My Furnace Pilot Light Won’t Stay Lit. What Now?

Furnace pilot light

Furnace Pilot Light Won’t Stay Lit?

Now that we are right into the middle of winter here in both the US and Canada, you’ll want to make sure that your gas furnace is ready to work and keep you and your family warm.

So if your furnace’s pilot light won’t stay on, then your natural gas furnace won’t work.

Keep reading to find out about common causes why your furnace pilot light won’t stay lit and how you can quickly remedy the situation and keep you and your family warm.

Common Causes

Some of the most common causes include problems with the pilot tube and the thermocouple.

The thermocouple works by detecting the pilot light through sensors.

A faulty thermocouple can decide on its own that the pilot light is off when you want it on and vice versa.

The problem could be as simple as the thermocouple being bent.

If this is the case, you can fix your problem by bending the thermocouple back into position.

🔥 Safety First! Turn off the Gas Valve!

Furnace Gas Supply Shutoff Valve

🛑 STOP: Before doing any work, you must shut off the Furnace’s gas supply and allow it to cool down if it has been on.

Ensure you turn off the gas at the supply valve. It’s typically marked or colored red or yellow and should be easy to find.

You can turn it off by turning it clockwise.

Gas leaks can have terrible consequences, so it’s best to avoid them altogether.

🔥 Pilot Tube

Pilot tube fitted to furnace pilot light
Pilot tube fitted to furnace pilot light

Once inside, you will have to loosen any nut that holds the pilot tube.

Pliers can work well in such narrow places. 

Gently remove both the thermocouple and the pilot tube.

Be sure not to use a wrench that’s too big for the job.

You can easily cause the tube to break or bend lines in this narrow area.

🔥 Thermocouple

While you are inspecting the thermocouple, check it for cleanliness. The issue may be that it’s just dirty.

Oxidation and mineral buildup can cause failure with the thermocouple and the pilot tube.

While you are inspecting the thermocouple, check it for cleanliness.

gas furnace pilot light assembly
Pilot Light and Thermocouple Assembly

This can easily be cleaned with fine-grain sandpaper to remove soot that has accumulated.

We prefer to use emery cloth sandpaper.

It has a fabric backing, making it very flexible and easy to sand small surfaces. 

Use consistent pressure and keep sanding until the thermocouple’s exterior is clean.

🔥 Gas Regulator

gas regulator

If you notice you have problems with the pilot lights of other gas appliances in your home, then a bad gas regulator is the likely culprit.

A gas regulator decreases the gas pressure before it makes its way through your home, feeding all of your gas appliances, such as your gas furnace. 

As your gas regulator ages, it can struggle to supply your home with enough gas flow to keep the gas flowing, resulting in a reduced gas pressure that’s not strong enough to keep your pilot light lit. 

🔥 Cleanliness is next to Godliness

A dirty pilot tube and pilot orifice can also prevent your furnace’s pilot light from staying lit.

Use the same sandpaper to clean the tip of the tube.

A small stiff wire brush can get into the nooks and crannies without damaging anything else.

A can of compressed air is good to have on hand to clean out any extra dirt or debris that may be stuck in there after cleaning with the brush.

Use a bright light under the orifice to ensure that you can see through the hole. If the hole is plugged, you must buy and fit a replacement.

🔥 Replacing the Parts

Replacing both the pilot tube, pilot light orifice, and thermocouple is in the reverse order you took it apart.

Be sure to tighten the nuts so that they don’t fall apart later.

Be careful not to force anything. It’s easy to bend or break these items in such a small area.

Once your hands are free from the area, it should be safe to turn the gas supply back on.

How to Relight your Furnaces Pilot Light

Furnace Pilot Light Won't Stay Lit? kid playing with fire
This is not how to relight a furnace…

Since there are many different furnaces out there, always follow the manufacturer’s instructions for relighting a pilot light.

If you have an older model with a standing pilot light, you can follow these necessary steps to relight the pilot light flame.

  • Check that your thermostat is in the heat mode
  • Find the pilot valve. It’s box-shaped and typically located near the gas burners. This is the gas feed for the main burners.
  • Turn the valve to the off position and wait at least a few minutes to clear away any residual gas.
  • Get ready with your source flame. Long fireplace matches work well if the pilot is hard to reach. Butane grill lighters work the best in this situation. That way, you won’t have to relight a match if you don’t get it the first time.
  • Relight your pilot light. Once the pilot flame is burning, turn the pilot valve back to the on position. This will ensure the flow of the gas and ignite your burners.

Now you should be cooking with Gas!

Don’t have a pilot light? You might have a hot surface ignitor.

Read more about it here: How to Diagnose and Repair a Bad Furnace Ignitor

Still Having Problems?

Phyxter Furnace Repair

If you still have problems, it may be with the parts themselves.

Carrying out the above steps may not rectify your issue.

If you’re a DIY’er, go ahead and replace those parts.

Since most modern furnaces have a life span of 16 to 20 years, replacing the parts should rectify the issues if your furnace is nowhere near that.

As long as there are not any other major glaring problems. 

If you’re uncomfortable replacing those parts, call your local HVAC professional to come and check out your furnace.

They have the experience to diagnose and fix your problem quickly and safely.

A qualified professional will ensure your family’s safety and get your furnace to work with optimal performance.  

When to Replace Your Furnace

Really old furnace

There are many telltale signs to give you the heads-up when you need to replace your furnace.

These can include:

  • Strange sounds
  • Higher than normal energy bills
  • Uneven heating
  • Frequently cycling on and off
  • Humidity Issues

and, of course, the frequent need to make repairs like the ones listed above.

If you are close to that 12 – 15 year mark, maybe it’s just time to replace that furnace with a newer one.

The good news is that many great models out there are much more energy-efficient than the older ones.

If you want to learn more about Home Heating, click on the image below to check out this great infographic from

Home Heating Infographic from
Home Heating Infographic from

Need Help with Furnace Replacement?

We have shared some solutions and some common problems with furnace pilot lights. 

Your furnace can be a complex system and if you’re not comfortable with DIY, then engage the expertise of a professional heating and cooling company. 

When you’re not sure who to call for furnace replacement, contact us!

We’ll connect you with qualified and experienced HVAC contractors ready to provide quotes for any service, so you can choose the contractor that fits your needs.

Contact us today to learn more about furnace repair and replacement with Phyxter!

Related Reading: Homeowners Guide to Furnace Repair: 16 Most Common Problems & Solutions

Russell Jones

Russell, a native Australian and VP of Operations at Phyxter Home Services, is also part-owner of Vernon Air Conditioning, Plumbing, and Electrical Services. When he's not busy with work projects and renovations, Russell enjoys putting his vast knowledge of home improvement to good use by sharing his tips and tricks.

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Phyxter (pronounced Fix-ter) is a national home services brand specializing in Residential HVAC, Electrical and Plumbing solutions.

Phyxter is laser-focused on writing the best articles and guides to empower homeowners to get the best out of their homes.

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