 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 tell 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 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 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 depends on the furnace model.

• • Once the ignitor is warm enough, the gas will switch on and the burners will light.

• • If the flame sensor can’t sense a flame, it’s usually because it’s dirty or malfunctioning. Your furnace will then shut 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 wondering 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 problem. This task 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 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 obstructed by snow or bird nests, so you’ll want to make sure it’s always clear. If the pipe gets clogged, it can result in your furnace overheating. It could also result in carbon monoxide flowing back into your home, creating a potentially deadly situation.

However, modern furnaces are equipped with a pressure switch that generally will prevent these situations from occurring. Families with young 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 irregular 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 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 check 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 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 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.