A gas furnace that runs constantly can be a frustrating and concerning issue for homeowners. This problem can lead to higher energy bills, wear and tear on the furnace, and potential safety hazards. In this comprehensive blog post, we’ll explore the common causes of a gas furnace that keeps running, provide troubleshooting steps, and offer guidance on how to fix the problem.
Why Does My Gas Furnace Keep Running Constantly?
There are several potential reasons why a gas furnace may run continuously, including:
1. Dirty or Clogged Air Filter
A dirty or clogged air filter restricts airflow, forcing the furnace to work harder and run longer to achieve the desired temperature. This is one of the most common causes and can be easily resolved by replacing the filter every 1-3 months.
2. Malfunctioning Thermostat
If the thermostat is not calibrated correctly or is malfunctioning, it may not signal the furnace to turn off properly. This can cause the furnace to run continuously. Check the thermostat settings and ensure it is set to “Auto” instead of “On” for the fan.
3. Ductwork Issues
Leaks or blockages in the ductwork can cause the furnace to work harder, leading to continuous operation. Inspect and clean the ducts regularly to prevent this.
4. Dirty Gas Burners
Dirty or clogged gas burners can lead to incomplete combustion, reducing heat production and causing the furnace to run longer. Inspect the burner flames; they should be strong and blue.
5. Incorrect Thermostat Settings
If the thermostat is set too high, the furnace may run constantly to try to meet the demand. Lowering the temperature can help.
6. Furnace Size
An undersized furnace will have to work harder to heat the home, leading to continuous operation. Ensure the furnace is properly sized for your home.
7. Electrical Issues
Problems with the control board, relays, or wiring can cause the furnace fan to run continuously. This may require professional diagnosis and repair.
How Can I Troubleshoot and Fix a Gas Furnace That Won’t Turn Off?
To troubleshoot and fix a gas furnace that keeps running, follow these steps:
- Check the Air Filter: Inspect the air filter for dirt and debris. Replace it if necessary.
- Adjust Thermostat Settings: Ensure the thermostat is set to “Auto” for the fan and not “On”. Lower the temperature setting to see if the furnace cycles off.
- Inspect Ductwork: Check for leaks or blockages in the ducts. Seal any leaks and clean the ducts to improve airflow.
- Check Gas Burners: Inspect the burner flames. They should be strong and blue. Clean the burners if necessary.
- Check Thermostat Calibration: Ensure the thermostat is calibrated correctly. Replace the batteries if it is battery-operated.
- Inspect Electrical Components: If the issue persists, it may be due to electrical problems such as a bad control board or relay. This requires professional diagnosis and repair.
What Tools and Products Are Needed?
To troubleshoot and fix a gas furnace that keeps running, you may need the following tools and products:
- New Air Filter: Depending on the type and size, costs vary but are generally inexpensive (around $10-$30).
- Thermostat Batteries: If your thermostat is battery-operated, replace the batteries (cost around $5-$10).
- Duct Sealant: For sealing leaks in ductwork (cost around $10-$20).
- Professional HVAC Tools: For diagnosing electrical issues, which may require a professional HVAC technician.
Estimated Costs for Repairs
The estimated costs for repairing a gas furnace that keeps running can vary depending on the underlying issue:
- Replacing Air Filter: $10-$30
- Replacing Thermostat Batteries: $5-$10
- Sealing Duct Leaks: $10-$20
- Professional Diagnosis and Repair: Varies widely depending on the issue, but can range from $100 to $500 or more.
Remember, it’s always best to consult with a professional HVAC technician if you’re unsure about the cause of the problem or if the issue persists after trying the troubleshooting steps.
Reference:
- Nugent & Sons: Furnace Running Constantly? | Our HVAC Experts Can Help
- Apollo Services: 9 Possible Reasons Why Your Furnace Is Constantly Running
- Smile HVAC: 5 Reasons Why Your Furnace is Running Constantly
- TLC Plumbing: Why is my furnace running constantly?
- Reddit – HVAC Advice: furnace fan running continuously
