How to Relight Pilot Light on Furnace: A Step-by-Step Guide

Is your house feeling a bit too much like an icebox? A common culprit for a chilly home, especially during the colder months, is a furnace with a pilot light that has gone out. While newer furnaces often have electronic ignition, many older models still rely on a small, constant flame called a pilot light to ignite the main burners. A pilot light can extinguish for various reasons, from a draft to a gas supply interruption, leaving you without heat. Ignoring a pilot light issue can lead to discomfort, frozen pipes, and even potential safety hazards if unburnt gas accumulates.

Knowing how to safely relight your furnace pilot light is a valuable skill for any homeowner. It can save you from costly service calls and restore heat to your home quickly. However, safety is paramount when dealing with gas appliances. It’s crucial to understand the correct procedure and potential risks before attempting to relight the pilot. This guide will walk you through the steps to safely relight your pilot light, but if you are ever unsure or uncomfortable, always call a qualified HVAC technician.

What are common causes of a pilot light going out, and how do I prevent them?

What safety precautions should I take before attempting to relight the furnace pilot light?

Before attempting to relight your furnace pilot light, ensure the area is well-ventilated to prevent gas buildup, turn off the gas supply to the furnace, wait several minutes for any accumulated gas to dissipate, and have a working flashlight to see clearly. Double-check that the gas valve is in the “off” position before you start.

Relighting a pilot light can be risky if proper precautions aren’t taken. The primary hazard is the potential for gas accumulation, which can lead to a flash fire or even an explosion. This is why ventilation is crucial; open windows and doors to allow any lingering gas to escape. Waiting several minutes after turning off the gas valve gives the gas time to dissipate. Never introduce a flame source, such as a match or lighter, into the vicinity before thoroughly ventilating the area. Moreover, working in a dimly lit furnace area significantly increases the risk of errors. A flashlight provides the necessary visibility to identify the pilot light assembly, locate the gas valve, and carefully observe the relighting process. A hands-free flashlight or headlamp is highly recommended to allow for greater dexterity. Finally, ensure you know the exact location of the gas shut-off valve for your entire house in case the pilot light relighting attempt goes wrong, so you can quickly cut off the gas supply.

Where exactly is the pilot light located on my furnace model?

The pilot light location varies depending on your furnace model, but it’s generally found inside the burner compartment, near the gas valve and main burner assembly. Look for a small metal assembly with a tiny opening where the flame should be present. Often, there’s a label or diagram near the gas valve indicating its precise location.

For a more precise location, consult your furnace’s owner’s manual. If you don’t have the manual, search online using your furnace’s model number (usually found on a sticker on the furnace itself). The manual will provide a diagram or clear instructions showing the exact placement of the pilot light assembly. Common locations include behind a small access panel within the burner compartment or positioned centrally amongst the burners. Older models might have a slightly more hidden pilot light assembly compared to newer, more accessible designs. If you still can’t find it, try shining a flashlight into the burner compartment and looking for the gas valve. The pilot light assembly will almost always be directly connected to or very near the gas valve. Remember to always turn off the gas supply to the furnace before attempting to locate or relight the pilot, ensuring you follow all safety precautions outlined in your manual or by a qualified HVAC technician.

What do I do if the pilot light won’t stay lit after following the instructions?

If the pilot light repeatedly fails to stay lit after following the manufacturer’s instructions, the most common culprits are a dirty or faulty thermocouple/thermopile, a blocked pilot orifice, or a gas supply issue. It’s crucial to address these possibilities systematically, but safety should always be your top priority. If you’re uncomfortable working with gas appliances, contact a qualified HVAC technician.

A dirty or failing thermocouple/thermopile is the most frequent reason a pilot light won’t stay lit. The thermocouple/thermopile is a safety device that senses the heat from the pilot flame and allows the main gas valve to open. If it’s coated in soot or malfunctioning, it won’t generate enough voltage to keep the gas valve open. Try gently cleaning the thermocouple with fine steel wool or sandpaper to remove any buildup. If cleaning doesn’t work, it likely needs to be replaced. Similarly, a blocked pilot orifice restricts the gas flow to the pilot light, causing it to be weak or nonexistent. This requires careful cleaning using a thin wire or specialized pilot cleaning tool; avoid enlarging the orifice, as this can create a dangerous situation. Before proceeding, double-check that the gas supply to the furnace is turned on. Also, ensure that there isn’t excessive air in the gas line, which can occur after a gas shut-off. If you suspect air in the line, contact your gas company. If you’ve checked these things and the pilot still won’t stay lit, there could be more complex issues, such as a faulty gas valve or problems with the furnace’s control board. These problems require professional diagnosis and repair. It’s advisable to contact a licensed HVAC technician to thoroughly inspect the furnace and perform the necessary repairs to ensure safe and reliable operation.

