How to relight pilot light on furnace? [10-Steps for gas restart]

If your struggling with relighting your gas furnace pilot light, this article is here to help!

In this guide, you will learn:

  • How to safely light the pilot light
  • The purpose of a pilot light 
  • And more!
pilot lights on furnaces

As a licensed contractor, I've had to light countless pilot lights.

A lot of gas appliances use a pilot to light the main burner. Although most newer furnaces and boilers use electronic ignition to light the burners, you may have an older model that still has a standing pilot.

Knowing how to light your pilot light can save you money on a service call, and get your heat back up and running quickly!

What You Need To Know About Igniting The Furnace Pilot

Lighting your pilot really isn't very difficult and in most cases there are instructions labeled on the furnace by the manufacturer detailing how to do it.

It's important to know the dangers when dealing with natural gas or propane. If you aren't careful you can hurt yourself or damage your equipment.

If you're uncomfortable or uncertain, call a professional. 

Supplies & Tools To Relight Furnace Pilot

  • Long matches or a grill type lighter - needed to ignite the HVAC pilot light
  • Flashlight - helps locate the pilot and gas valve button

How To Relight Furnace Pilot Light (10-Steps)

  1. Turn The Furnace Off
  2. Remove Furnace Door
  3. Set The Valve To "Pilot"
  4. Light Your Match Or Lighter
  5. Press The Button
  6. Hold For 60 Seconds
  7. Release The Button
  8. Turn The Valve To "On"
  9. Turn The Furnace Back On
  10. Put The Furnace Door On

Step 1 - Turn The Furnace Off

Always start by making sure the furnace or boiler is turned off at the thermostat. Turn power off as well.

There's usually a switch on the side of your furnace to easily shut power down. If not, turn the breaker off in your breaker panel. 

This ensures that after the pilot is lit, the main burner doesn't try to ignite while you still have your hands in the furnace.

Step 2 - Remove Furnace Door

Remove the front cover of the furnace and locate your pilot assembly.

There's a small aluminum tube coming from the gas valve going to the pilot by the burners. You should be able to follow that tube if you're having trouble locating the pilot.

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Step 3 - Set The Valve To "Pilot"

pilot lights on furnaces22

There's a knob or handle on top of the gas valve. It should be labeled, "On, Off, Pilot".

Set it to pilot so that the button can be pressed down to allow gas to flow to the pilot. You cannot press the button without the valve being set to pilot.

Step 4 - Light Your Match Or Lighter

An ignition source is needed to light the gas for the pilot light. Light your match or lighter and put it right next to the pilot.

Step 5 - Press The Button

With your flame next to the pilot, press and hold the button on the valve to allow gas to flow. It should light up almost immediately.

If it doesn't light right away, try moving the flame closer. 

If it still doesn't light, you may have a different issue and you should call a professional to check your furnace.

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Step 6 - Hold For 60 Seconds

Keep the button pressed for about a minute to allow the pilot flame to heat the thermocouple. The thermocouple is a safety device that stops the flow of gas if the pilot blows out. 

Step 7 - Release The Button

Slowly release the button on the gas valve.

Your HVAC pilot light should stay lit on its own. If it goes out, there's likely another issue and you may need to call a contractor or technician to diagnose the problem.

Step 8 - Turn The Valve To "On"

Once the pilot light is on, switch the knob or handle from "pilot" back to "on".

Your burners will not light if the valve isn't in the on position.

Step 9 - Turn The Furnace Back On

Now that the pilot is lit and the valve is back on, restore power and turn your thermostat back on.

Your furnace should now be running and heat should start blowing from your vents.

Step 10 - Put The Furnace Door On

Make sure everything is on and running and carefully put the furnace door back on.

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What Are The Causes of a Furnace Pilot Light Going Out?

Several things can cause your gas furnace pilot light to go out.

It's usually nothing major and can be corrected fairly quickly. Other times it's something more significant and a professional may need to check things to get you back up and running safely. 

Wind or Backdraft

In my experience, heavily windy days can cause pilots to blow out.

If wind blows back down your chimney, it can push the flame away from the thermocouple and the valve will close putting the pilot light out.

Your Gas Is Off

If your gas is turned off for any reason, the pilot light will no longer be lit. Simply turn the gas back on and follow the steps above to get it relit.

pilot light out on furnace (1)

You Have A Bad Thermocouple

A very common reason for your pilot to go out is a bad thermocouple.

The thermocouple is the small part in the pilot assembly that touches the flame. A copper line runs back to the gas valve to prove when a flame is present and allows the gas to flow to the pilot.

Thermocouples don't last forever and will inevitably wear out over time.

Restricted Gas Flow 

Furnaces should be cleaned regularly. The pilot assembly has a small orifice at the end of the tubing that meters the amount of gas able to flow.

If and when this orifice gets dirty, it restricts the gas pressure for the pilot light and will effect how much flame you have. You should have a steady blue flame at your pilot, not a yellow. 

If the flame is yellow, you should have your furnace cleaned to prevent the pilot light from going out.

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Frequently Asked Questions 

Can I Relight The Pilot By Myself?

Definitely yes. Relighting a pilot is usually pretty easy and if you follow these steps you should have no problems. If it won't stay lit or you're not comfortable doing so, call a professional and have them light it for you.

What Happens If A Pilot Goes Out On A Gas Furnace?

If the pilot goes out, the thermocouple will tell the gas valve to close and prevent gas from flowing.

It's a pretty common problem and generally nothing to be concerned with. It can usually be relit quickly and easily.

Is It Safe To Light A Gas Furnace Pilot Light?

Lighting a furnace pilot is a fairly safe process as long as you're careful. If you follow these steps and the relighting instructions on your equipment, you should have no issue safely lighting your pilot.

That being said, if you aren't comfortable doing this always call a professional. Your furnace can leak carbon monoxide, a dangerous and deadly gas, if repairs are not done properly.

Who Do You Call To Light A Pilot?  

If you aren't confident in lighting your gas furnace pilot light, you can call any HVAC contractor or technician to do it for you.

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Final Thoughts

If your pilot goes out, don't worry! This is a very common problem and is easily rectified.

Whether you have a gas furnace or you're restarting your pilot on a boiler, knowing how is a great skill for any homeowner to possess and can save you time and money.

Follow the steps above and you should have no problems! 

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