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Furnace Failures To Avoid For A Fuss-Free Thanksgiving


As the Thanksgiving feast approaches and the crisp autumn air settles in, the warmth of our Bend, Oregon homes becomes paramount to the season’s celebration. However, imagine the scenario: friends and family gathered, the aroma of a Thanksgiving feast wafting through the air, but suddenly, the furnace falters, leaving everyone in a chilly predicament. In this blog post, we discuss the 12 common failures of a furnace and quick tips for furnace maintenance. Let’s ensure that your furnace is up to the task of warming you and your family this Thanksgiving. 

1. Ignition Issues

Pilot Light Malfunction

  • Dirty or clogged pilot orifice: Over time, dust and debris can accumulate, obstructing the pilot opening. Regular cleaning can resolve this issue.
  • Thermocouple problems: A faulty thermocouple can cause the pilot light to go out frequently. Replacing the thermocouple is a common solution.
  • Gas supply issues: Low gas pressure or a disrupted gas supply can lead to pilot light failure. Verify the gas line and pressure to ensure proper functioning.

Igniter Problems

  • Worn-out igniter: Igniters can deteriorate over time, resulting in ignition failure. Replacement of the igniter is often necessary.
  • Ignition control module issues: A malfunctioning control module can lead to inconsistent ignition. Inspecting and replacing the control module may resolve this issue.

2. Airflow Problems

Clogged Air Filters

  • Neglecting filter replacement: Dirty filters restrict airflow, causing the furnace to overheat and potentially tripping the limit switch. Regularly changing filters is crucial for maintaining proper airflow.
  • Use of incorrect filter type: Using filters with the wrong MERV rating or size can impede airflow. Ensure the filters are the right size and efficiency for your furnace.

Blocked Vents and Ducts

  • Obstructed air vents: Blocked vents limit the flow of air, causing strain on the furnace and reducing efficiency. Regularly check and clear vents to maintain optimal airflow.
  • Blocked ductwork: Accumulated dust, debris, or even pests can obstruct ducts, hindering proper airflow. Periodic duct cleaning can prevent this issue.

3. Thermostat Malfunctions

Incorrect Settings

  • Incorrect temperature settings: Misconfigured thermostat settings can lead to temperature discrepancies. Verify and adjust the thermostat settings to match your comfort preferences.

Faulty Wiring

  • Loose or damaged wiring: Faulty wiring can disrupt communication between the thermostat and the furnace. Inspect and repair any loose or damaged wires to ensure proper functionality.

4. Mechanical Failures

Blower Motor Issues

  • Overheating motor: Over time, the blower motor can overheat, leading to furnace failure. Regular lubrication and proper maintenance can extend the motor’s lifespan.
  • Belt problems: A worn-out or loose belt can cause the blower to malfunction. Replacing or tightening the belt is a common solution.

Limit Switch Failures

  • Tripped limit switch: Overheating due to restricted airflow can cause the limit switch to trip, shutting down the furnace. Addressing airflow issues and replacing a malfunctioning limit switch can resolve this problem.

5. Gas Valve Problems

Valve Blockages

  • Dirt or debris in the gas valve: Contaminants in the gas valve can obstruct gas flow, leading to ignition issues. Regular maintenance, including cleaning the valve, is crucial. It’s important to trust a reliable furnace repair to fix this issue.

Valve Malfunctions

  • Faulty gas valve: A malfunctioning gas valve may fail to open or close properly, affecting the furnace’s ability to heat. Replacement of the gas valve is often necessary to restore normal operation.

6. System Control Board Failures

Electrical Issues

  • Power surges: Electrical surges can damage the system control board, leading to erratic furnace behavior. Installing surge protectors can help prevent such damage.

Component Failures

  • Failed relays or capacitors: Malfunctioning relays or capacitors on the control board can disrupt communication between components. Identifying and replacing faulty components can restore proper functionality.

7. Flame Sensor Problems

Carbon Buildup

  • Accumulated carbon on the flame sensor: Carbon buildup on the flame sensor can hinder its ability to detect the burner flame. Regular cleaning with a fine abrasive pad can resolve this issue as well as utilizing our furnace repair tips when needed.

Sensor Misalignment

  • Misaligned flame sensor: A misaligned sensor may not accurately detect the flame, leading to ignition failures. Proper positioning and securing of the flame sensor can address this problem.

