Fix a gas furnace pilot light that won’t stay lit in just a few steps

If your gas furnace pilot light keeps going out, it can be frustrating, and chilly! But don’t worry, you can fix this issue yourself with a few simple troubleshooting steps. We’ll walk you through some common causes and easy fixes so you can get your furnace up and running again in no time.

Note: The information provided in this article may not apply to your specific appliance model. While we strive to offer helpful advice for DIY appliance repairs, variations in models and configurations can lead to differences in troubleshooting steps, error codes, and part replacements. For the most accurate guidance, we strongly recommend consulting the technical sheet for your specific appliance model.

Safety precautions   

Safety should always be a priority when working on any appliance. Here are a few practical tips to help you stay safe:

• Turn off the power to the appliance by unplugging it or switching off the circuit breaker before starting any maintenance or repairs. This protects you from the risk of electric shock.
• Wear insulated gloves to shield your hands from sharp edges, pinching hazards, or debris.
• Work at a steady pace and take your time to avoid accidents or injuries.
• Make sure your workspace is well-lit so you can clearly see and access the parts you’re working on.
• Keep the area clear of clutter, and ensure children and pets stay out of the workspace.
• Never handle internal parts with wet hands. Check that both your hands and the work area are completely dry.
• Refer to your appliance’s user manual for any specific instructions or safety guidelines related to the part or repair.
• Handle parts gently to avoid damage to the appliance or potential injuries from applying too much force.
• Use safety glasses when dealing with chemicals, dust, or large debris to protect your eyes from harm.
• If the appliance was recently used, give it enough time to cool down before working on any heated components.
• Take photos or notes of wiring connections and terminals before disconnecting anything to make reassembly easier.
• Avoid touching exposed wires or terminals. If you must handle wires, use non-conductive tools or wear insulated gloves to minimize the risk of electrical shock.

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Dirty or clogged pilot light orifice

Over time, the pilot light orifice can get clogged with dirt, dust, or other debris, which obstructs the gas flow and prevents the flame from staying lit. This is a common issue, and it usually happens because dust, dirt, or even spider webs accumulate in the orifice, blocking the flow of gas. Here’s how to fix it:

1. Turn off the furnace and gas supply to ensure your safety.
2. Locate the pilot light and orifice on your furnace. You might need to remove a cover or panel to access it.
3. Use a small brush or compressed air to clean around the pilot light and orifice, making sure there’s no dirt or debris blocking the gas flow.
4. Use a small needle or wire to gently clear any clogs in the pilot orifice. Be careful not to damage it.
5. After cleaning, try relighting the pilot light. Follow the instructions in your furnace manual for proper lighting procedures.

Thermocouple issues

A faulty thermocouple can cause the pilot light to go out. The thermocouple is a safety feature that detects whether the pilot light is on. If it malfunctions or gets dirty, it can cause the gas valve to shut off the gas supply, making it impossible for the pilot light to stay lit. Here’s how to fix it:

1. Turn off the furnace and gas supply to ensure safety.
2. Locate the thermocouple, which is usually positioned near the pilot light.
3. Inspect the thermocouple for signs of wear, dirt, or corrosion. If it’s dirty, use a soft cloth to clean it.
4. If the thermocouple looks damaged or worn out, it may need to be replaced. Be sure to get the correct replacement part for your furnace model.
5. Use a multimeter to test the thermocouple’s resistance. If the reading is outside the normal range specified in your furnace manual, the thermocouple is likely faulty and should be replaced.
6. Once cleaned or replaced, reassemble everything, turn the gas back on, and try relighting the pilot light.

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Gas supply issues

If there’s an issue with the gas supply, it can prevent the pilot light from staying lit. The gas valve may not be fully open, or there could be a blockage in the gas line that disrupts the flow of gas to the pilot light. Here’s how to check it:

1. Make sure the gas valve is fully open. The valve handle should be parallel to the gas line when it’s open. If it’s turned perpendicular, rotate it to open the valve.
2. Inspect the gas line for any kinks or visible damage. If you see any issues or smell gas, leave the area immediately and contact your gas company for help.
3. If everything looks good, check that the gas line is clear and not blocked.

Bad gas valve

A malfunctioning gas valve can cause the pilot light to go out because it controls the gas flow to the pilot light. If the valve is faulty, it may not open or close properly, preventing the pilot light from staying lit. Here’s how to check it:

1. Turn off the furnace and gas supply before you begin working on the gas valve.
2. Inspect the gas valve for any visible signs of damage, such as leaks or corrosion. If you notice any issues, the valve may need to be replaced.
3. You can test the gas valve with a multimeter to check its functionality. Set your multimeter to measure continuity or resistance and test the valve’s terminals. 
4. If the resistance is outside the normal range (which should be listed in your furnace manual), the valve is likely faulty and needs replacement.

Read more: 12 simple space heater safety tips for this winter

Additional information

Thanks for reading! If you need replacement parts, grab your model number and head to AppliancePartsPros.com. We offer over two million parts and most orders arrive in two business days. If you need help finding the right part or placing an order, you can contact our team at 1 (877) 477-7278.

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