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

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

The Google Nest has a feature called Furnace Heads Up, which will let you know if it senses an issue with your heating system. You’ll notice the warning on the thermostat, in the app and in your monthly Nest Home report.

One of the most typical issues 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 turns on for a brief period of time then turns 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 susceptible to breaking down and may even require replacement more quickly.

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 detect power interruptions that occur 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.

Replace 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 once a 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 changed your filter after getting a Furnace Heads Up alert, you can do a test to see if that repairs the problem.

Press the ring to bring up the Quick View menu, where you’ll choose "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 run a 15-minute heating test and tell you the results when it’s done.

Google says if the filter is clean or if your furnace didn’t pass the test, something else could be wrong that requires professional help. If this happens, call Chief/Bauer Service Experts at 217-689-2469 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 is short cycling. You can tell if there’s a problem by watching your furnace as it turns on. Here’s what to check for.

Remove 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 warmer indoor temperature.
When you turn on the heat, the fan will turn on first. You should notice 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 malfunctioning. Your furnace will then turn off as a safety measure. If your furnace is short cycling, you'll observe the flame and fan shutting off after a few seconds.

If you’re questioning how flame sensors could get dirty being bathed in fire continuously, a blend 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 task is best left to an Expert. That's due to the fact an HVAC professional like Chief/Bauer Service Experts 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 outside through a PVC pipe. This pipe can get clogged 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 cause carbon monoxide to flow back into your home, creating a potentially life-threatening situation.

However, modern furnaces have a pressure switch that typically will stop these situations from occurring. Families with small children will often find their kids have stuffed toy cars, sticks or nuts into the exhaust if it’s in a location that can be reached by little hands. Even this small amount is enough to trigger 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 underlying cause of your problem, you will encounter short cycling and a furnace error code indicating the pressure switch was tripped.

An Expert HVAC technician from Chief/Bauer Service Experts can look up the codes for you and diagnose the problem. Unfortunately, Nest has not evolved to the point where it can read the error codes furnace manufacturers produce, so you will still need a pro to help you out.

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 Chief/Bauer Service Experts, our Experts have the knowledge to resolve 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 book your appointment, contact us at 217-689-2469 or schedule online.

*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.