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

Having a smart thermostat isn’t just wise for saving on heating expenses. It can also let you know if there’s an issue 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 alert on the thermostat, in the app and in your monthly Nest Home report. 

One of the most typical 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 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 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 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 detect your furnace is turning on and off often, since its blower fan might keep running. This feature can recognize power interruptions that happen 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. 

Change Your Air Filter Regularly 

If your air filter is too dirty, it will limit airflow. Your furnace will then shut off prematurely to avoid overheating. We encourage replacing flat filters every month, and pleated filters every three months. It’s simple to stay on top of changing your filter by adding a Filter Reminder on your thermostat. 

If you’ve replaced your filter after getting a Furnace Heads Up alert, you can do a test to see if that fixes 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 linked to it. Choose “continue.” 
• You’ll see system components displayed. Hit “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 clear the test, something else could be wrong that needs 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 reason why your furnace is short cycling. You can tell if there’s a problem by watching 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 have to remove the door for this. 
• Switch on the furnace by setting the thermostat to a higher 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 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 precaution. If your furnace is short cycling, you’ll notice the flame and fan shutting off after a few seconds. 

If you’re wondering how flame sensors could get dirty being bathed in fire continuously, a combination 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 issue. This task 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 breaking 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 outside through a PVC pipe. This pipe can get clogged 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 cause carbon monoxide to flow back into your home, creating a potentially fatal situation. 

However, modern furnaces have a pressure switch that generally will prevent these situations from happening. 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 can be reached by tiny hands. Even this small amount is enough to trigger the pressure switch. The uneven 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 experience short cycling and a furnace error code indicating the pressure switch was tripped. 

An Expert HVAC technician from Service Experts Heating & 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 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 stand behind our repairs with a 100% Satisfaction Guarantee for one year.* To request your appointment, call 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.