Furnace Main Burner Shuts Off After Ignition: What’s Causing It

furnace main burner shuts off after ignition

Ensure your heating system reaches its optimal efficiency level with JC Mechanical. Call (720) 372-0944 today!

Your furnace keeps your home warm and comfortable during Colorado’s frigid winter season. However, sometimes, furnaces experience issues that prevent their burners from operating properly, causing them to shut off before adequately heating Centennial residents’ homes. To help you determine why your furnace’s main burner shuts off after ignition,  our team at JC Mechanical put together a few potential causes and how they affect your unit.

JC Mechanical is one of Centennial, Colorado’s leading professional heating and cooling companies. If you need a reliable furnace repair service in Centennial, CO, to breathe new life into your heating system, contact our experienced technicians. 

Six Reasons Why Your Furnace’s Main Burner Shuts off After Ignition

Furnaces are complex machines featuring numerous mechanisms that work together to ensure optimal operations. However, if one of these components breaks down, it can bring the unit’s performance to a screeching halt. 

Unfortunately, identifying the source of a faulty main burner isn’t always easy since several malfunctions can prevent it from working correctly. Everything from safety features to dirty burners can hinder operations, leaving your property exceedingly cold until you repair the system. Once you understand the primary causes, you can determine why your furnace’s main burner shuts off after ignition and resolve it without delay.

Below are a few common causes of malfunctioning furnace burners.

1. A Dirty or Broken Flame Sensor 

A furnace’s flame sensor (called a thermocouple in gas furnaces with pilot lights) signals the control board to produce warm air once it senses a flame. However, sometimes, the flame sensor becomes dirty and can’t detect the furnace’s flame, causing the furnace to shut down to prevent combustion chamber flooding. 

Cleaning the sensor will allow it to identify the furnace’s flame more efficiently and restore the unit’s performance. Dust, dirt, and grime often accumulate on the sensor and other internal components over time, so regularly cleaning your unit will help maintain its performance and heating quality. However, if the sensor can’t sense the flame after a thorough cleaning, you may need to contact a technician to replace it.

2. Malfunctioning Pressure Switch

The pressure switch activates and keeps the burners ignited once the unit has enough air passing through it. However, insufficient airflow will prevent the pressure switch from turning on, preventing the burner from igniting. Having sufficient airflow is essential for a furnace to maintain operations and will cause several issues without it.

Restoring or improving airflow in and around your furnace will resolve most pressure switch issues, allowing it to ignite the burner. It’s best to contact a professional technician to assess your unit and determine if it’s in a suitable area. If they believe its current location doesn’t have enough airflow to maintain proper operations, they will move it to a new location.

3. Faulty Control Board

When your furnace’s main burner shuts off after ignition, it could be due to a faulty control board.

Think of the control board as the brain of your furnace. It sends and receives information to ensure everything functions properly. If the control board malfunctions, it can’t transmit commands to other components, causing the furnace to break down.

Replacing the furnace’s control board will allow it to transfer information and ignite the main burner.

4. Draft Inducer Motor Issues

The draft inducer motor pulls air into your furnace and activates the pressure switch to ignite the burner. It also pushes air through the burner, ensuring it has enough oxygen to stay lit. A malfunctioning draft inducer motor will limit airflow and cause numerous malfunctions that significantly reduce the furnace’s efficiency.

Repairing or replacing the draft inducer motor will allow the furnace to draw in more air and help the components perform their duties. Every furnace needs sufficient airflow to function, making the draft inducer motor a key element in your unit’s operations.

5. Broken Flame Rollout Switch

A furnace’s flame rollout switch controls the burner’s temperature and shuts down the furnace if it gets too hot. It’s a safety feature that prevents the unit from catching fire if the unit’s interior overheats. 

Flame rollout switch issues stem from numerous problems ranging from a lack of airflow due to dirty air filters to flue malfunctions. A heating specialist will identify the issue and determine the best solution to restore your unit’s performance. 

6. Dirty Burners

Like flame sensors, furnace burners become dirty and can’t obtain enough oxygen to ignite. Dirt, dust, grime, and other pollutants create a layer of filth over the burner that prevents air from reaching it, causing the unit to shut down. Scheduling routine furnace maintenance is a surefire way to avoid dirty burners and keep them running optimally throughout the year.

It’s important to note that you shouldn’t attempt to clean your furnace’s burners. It requires you to detach the burner assembly and is exceedingly complicated if you don’t have the necessary training. Always contact a professional heating and cooling company to clean your furnace’s burner and maintain your unit’s interior.

Many burner ignition issues stem from poor airflow and a lack of maintenance. Keeping up with your furnace’s maintenance demands is the best way to prevent malfunctions and ensure it operates efficiently year-round. A professional technician will clean the unit, make slight performance adjustments, and fix any problems before they affect your system.

Our team has fixed and maintained furnaces for over 30 years and will keep yours in immaculate condition for a price that won’t burden your budget.

Contact JC Mechanical for First-Class Furnace Repair and Maintenance Services in Centennial, Colorado

If your furnace’s main burner shuts off after ignition and requires professional servicing, contact the heating experts at JC Mechanical. Our team will have your furnace up and running again using the best repair and maintenance methods in the industry today. Whether you need help installing a new furnace in an old house or need to replace the gas valve, our technicians are here to help.

Give us a call at 720-372-0944 and schedule your appointment in Centennial, Colorado, today!

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