8. Condensate Drain Issues


  • Blocked condensate drain line: Accumulated debris and algae can clog the condensate drain line, causing water backup. Regularly flushing the drain line helps prevent clogs and water damage.

Pump Failures

  • Malfunctioning condensate pump: A faulty pump can result in water overflow, potentially damaging the furnace. Testing and replacing the condensate pump as needed is crucial for preventing drainage problems.

9. Combustion Problems

Inadequate Combustion Air

  • Insufficient combustion air supply: Lack of proper ventilation can lead to incomplete combustion, producing carbon monoxide and potentially triggering safety shutdowns. Ensuring adequate ventilation resolves this issue.

Burner Issues

  • Dirty or misaligned burners: Burners covered in soot or out of alignment can lead to inefficient combustion. Regular cleaning and adjustment of the burners contribute to optimal furnace performance.

10. Excessive Cycling

Thermostat Calibration

  • Incorrect thermostat calibration: A miscalibrated thermostat can cause the furnace to cycle more frequently than necessary. Recalibrating or replacing the thermostat resolves this issue.

Airflow Restriction

  • Blocked return air ducts: Restricted airflow due to blocked return air ducts can force the furnace to cycle more frequently. Regularly cleaning and maintaining ducts ensures proper airflow.

11. Noisy Operation

Blower Wheel Issues

  • Misaligned or dirty blower wheel: A misaligned or dirty blower wheel can produce unusual noises during operation. Regular inspection and cleaning of the blower wheel address this issue.

Loose or Worn Parts

  • Loose or worn-out components: Parts such as belts, bearings, and pulleys can become loose or deteriorate, leading to noise issues. Tightening or replacing these components resolves the problem.

12. Overheating

Dirty Evaporator Coil

  • Accumulated dirt on the evaporator coil: Dirt on the evaporator coil impedes heat exchange, causing the furnace to overheat. Regular cleaning and maintenance prevent overheating due to a dirty coil.

High-Limit Switch Failures

  • Malfunctioning high-limit switch: A faulty high-limit switch may not shut off the furnace in cases of overheating. Replacing the high-limit switch ensures proper temperature regulation.

Tips for Furnace Maintenance this Thanksgiving

To ensure your furnace operates at peak performance and remains a reliable source of warmth during the cold months, regular maintenance is paramount. Consider these furnace maintenance tips as part of your Thanksgiving checklist:

  • Express Gratitude with a New Air Filter: Swap out your furnace air filter as a token of appreciation. A clean filter ensures optimal airflow, reducing the strain on your furnace. Make it a habit to replace the filter every 1-3 months.
  • Vent Appreciation: Show some love to your vents by checking and clearing them of any obstructions. Blocked vents can hinder airflow and diminish the efficiency of your furnace. A clear path ensures a warm and cozy home.
  • Feast on Professional Inspections: Consider scheduling a professional HVAC inspection during the Thanksgiving season. A certified technician can identify and address potential issues, giving you peace of mind as you enjoy your Thanksgiving festivities.
  • Thanksgiving Flame Sensor Cleanup: Take a moment to clean the flame sensor, ensuring it’s free from carbon buildup. A clean sensor promotes consistent ignition, making your furnace ready for the colder days ahead.
  • Grateful Condensate Drain Maintenance: Express gratitude to your condensate drain by keeping it clear and free-flowing. Regularly flush the drain line to prevent clogs and potential water damage.
  • Thermostat Harmony: Ensure harmony between your thermostat and your comfort preferences. Calibrate or replace the thermostat if needed, allowing you to celebrate Thanksgiving in a comfortably warm environment.
  • Ductwork Thankfulness: Show appreciation for your ductwork by inspecting and cleaning it periodically. A well-maintained duct system contributes to efficient airflow, maximizing the performance of your furnace.
  • Spread the Thanksgiving Joy: Keep your furnace’s moving parts well-lubricated. Regular lubrication reduces friction and extends the life of components like the blower motor.


Recognizing and addressing the various common failures of a furnace are essential for maintaining a reliable heating system this Thanksgiving. Regular inspections, proper maintenance, and timely repairs by the professionals at Einstein Heating and Cooling contribute to the longevity and efficiency of furnaces, ensuring they continue to provide warmth and comfort in the most demanding conditions. 

With these insights, may your Thanksgiving be filled not only with warmth but also with the reassurance that your home is well-equipped to handle the seasonal chill, allowing you to focus on the joyous moments that truly make this holiday special. 

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