Why Does My Furnace Keep Running?
It’s a common concern for homeowners: your furnace keeps running and seems like it’s never stopping. While your furnace is working to keep your home warm, you might be wondering if it’s normal for the system to run continuously, or if it’s a sign of an issue that needs to be addressed.
In this blog, we will dive into the reasons why your furnace might be running non-stop, provide some insights into potential causes, and offer practical solutions. Whether you’re dealing with a dirty air filter, faulty thermostat, or malfunctioning blower fan, we’ve got you covered!
Is It Normal for My Furnace to Keep Running?
Before you panic, it’s important to know that furnaces do need to run for long periods during the coldest months. Your heating system is designed to keep the home warm and maintain a steady temperature. However, if it seems like your furnace is running constantly without reaching the desired temperature, or if it’s running for longer than usual, something could be wrong.
Let’s take a closer look at some of the common causes for a furnace that won’t stop running.
1. Dirty Air Filter
One of the most common reasons for a furnace to run constantly is a dirty air filter. When the air filter is clogged with dust, dirt, and debris, it restricts airflow to the furnace. This causes the furnace to work harder to heat the air, potentially leading to uneven heating or longer run times. A dirty filter can also cause the furnace to overheat, prompting it to keep running in an attempt to reach the set temperature.
Solution: If you suspect a dirty air filter is the issue, turn off your furnace and check the filter. If it appears dirty, replace the furnace air filter with a new one. It’s recommended to change the filter every 1-3 months, depending on the type of filter you use and the level of dust and debris in your home.
2. Incorrect Thermostat Settings
Sometimes the issue isn’t with the furnace itself, but with the thermostat settings. If your thermostat is set incorrectly or is malfunctioning, it may send signals to your furnace to keep running. For example, if the thermostat is set too high, it can cause the furnace to run longer than necessary. Similarly, incorrect fan settings (such as setting the fan to “on” instead of “auto”) will make the blower fan run continuously.
Solution: Double-check the thermostat settings to ensure they are correctly configured. The fan should ideally be set to “auto,” so it only runs when the furnace is actively heating. Also, verify that the temperature settings are correct and that there is no issue with the thermostat calibration.
3. Faulty or Malfunctioning Thermostat
A faulty thermostat can be another culprit behind a furnace that keeps running. If the thermostat is malfunctioning, it might not be able to sense the room temperature properly, causing the furnace to run even when the temperature has already reached the desired level.
Solution: If your thermostat is not functioning as expected, you may need to replace it. A professional HVAC technician can help diagnose whether the thermostat is the problem and advise you on the best course of action.
4. Malfunctioning Blower Fan
Your furnace’s blower fan is responsible for circulating warm air throughout your home. If the blower fan is malfunctioning, it can cause the furnace to run constantly, as the system is not properly circulating air. A malfunctioning blower fan can also lead to cold spots in your home or uneven heating.
Solution: If the blower fan is not working properly, it may need to be repaired or replaced. Contact an HVAC expert to inspect the fan and ensure it’s functioning as it should.
5. Faulty Limit Switch
The limit switch in your furnace is a safety feature that controls the maximum temperature of the system. If the limit switch is faulty, it may not properly shut off the furnace when it reaches the desired temperature. As a result, the furnace could run continuously.
Solution: A faulty limit switch needs to be replaced by a qualified HVAC technician. This is not a DIY repair, as working with electrical components in the furnace can be dangerous.
6. Furnace Control Board Issues
The furnace control board is responsible for managing various operations within the furnace, including the blower fan and ignition system. If the control board malfunctions, it may cause the furnace to run without properly shutting off when the temperature reaches the set level.
Solution: If the control board is malfunctioning, it is best to call a professional HVAC technician to diagnose and repair the furnace issue. A faulty control board is not something that should be dealt with by an untrained person.
7. Blocked or Restricted Airflow
Another reason your furnace might be running constantly is restricted airflow. This could be due to blocked vents, dirty ducts, or an obstruction in the ductwork. When airflow is restricted, your furnace has to work harder to push air through the system, which can lead to longer running times.
Solution: Check your air vents to ensure they are not blocked by furniture or other objects. Additionally, consider scheduling a ductwork cleaning or inspection if you suspect there’s a buildup of dust or debris in the ducts.
8. Older & Non-Efficient Furnaces
If your furnace is older, it may be less energy-efficient and struggle to maintain consistent heating. This can lead to the furnace running longer in an attempt to keep the home warm. Older models are also more prone to mechanical issues, including problems with the blower motor or gas valve.
Solution: If your furnace is more than 15-20 years old, it may be time to consider replacing it with a newer, more energy-efficient model. Upgrading to a modern furnace can help improve furnace efficiency, reduce energy bills, and prevent ongoing issues.
9. Short Cycling
While it may seem like your furnace is always running, it could also be short-cycling, where it turns on and off rapidly. This could be due to a number of issues, such as a dirty air filter, incorrect thermostat settings, or a malfunctioning blower motor.
Solution: If your furnace is short-cycling, it’s important to address the underlying cause. Start by changing the air filter and checking the thermostat settings. If the problem persists, contact an HVAC technician to inspect the system.
FAQs About Furnace Issues
Below, we’ve addressed some of the most commonly asked questions about furnace issues.
It could be due to a dirty air filter, restricted airflow, or a faulty thermostat. Check the filter, vents, and settings. If the issue continues, call Green Street HVAC for furnace repair in Springfield, TN.
Yes, a clogged filter restricts airflow, making the furnace work harder and run longer. Change the filter regularly for better performance.
Check thermostat settings, clean the air filter, and ensure vents are clear. If the issue persists, call an HVAC technician.
If simple fixes don’t work, call a Green Street HVAC technician to check for issues like a faulty limit switch or blower motor. Our HVAC company provides services across the Tri-Cities and surrounding areas in Middle Tennessee.
It could be a faulty thermostat, dirty filter, or airflow blockage. Start by checking the filter and settings, then call Green Street HVAC if needed.
Call Green Street HVAC for Furnace Repair in Tennessee
If your furnace keeps running and you’re not sure why, don’t wait for the problem to get worse. Green Street HVAC is here to help! Our team of experts provides fast, expert service to diagnose and fix furnace issues.
We offer complete HVAC services, including furnace repair, AC repair, HVAC maintenance, and installation. Serving Knoxville, Tri-Cities, and surrounding areas in Middle Tennessee, we make your home stay warm and comfortable. Call Green Street HVAC today at (865) 245-3132 to schedule your furnace repair!
