Pilot Light Furnace Keeps Going Out

Pilot Light Furnace Keeps Going Out: Troubleshooting and Solutions

A flickering or extinguished pilot light on your furnace is a frustrating and potentially dangerous problem. It leaves your home vulnerable to cold temperatures and, if left unresolved, can lead to carbon monoxide buildup. This comprehensive guide will walk you through the common causes of a pilot light furnace constantly going out, offering practical troubleshooting steps and long-term solutions to keep your home warm and safe.

Understanding Your Furnace's Pilot Light System

Before diving into troubleshooting, let's understand how a pilot light system works. The pilot light provides a small, continuous flame that ignites the main burner when your thermostat calls for heat. This system relies on a delicate balance of gas flow, air intake, and proper ignition. Any disruption in this balance can result in a pilot light that keeps going out.

Key Components of a Pilot Light System:

• Gas Valve: Controls the flow of gas to both the pilot light and the main burner.
• Thermocouple: A small metal rod that generates a small electrical current when heated by the pilot flame. This current keeps the gas valve open.
• Pilot Assembly: Houses the pilot light, thermocouple, and gas valve components.
• Igniter: Provides the initial spark to light the pilot light (in some newer models).
• Air Intake: Allows for proper combustion of the gas.

Common Reasons Why Your Pilot Light Keeps Going Out

Several factors can cause your furnace's pilot light to repeatedly extinguish. Let's examine the most frequent culprits:

1. Insufficient Gas Supply

• Problem: A weak gas supply can prevent the pilot light from staying lit. This can be due to a clogged gas line, low gas pressure, or a problem with the gas meter itself.
• Troubleshooting: Check your gas meter to ensure it’s working correctly. Listen for any hissing sounds near the gas line; a faint whisper indicates a weak supply. If you suspect a blockage, contact a qualified gas technician immediately. Never attempt to repair gas lines yourself.

2. Dirty or Clogged Pilot Assembly

• Problem: Dust, dirt, debris, and cobwebs can accumulate in the pilot assembly, obstructing gas flow and preventing proper ignition.
• Troubleshooting: Turn off the gas supply to your furnace. Carefully remove the access panel to the pilot assembly. Use a soft brush or compressed air to gently clean the area around the pilot light, thermocouple, and gas valve. Pay close attention to any openings or orifices. Replace any visibly damaged or corroded components.

3. Faulty Thermocouple

• Problem: The thermocouple is a critical component. If it's damaged or dirty, it may not generate enough electricity to keep the gas valve open, causing the pilot light to extinguish.
• Troubleshooting: Visually inspect the thermocouple for any signs of damage, such as cracks, bends, or corrosion. Clean it carefully with fine steel wool. If it's visibly damaged, it needs to be replaced. This is a job best left to a qualified technician.

4. Weak or Damaged Pilot Burner

• Problem: A weak or damaged pilot burner may not produce enough heat to keep the thermocouple energized.
• Troubleshooting: Examine the pilot burner for any cracks, holes, or obstructions. If damaged, it needs to be replaced. Again, professional assistance is recommended here.

5. Blocked Air Intake

• Problem: Sufficient airflow is crucial for combustion. Obstructions like dust, debris, or even a nearby object blocking the air intake vents can lead to pilot light failure.
• Troubleshooting: Check the air intake vents for any obstructions. Clean them thoroughly to ensure proper airflow.

6. Improper Pilot Light Adjustment

• Problem: The pilot light flame might be too small or too large. A small flame may not provide enough heat to the thermocouple, while a large flame could be inefficient and lead to problems.
• Troubleshooting: Consult your furnace's owner's manual for instructions on adjusting the pilot light flame. It should be a small, steady blue flame. Adjustments require caution and precision; if unsure, seek professional help.

7. Draft Issues

• Problem: A strong draft can blow out the pilot light. This is more common in older furnaces or those located in drafty areas.
• Troubleshooting: Check for any drafts near the furnace. Seal any gaps or cracks around the furnace to prevent drafts.

8. Low Gas Pressure in the Line

• Problem: If the gas pressure to the furnace is consistently low, it can prevent the pilot light from staying lit. This is less common but should be considered if other causes have been ruled out.
• Troubleshooting: Contact your gas company to have them check the gas pressure at your meter.

9. Problems with the Gas Valve

• Problem: A malfunctioning gas valve may fail to supply enough gas to the pilot light, even if the gas supply and pressure are adequate.
• Troubleshooting: This is a complex component and requires expertise to diagnose and repair. Always call a qualified technician for gas valve issues.

Preventing Future Pilot Light Extinctions

Once you've addressed the immediate problem, take steps to prevent it from recurring:

• Regular Maintenance: Schedule annual furnace inspections and maintenance by a qualified HVAC technician. This includes cleaning the pilot assembly and checking all components.
• Keep the Area Clean: Dust and debris can accumulate quickly. Regularly clean the area around your furnace to prevent obstructions.
• Check for Drafts: Seal any gaps or cracks around your furnace to minimize drafts.
• Monitor Gas Supply: If you suspect low gas pressure, contact your gas company.
• Replace Worn Components: Don't hesitate to replace worn or damaged parts, such as the thermocouple or pilot burner. Investing in replacements prevents more costly repairs down the line.

When to Call a Professional

While some troubleshooting can be done at home, certain repairs should always be left to qualified professionals. Never attempt to repair gas lines or components yourself. Contact a licensed HVAC technician if:

• You suspect a gas leak.
• You're unsure about any repair or adjustment.
• The problem persists after attempting basic troubleshooting.
• You're uncomfortable working with gas appliances.

Ignoring a malfunctioning furnace can be dangerous. A properly functioning heating system is crucial for your comfort and safety. By understanding the common causes of a pilot light going out and taking preventative measures, you can keep your home warm and your family safe. Remember, when in doubt, always call a professional. The cost of a service call is far less than the potential consequences of a gas leak or carbon monoxide poisoning.