Relighting a pilot light is usually a five-minute job you can do yourself
When your pilot light goes out, your furnace or water heater stops working because the thermocouple — a safety device — senses no flame and shuts off the gas. The good news is that relighting it is straightforward and requires no special tools. You'll need a long lighter or long matches, and you should have your appliance's manual nearby so you can find the exact location of the pilot light and any specific instructions for your model.
The process is the same whether you're dealing with a furnace, water heater, or gas fireplace: locate the pilot light assembly, turn the gas control knob to the "Pilot" position, hold down the ignition button while you light the pilot flame, and then switch the knob back to "On" once the flame is stable. Most pilots stay lit on the first or second try. If yours won't stay lit after three or four attempts, or if it goes out repeatedly, something else is wrong — and that's when you call a technician.
Key Takeaways
- Turn the gas control knob to "Pilot" before you attempt to light anything, so you don't flood the chamber with gas.
- Hold the ignition button down while you light the pilot with a long lighter or long match, and keep holding it for 30 seconds after the flame appears.
- Once the pilot flame is steady and blue, release the button and turn the knob to "On" to restore normal operation.
- If the pilot won't light after three attempts, or if it lights but won't stay lit, stop trying and contact a technician — a faulty thermocouple or gas valve usually needs professional replacement.
Locate the pilot light assembly on your appliance
The pilot light sits inside a small chamber at the base of your furnace, water heater, or fireplace. On most units, you'll find a metal cover or access panel you can remove by hand or with a screwdriver. Look for a small brass or steel tube with a tiny opening — that's where the pilot flame burns. Next to it you'll see the thermocouple, a thin copper rod that runs from the pilot chamber up into the control box.
Your appliance's manual will show you exactly where to look and may include a diagram. If you don't have the manual, search the model number (usually on a label inside the access panel or on the back of the unit) plus "pilot light location" online, and you'll find photos or videos for your specific model. Spend a minute getting familiar with the layout before you touch anything.
Set the gas control knob to "Pilot" and prepare to ignite
The gas control knob is usually a dial or lever on the front of the control box, labeled with positions like "Off," "Pilot," and "On." Turn it to "Pilot" — this reduces the gas flow to a safe level for lighting. You should also locate the ignition button, which is usually a small red or black button near the knob. Some older units don't have an ignition button and require you to use a match or lighter alone.
Have your long lighter or long matches ready before you proceed. A regular lighter or short matches won't reach safely into the pilot chamber, and you risk burning your hand. If you don't have a long lighter, a thin wooden stick or a rolled piece of paper lit at the stove works in a pinch — anything that gives you 6 to 8 inches of reach.
Light the pilot flame and hold the ignition button
Press and hold the ignition button with one hand. While holding it down, bring your lit lighter or match to the pilot opening and hold the flame near the small brass tube. You should see the pilot flame ignite within a few seconds — it will be small, about the size of a match head, and should burn blue or blue-white. Keep holding the ignition button down for at least 30 seconds after the flame appears. This allows the thermocouple to heat up and signal the gas valve that it's safe to stay open.
If the pilot doesn't light on the first try, release the button, wait 5 seconds, and try again. Repeat up to three times. If nothing happens after three attempts, stop — trying more than that can flood the chamber with unburned gas, which is a safety hazard. Turn the knob to "Off" and wait a few minutes before investigating further.
Release the button and switch the knob to "On"
Once the pilot flame is burning steadily and you've held the button for 30 seconds, release it. The flame should stay lit on its own — if it goes out when ready, press the button again and hold it for another 30 seconds. Once the pilot is holding steady, turn the gas control knob from "Pilot" to "On." This opens the main gas valve and allows your furnace, water heater, or fireplace to operate normally.
Listen for the sound of the main burner igniting. On a furnace or water heater, you may hear a whoosh as the main flame lights. On a fireplace, the logs or burner should ignite. If the main burner lights and stays lit, you're done — your pilot light is working again.
What to do if the pilot won't stay lit
A pilot that lights but goes out within seconds or minutes usually means the thermocouple is failing. The thermocouple is a safety device that generates a tiny electrical signal when heated by the pilot flame. If that signal is weak or absent, the gas valve closes automatically — this is a safety feature, not a malfunction. A faulty thermocouple cannot be cleaned or adjusted; it must be replaced.
Another common cause is a dirty pilot opening. If you see soot or debris around the pilot tube, you can try gently cleaning it with a thin wire or a straightened paperclip, being careful not to bend or damage the tube. But if cleaning doesn't help, or if you're uncomfortable doing it, call a technician. Replacing a thermocouple costs between $150 and $300 in most cases and requires disconnecting the gas line — this is not a DIY job.
When to call a professional instead
Stop trying to relight the pilot and call a technician if any of these explore: the pilot won't light after three attempts, the pilot lights but won't stay lit even after you hold the button for a full minute, you smell gas near the appliance, or you see water pooling around the base of a water heater. A persistent problem usually points to a thermocouple that needs replacement, a gas valve that's stuck, or a leak — all of which require professional tools and training.
If you're uncomfortable working near the gas line or the pilot chamber, or if you're unsure whether you've located the pilot light correctly, there's no shame in calling someone. A service call usually costs $100 to $200 and takes less than an hour. That's a small price for peace of mind and the certainty that the job is done safely.
Frequently Asked Questions
Can I relight the pilot if I smell gas?
No. If you smell gas, turn the gas control knob to "Off" when ready, leave the house, and call your gas company's emergency line from outside. Do not light anything, flip switches, or use your phone indoors. A gas smell usually means a leak, which is dangerous and requires professional inspection before any work is done.
How long should I hold the ignition button after the pilot lights?
Hold it for at least 30 seconds. This gives the thermocouple time to heat up and generate the signal that tells the gas valve to stay open. If you release it too soon, the pilot may go out. If it still goes out after 30 seconds, hold it for another 30 seconds on your next attempt.
What if the pilot light is yellow or orange instead of blue?
A yellow or orange flame usually means the pilot opening is dirty or the air-to-gas ratio is off. Try gently cleaning the pilot tube opening with a thin wire. If the flame stays yellow after cleaning, or if you're not comfortable cleaning it, contact a technician — a yellow flame can produce carbon monoxide and should not be left running.
Do I need to turn off the main gas valve before relighting the pilot?
No. The gas control knob on the appliance itself is all you need to turn. The main gas valve to your house should stay on. Turning the knob to "Pilot" automatically reduces the gas flow to a safe level for lighting.
How often do pilot lights go out?
A healthy pilot light should stay lit indefinitely. If yours goes out once a year or less, it's probably fine — a draft or a temporary thermocouple glitch. If it goes out more than once a year, or if it goes out repeatedly over a few weeks, the thermocouple is likely failing and should be replaced by a technician.