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

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

The Google Nest is equipped with a function called Furnace Heads Up, which will alert you if it detects 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 frequent 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 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 switches on for a short period of time then turns 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 likely to break down and may even require replacement more quickly. 

Without Furnace Heads Up, you might not detect your furnace is turning on and off often, 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 easy ways you can prevent your furnace from short cycling. 

Replace Your Air Filter Often 

If your air filter is too dirty, it will limit airflow. Your furnace will then shut off early to prevent overheating. We encourage 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 getting a Furnace Heads Up alert, you can run a test to see if that repairs the problem. 

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

• The thermostat will show the wires connected to it. Choose “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 check 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 awry that needs professional assistance. If this happens, contact Service Experts Heating, Air Conditioning & Plumbing at 866-397-3787 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 is short cycling. You can tell if there’s a problem by paying attention to 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 have to remove the door for this. 
• Switch on the furnace by setting the thermostat to a warmer indoor temperature. 
• When you switch 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 hot enough, the gas will switch on and the burners will ignite. 
• If the flame sensor can’t sense a flame, it’s usually due to the fact it’s dirty or faulty. Your furnace will then shut off as a safety precaution. If your furnace is short cycling, you’ll observe 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 blend of moisture and chemicals in the air form a thin layer of carbon on the surface. Cleaning a dirty flame sensor will end the short cycling issue. This job is best left to an Expert. That’s because an HVAC professional like Service Experts Heating, Air Conditioning & Plumbing 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 ensure that it’s always clear. If the pipe gets clogged, it can cause your furnace to overheat. 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 generally will prevent these situations from happening. Families with small 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 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 root of your problem, you will experience short cycling and a furnace error code specifying the pressure switch was tripped. 

An Expert HVAC technician from Service Experts Heating, Air Conditioning & Plumbing can look up the codes for you and diagnose the problem. Unfortunately, Nest has not developed to the point where it can interpret the error codes furnace manufacturers create, so you will still need a pro to assist you. 

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 Service Experts Heating, Air Conditioning & Plumbing, our Experts have the expertise 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 request your appointment, call us at 866-397-3787 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.