If you have a furnace fan that keeps running, you are not alone. This issue happens to homeowners across the country and even some right in the Edwardsville, IL area. We have several solutions for you on how to diagnose the problem and come to a solution to ensure that your furnace fan is not running for no reason.

furnace fan

First, try seeing if your thermostat fan is set on AUTO and not ON. After doing this turn the temperature on the thermostat lower than the current room temperature and wait approximately 3 to 4 minutes. If the furnace fan is still running, then we know that there is a problem. If your furnace fan won’t turn off you are most likely dealing with one of these three problems:

Unfortunately, you will need a professional to fix those last two problems. But before you make the call to a local professional, check to see if your fan limit switch is set correctly. Keep reading to find out how to do this simple correction.

Step 1: Locate Your Furnace Fan Limit Switch

Your fan limit switch is located inside of the furnace panel cover, usually located in the upper right corner. The fan limit switch is responsible for turning the blower on and off and the proper times. When the switch is working correctly, the fan should turn on several minutes after the thermostat calls for heat and turn off several minutes after the heat cycle ends. But if your furnace fan continues to run, regardless of whether the furnace is heating or not, your furnace fan limit switch is either; set to Manual Incorrectly or is Faulty and needs to be repaired or replaced. Now that you have located your fan limit switch, let’s look to see how you can determine whether it is properly set or not.

Step 2: Make Sure the White Button is NOT Pressed In

Your fan limit switch will have a small white button on the lower-left corner of it. That button tells the switch whether to operate in manual or automatic. In manual mode, the fan will be on all the time, whereas in automatic mode the fan only runs during heating cycles. If the button is pressed in, the switch is then set to manual mode and is forcing the fan to continuously run. You will need to reset it to automatic mode to allow for proper fan operation.

furnace fan

Step 3: Call a Professional If the Fan is Still Running

If your fan limit switch is set to automatic but the fan is continuing to run without ever stopping, you will need to call an HVAC professional. If you are in need of a professional give our team at B & W Heating & Cooling a call today!