If your pilot light won’t stay lit, the most common culprit is a dirty or faulty thermocouple (the small metal rod next to the flame that signals the gas valve to stay open). To fix it: hold the gas knob down longer, clean or replace the thermocouple, or clear a blocked pilot tube.
Clogged Pilot Tube
Dust, soot, or corrosion blocks the narrow pilot tube where gas exits. The blockage reduces flame size and stops it from heating the thermocouple properly. Cleaning the tube with a fine wire or compressed air restores correct gas flow and consistent ignition.
Freestanding Gas Range models with an oven pilot ignition have a 1/8" flame. The amount of gas furnished to burn the oven pilot is minimal. If the pilot should go out, gas is immediately shut off to the main burner. However, there is still a small amount of gas that will continue to flow to the oven pilot.
6 Common Reasons Your Pilot Light Keeps Going Out
If a new thermocouple fails to keep the pilot lit, the sensor tip is likely misaligned, the connection to the gas valve is loose, or the pilot orifice is blocked. The thermocouple must generate a tiny electrical current to hold the safety valve open.
Replacing a thermocouple is a relatively easy fix that can take less than two hours. This guide reviews how to replace a thermocouple to ensure gas appliances stay in good working order, as well as how to relight a pilot light.
On average, professional replacement costs can range from $100 to $300 or more, depending on these factors. 3.
Your pilot light can go out for many reasons: a faulty thermocouple, airflow issues, gas supply hiccups, or dirty parts.
Common Signs of a Bad Furnace Thermocouple
Pilot Light Issues: The pilot light may go out due to a blocked or damaged thermocouple. Relighting is typically inexpensive unless the thermocouple requires replacement, which can range between $120 and $300.
It's sometimes called the “flame sensor.” It shuts the gas off if the pilot goes out. Gas that flows through your furnace could enter your house if the thermocouple fails to turn it off. Protecting your home from gas buildup is the thermocouple.
A gas oven igniter replacement costs $150 to $350 on average, depending on your appliance's make, model, and whether you do it yourself or hire a professional.
Your gas fireplace could be turning off for several reasons. The most like culprits are likely tied to some kind of problem with your setup. Anything from issues with your pilot light, clogged ports on burners, damage to heating components, and thermocouple/thermopile malfunctions can be to blame.
If your pilot light won't stay lit, the most probable cause is a faulty, dirty, or misaligned thermocouple. The thermocouple is a safety sensor that detects the flame; when heated, it signals the gas valve to stay open. If it can't sense the heat, it shuts off the gas to prevent leaks.
High gas pressure in a furnace ("over-firing") causes it to run too hot, resulting in inefficient combustion, short cycling, and damage to components. This can cause the unit to trigger its high-limit switch, shut down to prevent fires, or create excessive soot and carbon monoxide.
A healthy pilot flame should be a crisp, steady blue, engulfing the top third of the thermocouple. A weak, yellow, or wavering flame often indicates a dirty pilot orifice or a gas supply issue, preventing the thermocouple from getting hot enough to function.
A bad gas valve typically shows itself through furnace ignition failures, inconsistent heating, or dangerous gas leaks. Key indicators include your furnace clicking but failing to light, weak or uneven flames, short-cycling, or the distinct smell of natural gas.
On average, the furnace gas valve replacement cost you can expect to pay will be between $200 and $800. This range accounts for the cost of the part itself as well as the labor needed for installation. The cost of the part varies based on the valve's brand, size, and type.
1. The pilot light won't stay lit. The main issues that keep a pilot light from staying lit are a dirty or damaged thermocouple, a clogged or damaged gas tube, or a faulty pilot control knob. If the thermocouple is damaged or dirty, it won't keep the valve open.
Yes, if a pilot light goes out, you will often smell a faint or noticeable odor. Natural gas is naturally odorless, but utility companies add a distinct chemical called mercaptan, which smells like rotten eggs or sulfur, so you can easily detect it.
A bad thermocouple primarily interrupts the gas supply, failing to signal the gas valve that a flame is present. The most common symptoms are a pilot light that will not stay lit when you release the control knob, frequent burner shutdowns, or a furnace/water heater that refuses to ignite.
A thermocouple typically lasts between 3 to 10 years. However, its lifespan heavily depends on its application, operating temperatures, and environmental conditions.
The heat exchanger is often considered the most costly part of a furnace to repair or replace. It is a critical component that transfers heat from the combustion process to the air that circulates throughout your home. Over time, heat exchangers can crack due to the constant heating and cooling cycles they undergo.
To clean a thermocouple, turn off the power and gas supply to the appliance. Let the part cool for 5 minutes. Remove it if necessary, and gently polish the metal rod with an emery cloth, fine sandpaper, or steel wool to remove carbon and soot buildup.