How long should I hold the gas valve button down while relighting the pilot?

You should typically hold the gas valve button down for 20-30 seconds after lighting the pilot. This allows the thermocouple to heat up sufficiently and prove to the gas valve that the pilot flame is present, preventing it from shutting off the gas supply.

Holding the button down for the correct duration is crucial for a successful pilot light relighting. The thermocouple is a safety device that generates a small electrical current when heated by the pilot flame. This current signals the gas valve to remain open, continuously supplying gas to the pilot. If you release the button too early, the thermocouple won’t be hot enough to generate the necessary current, and the gas valve will close, extinguishing the pilot. If the pilot light doesn’t stay lit after holding the button for 30 seconds, try again. Ensure the flame is consistently engulfing the thermocouple. If it still fails to stay lit after several attempts, there may be an issue with the thermocouple itself, the gas valve, or the gas supply. In such cases, it’s best to consult a qualified HVAC technician for diagnosis and repair. Do not continue attempting to relight the pilot if you suspect a gas leak or smell gas, evacuate the area immediately and call your gas company.

What does a properly lit pilot light flame look like?

A properly lit pilot light flame should be a strong, steady blue flame, typically with a pointed tip. It should completely engulf the thermocouple or flame sensor, ensuring consistent heating and reliable operation of the main burner.

A healthy blue flame indicates complete combustion of the gas. It is vital that the flame is robust enough to consistently heat the thermocouple or flame sensor. This component generates a small electrical current that tells the gas valve it’s safe to open and supply gas to the main burner. If the flame is weak, yellow, flickering, or doesn’t fully envelop the sensor, it may not provide sufficient heat, leading to the furnace shutting down unexpectedly or failing to ignite the main burner. Several factors can influence the appearance of the pilot light flame. A dirty pilot light orifice, insufficient gas pressure, or drafts can all contribute to a weak or irregular flame. If the flame is yellow or orange, it indicates incomplete combustion, which could be due to a lack of oxygen or contaminants in the gas line. Addressing these issues is crucial for ensuring efficient and safe furnace operation. Consult a qualified HVAC technician if you are uncomfortable troubleshooting potential problems.

Is it safe to repeatedly try to relight the pilot if it keeps going out?

No, it is generally not safe to repeatedly try to relight a furnace pilot light that consistently goes out. Repeated attempts can lead to a dangerous accumulation of gas, increasing the risk of an explosion or fire. It’s crucial to identify and address the underlying cause of the pilot light extinguishing instead of continuously trying to reignite it.

Repeatedly attempting to light the pilot light without understanding why it’s failing bypasses crucial safety mechanisms. Furnaces are designed with sensors that shut off the gas supply if the pilot light isn’t detected. When you keep trying to relight it, you’re essentially overriding this safety feature. If there’s a leak or another problem preventing the pilot from staying lit, you’re saturating the area with unburned gas each time you try. This creates a highly flammable environment and a serious hazard. Instead of repeated attempts, prioritize diagnosing the problem. Common reasons for a pilot light to extinguish include a dirty or faulty thermocouple, a blocked pilot light orifice, a draft blowing out the flame, or a problem with the gas supply. A qualified HVAC technician should be called in to inspect the furnace and safely resolve the issue. They have the tools and expertise to identify gas leaks and repair or replace malfunctioning components. Delaying this can potentially save lives and money.

When should I call a professional instead of attempting to relight the pilot light myself?

You should call a professional HVAC technician immediately if you smell a strong odor of gas, suspect a gas leak, are uncomfortable working with gas appliances, have difficulty locating the pilot light assembly or gas valve, or if the pilot light repeatedly goes out after you’ve successfully relit it.

Relighting a pilot light can seem straightforward, but safety should always be your top priority. The presence of a strong gas odor suggests a leak, and attempting to relight the pilot in such a situation could trigger an explosion. Evacuate the area immediately and call your gas company or fire department from a safe distance. Even if the smell is faint, proceed with extreme caution. If you are at all uneasy about handling gas or electrical components, or if you can’t confidently identify the pilot light assembly and gas valve, it’s best to err on the side of caution and let a qualified technician handle the task. A pilot light that repeatedly goes out after being relit indicates an underlying problem that needs professional attention. This could be due to a faulty thermocouple, a dirty pilot light orifice, or a more serious issue with the gas valve or furnace controls. Continuing to relight the pilot light without addressing the root cause is not only frustrating but also potentially dangerous, as it could lead to carbon monoxide buildup or even a fire. A technician can diagnose the problem and make the necessary repairs to ensure your furnace operates safely and efficiently.

And there you have it! Hopefully, your furnace is now humming along, keeping you warm and cozy. Thanks for sticking with me, and feel free to pop back any time you’ve got a household hiccup – I’ll do my best to help you troubleshoot!