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Dec 28, 2023 12:35:26 PM by Logan Donahue

6 Reasons Your Furnace Keeps Shutting Off

Are you frustrated with your furnace continually shutting down and leaving you feeling cold in the chilly air? Dealing with this issue can be quite frustrating and inconvenient. In this blog post, we will delve into the root causes of this problem and provide you with practical solutions to address it effectively.

1. Your Filter is Clogged

Dirty furnace filter

When the air filter becomes congested with dust, dirt, and debris, it restricts airflow and causes your furnace to shut off as a safety measure. This is why it's important to regularly clean or replace the air filter to ensure proper functioning.

2. Your Flame Sensor is Malfunctioning 

Additionally, a malfunctioning flame sensor could be the culprit. The flame sensor's role is to detect the presence of a flame and signal the furnace to continue running. If the sensor is dirty or damaged, it may not recognize the flame, resulting in frequent shutdowns. Cleaning or replacing the flame sensor can often resolve this issue.

3. Your Thermostat is Malfunctioning

Person turning down the heat on their thermostat to 72 degrees.

Another possibility is a malfunctioning thermostat. A faulty thermostat can send incorrect signals to your furnace, causing it to shut off prematurely. Check if your thermostat is set to the desired temperature and consider replacing it if needed.

4. There is an Insufficient Gas Supply

Insufficient gas supply can also lead to a furnace that won't stay on. If the gas valve is partially closed or obstructed, it can disrupt the fuel supply, resulting in frequent shutdowns. Check the gas valve to ensure it is fully open and free of any blockages.

5. Your Furnace is Overheating

Overheating furnace flames

Furthermore, a furnace that is overheating may shut off as a safety precaution. This can occur due to a malfunctioning limit switch, blocked vents, or a dirty blower motor. Regular maintenance, such as cleaning the vents and ensuring proper airflow, can help prevent overheating and ensure your furnace stays on.

6. Your Furnace is Aging Out 

Lastly, it's important to consider the age and condition of your furnace. If your furnace is old or has been neglected, it may have worn-out components that need replacement. In such cases, it's advisable to consult a professional HVAC technician who can assess the situation and provide the necessary repairs or recommend a new furnace.


In conclusion, a furnace that won't stay on can be caused by various factors, ranging from dirty filters to faulty components. By understanding these potential issues and taking appropriate action, you can restore the functionality of your furnace and enjoy a warm and comfortable home. Remember, if you're uncertain or uncomfortable performing any maintenance or repairs yourself, always seek assistance from an HVAC professional. Stay warm!
Contact ECI Comfort

If you live in the Delaware Valley/Greater Philadelphia area and would like to find comfort within your home, visit our website or give us a call at 215 - 245 - 3200 to learn more.

This entry was posted in Save Energy, Heating, Heater Safety, Furnace, Gas Furnace

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