5 Reasons the Pilot Light Won't Stay on in Your Gas Fireplace

a lit fireplace

Pilot light problems are common in gas appliances, such as water heaters, furnaces, and gas fireplaces. In most cases, the fix is something as simple and inexpensive as reigniting the pilot flame. However, if you find that your gas fireplace or similar appliance has a pilot light that won’t stay on even after consistently being fixed or relit, one of these issues could be the reason.

1. Drip Loop

It’s possible that excess moisture may have gotten into your gas line, causing the pilot light to malfunction. To verify this, look at your gas meter and find the tee that has a section of capped pipe leading down from it.

This part is called the "drip loop," and it’s designed to catch excess moisture or condensation to avoid problems just like the ones you’re experiencing. Even with that being a part of its design, it’s possible for the drip loop to overflow leaving the gas line susceptible to moisture.

If you do notice it’s overflowing, use a pipe wrench to open the cap and drain out any liquid.

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2. Thermocouple

The thermocouple is a small metal piece that crosses paths with the burning flame of the pilot light. It's a safety device that delivers gas from the gas valve to the pilot light. The thermocouple also contains wiring that goes to the gas valve and makes electricity to light the pilot.

To find out if you need a new one, turn the gas valve to pilot and then depress the override button. Hold it down for at least 30 seconds in order for the thermocouple to get warmed up.

If the pilot doesn't light, wait a couple minutes and try again. If the pilot repeatedly doesn’t light after multiple tries, then the thermocouple is probably bad.

If this is the case, remove your old thermocouple with a small wrench and take it to the hardware store with you so that you can correctly match up the length and nut size with the new one you’ll purchase. Each kit will come with varied nut adapters that can be matched up with your current size.

3. Flame Heat/Color

While the pilot light is ignited, use a flashlight to look into the pilot hole opening. Unless the flame is bright blue in color, it isn’t providing enough heat for the thermocouple to work properly.

Similarly, make sure that the pilot flame is actually reaching the thermocouple. The tiny metal rod should actually directly cross the burning flame.

Once the flame has been turned off and the metal has cooled, check to see if the thermocouple feels loose. If so, remove it and then reinstall it, using a screwdriver to remove the mounting screws.

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4. Burner

The burner is located below the pilot light and thermocouple. It is a piece with many small holes in it that allow gas to flow through toward the pilot. These tiny holes can become dirty or clogged from carbon very easily.

Try an air compressor to blow out the jets or clean the burner with soap and water. You’ll know when the gas flow is bad because you won’t get a blue flame.

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5. Gas Valve

It's very rare that the gas valve goes bad, but it can happen. If you have tried all the other solutions and nothing seems to work, then you may want to replace the gas valve. Unlike the some of the other pieces that can be checked visually and removed easily, you may need a professional plumber to help with this kind of an install since a gas valve is heavy duty stuff compared to tiny thermocouple.


Solving your pilot problems can be easy to do as long as you check each component in your gas fireplace’s gas system. However, if you don’t feel comfortable working with or around gas, then don’t. Your instincts are correct. Gas is flammable and dangerous, and it shouldn’t be handled lightly. Consult a professional contractor to do the job for you if need be.

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