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

Using a smart thermostat isn’t just smart for spending less 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 alert you if it notices 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 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,” that means your furnace is short cycling. Short cycling is when the furnace turns 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 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 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 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 prevent your furnace from short cycling. 

Replace Your Air Filter Regularly 

If your air filter is too dirty, it will limit airflow. Your furnace will then shut down prematurely to prevent overheating. We recommend changing 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 fixes the problem. 

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

• The thermostat will show the wires linked 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 test and tell 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 wrong that requires professional assistance. If this happens, call Service Experts Heating & Air Conditioning at 954-736-4314 for furnace repair. 

Clean or Replace Your Furnace’s Flame Sensor 

Having a dirty or bad flame sensor is another top explanation why your furnace might short cycle. You can determine 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 higher 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 warm enough, the gas will turn on and the burners will light. 
• If the flame sensor can’t sense a flame, it’s usually because it’s dirty or defective. Your furnace will then turn off as a safety precaution. If your furnace is short cycling, you’ll notice the flame and fan shutting off after a couple of 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 issue. This job is best left to an Expert. That’s because an HVAC professional like Service Experts Heating & Air Conditioning 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 obstructed by snow or bird nests, so you’ll want to make sure 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 deadly situation. 

However, modern furnaces have 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 a location that can be reached by tiny hands. Even this little amount is enough to trip 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 root of your problem, you will encounter short cycling and a furnace error code specifying the pressure switch was tripped. 

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

Let the Experts Solve 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, 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, contact us at 954-736-4314 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.