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

Using a smart thermostat isn’t just wise for saving on heating costs. It can also alert you if there’s a problem with your furnace.

The Google Nest is equipped with a feature called Furnace Heads Up, which will let you know 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 common issues is: “Nest noticed that your furnace shuts down within 15 minutes of heating.” Here’s why this is happening 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 switches on for a brief period of time then switches 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 wear and tear 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 detect your furnace is turning on and off often, since its blower fan might keep going. This feature can pick up on 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.

Replace Your Air Filter Regularly

If your air filter is too dirty, it will restrict airflow. Your furnace will then shut off early to avoid overheating. We recommend replacing flat filters every month, and pleated filters every three months. It’s simple to stay on top of replacing 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 repairs the problem.

Push the ring to bring up the Quick View menu, where you’ll select "settings" and then "equipment."
The thermostat will show the wires linked to it. Select "continue."
You’ll see system components shown. 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 pass the test, something else could be wrong that needs professional help. If this happens, contact Stallion Heating Plumbing Air Conditioning at 215-278-9690 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 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 varies according to the furnace model.
Once the ignitor is hot enough, the gas will turn on and the burners will ignite.
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 notice the flame and fan shutting down after a few seconds.

If you’re questioning how flame sensors could get dirty being bathed in fire continuously, a combination of moisture and chemicals in the air form a thin layer of carbon on the surface. Cleaning a dirty flame sensor will stop the short cycling problem. This job is best left to an Expert. That's due to the fact an HVAC professional like Stallion Heating Plumbing Air Conditioning 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 exhausts combustion gases outside 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 clogged, it can result in your furnace overheating. 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. 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 trip the pressure switch. The uneven flow of air into and out of the system triggers the pressure switch, which shuts down the burners. If this is the root of your problem, you will experience short cycling and a furnace error code specifying the pressure switch was triggered.

An Expert HVAC technician from Stallion Heating Plumbing Air Conditioning can check 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 create, so you will still need a pro to help you out.

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 Stallion Heating Plumbing Air Conditioning, 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 215-278-9690 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.