Why Does My Furnace Keep Running

Jan 27, 2020

Winter weather can be wildly unpredictable, so now is not the time to find yourself having issues with your furnace. Preventive maintenance is so important when it comes to taking proper care of your HVAC system. Before the cold-weather season descends each year, call us at Canal Winchester Heating & Cooling to schedule a complete inspection and professional cleaning of your HVAC system by one of our trained HVAC specialists. You will feel much better knowing your system is in top shape and is ready for any weather that Mother Nature may throw our way. You can rest assured that your home will be warm and cozy for you and your family throughout the cold-weather season. 


“Short-cycling” refers to your furnace coming on, running for just a few minutes, turning off, and running again repeatedly. When this occurs, your furnace is failing to complete a full operating cycle as it is programmed to do in order to adequately heat your home. There are several reasons this can happen. Some issues you can correct (or prevent) yourself; others will require the assistance of one of our HVAC technicians: 


Reasons Your Furnace Keeps Running 

Your Furnace Needs A New Air Filter 

The air filter traps and holds all of the dirt, dust, and debris that would otherwise end up in the air circulating throughout your home. When it becomes caked and clogged with this gunk, air can’t flow through it anymore. Your furnace will overwork itself trying to keep your home warm. The restricted airflow keeps the heat exchanger from being able to get the amount of air it needs, which results in the heat exchanger becoming too hot. This will cause the system’s fan to run continuously to provide the cold air that is needed to cool down the heat exchanger. This can be easily fixed (and prevented) easily by checking and replacing the filter prior to turning your furnace on for the season. Ensuring that there is always a fresh filter in your furnace is essential to your HVAC system functioning correctly. Jot a reminder to yourself on your calendar to check the air filter once per month during the cold-weather season, and make sure to replace it at least once during the season. 


The Fan Switch is ‘On’ 

The fan switch on your thermostat controls the blower inside the system. It is located on your thermostat. The switch has two settings: ‘Auto’ and ‘On.’ When it is set to the ‘On’ position, the blower will run continuously. This wastes energy and requires your HVAC system to work unnecessarily. The nonstop activity will eventually cause your furnace to become overworked. It can overheat, which can cause severe damage to your HVAC system. Switch the fan setting over to ‘Auto’ so that the fan will operate only when it needs to. 


The Temperature Setting On Your Thermostat Has Increased 

This is such a simple explanation that many people overlook it, but it is actually the most common reason that your furnace has started to run more than usual. If the temperature has been increased, the furnace will naturally run more than usual. When you discover that there is an issue, check your thermostat’s temperature setting. A fix this simple is absolutely preferable to a more serious issue. Set the temperature on your thermostat back to a lower setting. 


The Pilot Flame Is No Longer Burning 

If you notice cold air being blown into your home and short-cycling occurring, this is a good indication that the pilot light has been extinguished inside your furnace. If this happens, the furnace will run continuously because it is still trying to heat your home as it is programmed to do. You can re-light the pilot light on your own if you know how or have a 

professional do it for you. Call us, and we will send one of our HVAC technicians to light your furnace’s pilot flame and get your system working properly once more. 


The Fan Limit Switch Is Defective 

In the event your furnace’s fan limit switch gets damaged or just becomes worn out, your furnace may start to short cycle. The fan limit switch is found under the furnace’s hood. It controls the blower. This switch has a probe-like device that activates the fan automatically if the burner assembly becomes overheated. Once it has cooled down, the probe shuts the fan off again. If either of these components becomes damaged or gets stuck in the ‘On’ position, then the blower will run nonstop. 


Still Need Help With Your Furnace?

If you think this could be the problem, give us a call and one of our HVAC specialists will take a look, find the problem, and repair it. If your furnace is running in short cycles, not heating your home sufficiently, or otherwise giving you cause for concern, call Canal Winchester Heating & Cooling at 614-524-4737 or visit our webpage at https://cwheating.com/schedule-now/. One of our fully trained and licensed HVAC technicians will inspect your system, locate the issue, and repair it right away. We are here for you 24 hours a day, seven days a week, 365 days a year for your convenience, to assist you with all your HVAC needs. 




7300 Emerald Tree Dr
Canal Winchester, OH 43110