What Causes Furnace Pilot Light to Keep Going Out?

If you’ve noticed your furnace’s pilot light repeatedly going out, you’re not alone. This common issue can cause a lot of frustration, especially during the colder months when a reliable heat source is crucial. Understanding the potential causes can help you address the issue quickly and prevent future problems.

1. Dirty Pilot Light or Flame Sensor

Over time, dirt and dust can accumulate on the pilot light or the flame sensor, preventing the flame from staying lit. A dirty flame sensor may not be able to detect the flame, causing the furnace to shut off.

How this affects performance:

Frequent shutdowns: If the pilot light doesn’t stay on, your furnace can’t provide heat, leading to discomfort.

Increased wear on parts: The furnace may attempt to reignite multiple times, which can lead to increased wear on the ignition components.

What to do:

Clean the pilot light and flame sensor carefully. You may need to turn off the gas supply and use a soft brush or compressed air to remove dirt or debris.

2. Faulty Thermocouple

The thermocouple is a safety device that detects whether the pilot light is on. If the thermocouple is faulty, it will signal that the pilot light is out, even if it’s not, and the furnace will shut down.

How this affects performance:

Frequent pilot light outages: A malfunctioning thermocouple can cause the pilot light to go out repeatedly.

Inconsistent operation: The furnace may not turn on at all if the thermocouple is damaged.

What to do:

If the thermocouple is defective, it will need to be replaced. A professional HVAC technician can easily perform this repair.

3. Gas Supply Issues

If there’s a problem with the gas supply, the pilot light may not stay lit. Issues such as a clogged gas line, low gas pressure, or a closed gas valve can prevent the furnace from getting the proper fuel needed for combustion.

How this affects performance:

Pilot light goes out regularly: Insufficient or interrupted gas supply can prevent the pilot light from staying on.

Increased wear on the system: A furnace struggling to ignite due to gas flow issues will cause unnecessary stress on the system.

What to do:

Check that the gas valve is open, and there are no leaks or blockages in the gas line. If you suspect a gas supply issue, contact a licensed technician for a thorough inspection.

4. Drafts or Airflow Problems

Strong drafts near the furnace or issues with airflow can blow out the pilot light. If the furnace is located in a drafty area, such as near a window or door, it may cause the pilot to flicker or go out.

How this affects performance:

Pilot light blows out: Drafts can disturb the pilot flame, causing it to go out.

Inconsistent heating: If the pilot light keeps going out, your furnace won’t be able to heat the home effectively.

What to do:

Ensure that your furnace is located away from direct airflow sources like open windows or vents. Sealing any drafts around the furnace area can help prevent this issue.

5. Malfunctioning Gas Valve

The gas valve controls the flow of gas to the pilot light and burner. If the valve malfunctions, it can cut off the gas supply or deliver insufficient gas, leading to the pilot light going out.

How this affects performance:

Failure to stay lit: A malfunctioning gas valve can prevent the pilot light from staying on.

Risk of a larger failure: If the gas valve continues to malfunction, it can cause further problems with your furnace, leading to costly repairs.

What to do:

Have the gas valve inspected and repaired or replaced by a professional if necessary.

6. Dirty or Faulty Furnace Components

Other components within the furnace, such as the burner or ignition system, can also contribute to pilot light issues. Over time, components wear down or get clogged with dirt, which can affect the ignition process.

How this affects performance:

Inconsistent performance: If components aren’t functioning properly, the furnace may struggle to ignite, leading to repeated pilot light outages.

System stress: The furnace may make multiple attempts to ignite, which can stress the system and lead to more significant issues down the line.

What to do:

Schedule regular furnace maintenance to clean and inspect all components, ensuring the system is functioning efficiently.

Why Smile HVAC?

At Smile HVAC, Toronto's Best HVAC Service Company, we prioritize your comfort and peace of mind by offering reliable, top-quality HVAC services tailored to meet your specific needs. With years of experience serving Canadian homes, our team of certified professionals ensures expert installation, maintenance, and repairs using the latest technology and energy-efficient solutions. We pride ourselves on excellent customer service, transparent pricing, and fast response times, making us the trusted choice for all your heating and cooling needs. Choose Smile HVAC for a service that delivers comfort, savings, and a smile every time.

Our Service Locations

Furnace Repair Durham

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Conclusion

A pilot light that keeps going out can be caused by several issues, ranging from a dirty flame sensor to a malfunctioning gas valve. Identifying the root cause and addressing it promptly can save you from further system failures and costly repairs. If you're unable to resolve the issue on your own, it’s best to contact a professional HVAC technician for a thorough inspection and repair. Regular maintenance can help prevent these types of issues and keep your furnace operating efficiently.