HOW TO RELIGHT THE STANDING PILOT LIGHT ON A GAS FURNACE: WHY PROFESSIONAL SERVICE MATTERS
The standing pilot light is a familiar feature for many homeowners with older gas furnaces. This small, ever-burning flame ignites the burners when your thermostat demands heat. While the technology is reliable, it’s not without its quirks. A pilot light can go out for various reasons, leaving your home without heat until safely relit. While relighting a pilot light may seem like a simple task, there are important reasons why calling a professional HVAC technician is the safest and most effective approach.
Understanding the standing pilot light
The standing pilot light is a legacy technology found in older furnaces, typically those with an annual fuel utilization efficiency (AFUE) rating below 80%. Unlike modern electronic ignition systems, which only spark when needed, the standing pilot burns continuously. Its job is to ignite the main burners when the furnace cycles, ensuring your home stays warm during cold weather.
If the pilot light goes out, the furnace’s burners won’t ignite, and your heating system will stop working. A safety device called a thermocouple detects whether the pilot is lit to prevent gas from accumulating. If the thermocouple senses no flame, it automatically shuts off the gas supply to the burners, protecting your home from dangerous gas leaks.
Why does the pilot light go out?
There are several reasons a standing pilot light might extinguish:
Drafts or sudden gusts of air, especially in basements or poorly insulated spaces.
A malfunctioning or dirty thermocouple can mistakenly shut off the gas supply.
Dirt, dust, or debris accumulate around the pilot assembly, weakening the flame or blocking gas flow.
Fluctuations in gas pressure or air in the gas line can interrupt the steady flow of fuel.
Moisture or condensation inside the furnace, which can extinguish the flame.
Intentional shut-off by homeowners during the off-season to save energy.
Regardless of the cause, a pilot light that goes out will render your furnace inoperable until properly relit.
Why professional service is the best choice
While it’s possible to find step-by-step guides for relighting a pilot light, there are compelling reasons to let a qualified HVAC technician perform this task:
Ensuring safety
Working with natural gas or propane always carries a risk. Even a small mistake can lead to gas leaks, fire hazards, or dangerous carbon monoxide exposure. Professionals can recognize and mitigate these risks. They know how to safely inspect for gas leaks, ensure proper ventilation, and follow manufacturer procedures for your specific furnace model.
Diagnosing underlying issues
A pilot light that repeatedly goes out is often a symptom of a deeper problem. A professional technician will relight the pilot and diagnose and address the root cause. This might include:
Cleaning or replacing a dirty or malfunctioning thermocouple.
Clearing debris from the pilot assembly.
Adjusting the gas pressure or checking for supply issues.
Inspecting cracks, corrosion, or other signs of wear in the heat exchanger or burner assembly.
A professional can identify and fix the underlying issue, helping prevent future outages and extend the life of your furnace.
Protecting your investment
Furnaces are a significant investment. Improper handling or repeated DIY attempts to relight the pilot can cause further damage, void warranties, or lead to costly repairs. HVAC professionals have the tools, training, and experience to ensure the job is done right the first time, protecting your equipment and your wallet.
Maintaining efficiency and performance
A properly functioning pilot light is essential for efficient furnace operation. If the flame is weak, yellow, or flickering, it can lead to incomplete combustion, reduced heating performance, and increased energy bills. A professional technician will ensure the pilot flame burns cleanly and at the correct intensity, optimizing your furnace’s performance and energy efficiency.
Ensuring code compliance
Gas appliances are subject to local building codes and safety regulations. Professional HVAC technicians know these requirements and will ensure that any work performed on your furnace is fully compliant. This is especially important if you plan to sell your home or need to provide proof of professional maintenance for insurance purposes.
Recognizing signs of pilot light problems
If your furnace isn’t producing heat, the pilot light is often the first thing to check. Other signs of pilot light issues include:
The furnace runs but doesn’t produce warm air.
The pilot flame is weak, yellow, or flickering instead of strong and blue.
The pilot light won’t stay lit, even after relighting.
There’s a persistent smell of gas near the furnace.
Your energy bills are higher than normal, suggesting the furnace runs inefficiently.
If you notice any of these signs, it’s time to call a professional for a thorough inspection and service.
What a professional service visit includes
When you call a licensed HVAC technician to address a pilot light issue, you can expect a comprehensive service visit beyond simply relighting the flame. Here’s what a typical appointment might involve:
Safety inspection: The technician will check for gas leaks, proper ventilation, and any signs of carbon monoxide.
Pilot assembly cleaning: Any dirt or debris around the pilot orifice will be carefully removed to ensure a strong, stable flame.
Thermocouple testing: The thermocouple will be inspected for alignment, cleanliness, and proper function, and replaced if necessary.
Gas pressure check: The technician will verify that the gas pressure is within manufacturer specifications.
Burner and heat exchanger inspection: The overall condition of the furnace, including the burners and heat exchanger, will be assessed to identify any signs of wear, corrosion, or cracks.
Relighting and adjustment: The pilot light will be safely relit, and the flame will be adjusted to ensure optimal performance.
System test: The technician will run the furnace through a complete cycle, checking for proper ignition, burner operation, and overall system performance.
The importance of regular professional maintenance
Even if your furnace seems to be running well, regular professional maintenance is essential for safe and efficient operation. Annual service visits can catch minor issues before they become big problems, extend the life of your furnace, and help ensure your home stays warm all winter. During a maintenance visit, your technician will:
Clean and inspect the pilot assembly and burners.
Test the thermocouple and other safety devices.
Check for gas leaks and proper ventilation.
Inspect and lubricate moving parts as needed.
Verify that your system is operating at peak efficiency.
The risks of DIY pilot relighting
While relighting the pilot light yourself may be tempting, the risks often outweigh the rewards. You could inadvertently create a hazardous situation without the proper tools, knowledge, and safety training. Some potential dangers include:
Failing to detect a gas leak before lighting the pilot could result in an explosion or fire.
Damaging the thermocouple or pilot assembly, leading to more frequent outages or costly repairs.
Misadjusting the flame, resulting in incomplete combustion and increased carbon monoxide production.
Voiding your furnace’s warranty by performing unauthorized repairs or adjustments.
When to consider furnace replacement
If your furnace is more than 15 or 20 years old and experiencing frequent pilot light issues, it may be time to consider a replacement. Newer furnaces use electronic ignition systems that are more reliable, efficient, and safer than standing pilot lights. Upgrading to a modern system can improve comfort, lower energy bills, and provide peace of mind.
The standing pilot light is a critical component of many older gas furnaces, but when it goes out, it can leave your home without heat and pose potential safety risks. While relighting a pilot light might seem simple, the safest and most effective approach is to call a professional HVAC technician. Professionals don’t just relight the flame—they inspect your system for underlying issues, ensure safe operation, and help maintain your furnace’s efficiency and longevity. Regular professional maintenance and prompt attention to pilot light problems will keep your home warm, safe, and comfortable throughout the heating season. If you’re experiencing issues with your furnace’s pilot light, don’t hesitate to contact a trusted HVAC service provider for expert assistance.
If you need experienced and trained technicians for furnace installation, furnace maintenance, furnace replacement, and furnace repair, contact Above and Beyond Air Conditioning & Heating at (210)794-9895. Emergency services are available 24/7.
