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 a problem with your furnace. 

The Google Nest has a feature called Furnace Heads Up, which will let you know if it notices a problem 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 fix 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 heating up 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 notice 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 easy ways you can keep your furnace from short cycling. 

Change 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 changing flat filters every month, and pleated filters every three months. It’s easy to stay on top of replacing 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 run a test to see if that repairs the problem. 

• Push the ring to pull 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. Select “test.” 
• Select “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 done. 

Google says if the filter is clean or if your furnace didn’t pass the test, something else could be awry that requires professional help. If this happens, contact Service Experts Heating & Air Conditioning at 403-279-5760 for furnace repair. 

Clean or Replace Your Furnace’s Flame Sensor 

Having a dirty or malfunctioning flame sensor is another top explanation why your furnace is short cycling. You can determine if there’s a problem by watching your furnace as it starts up. Here’s what to check for. 

• Remove the door from your furnace so you can look at the burners. If you have a viewport in the furnace door, you may not need to remove the door for this. 
• Switch 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 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 turn on and the burners will light. 
• 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 shut off as a safety precaution. 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 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 breaking it or be able to tell you if you need a new one. 

Check Your Furnace’s Exhaust Pipe Frequently 

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 plugged, it can cause your furnace to overheat. 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 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 little amount is enough to trigger the pressure switch. The uneven 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 specifying 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 developed 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 Service Experts Heating & Air Conditioning, our Experts have the knowledge to resolve 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 book your appointment, call us at 403-279-5760 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.