Why wont my gas fire stay lit?

Author: Margot Jaskolski  |  Last update: Thursday, September 18, 2025

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.

How do you fix a gas fireplace that won't stay lit?

You need to replace the thermocouple and thermopile . Basically the thermocouple senses the flame and keeps the pilot lit and the thermopile produces the voltage to open the gas valve . If the pilot doesn't stay lit it's your thermocouple . You need to replace the thermocouple as cleaning usually doesn't work .

Why does the flame on my gas fireplace keep going out?

Other reasons your gas fireplace may keep going out include a cracked gas line, a faulty thermopile, or a blocked chimney. A cracked gas line may be caused by corrosion of the pipe material to the line. A faulty thermocouple may need to be replaced if it is not sending the correct signals to your gas valve.

Why is my gas fire not holding a flame?

The major cause of a low flame is a clogged orifice. Spiders climb in when not in use and build webs. When the gas is turned on... the web is blown across the orifice opening. Typically the burner needs to be slid off the orifice for cleaning. Use a very small drill bit or pin or bristle of steel brush.

Why wont my gas heater flame stay lit?

If the pilot light of your gas heater fails to ignite or stay lit, it may be due to a dirty pilot assembly. Over time, the pilot assembly can accumulate dust, debris, or other contaminants, which can obstruct the flow of gas or impede the proper functioning of the flame.

Fireplace Won’t Stay Lit? This Is How You Fix It!

Why does my gas flame keep going out?

Low gas pressure or a faulty gas valve can interrupt the gas supply, causing the fire to burn out. If you can smell gas near the fire, hear hissing sounds, or the gas leak detectors activate, you must contact a professional right away to check for safety.

How to clean a thermocouple on a gas heater?

How to Clean a Thermocouple
  1. Locate the pilot assembly and find the thermocouple. ...
  2. Use an adjustable wrench as needed to remove thermocouple from the gas valve.
  3. Detach the thermocouple from the pilot assembly. ...
  4. Gently scrub the thermocouple with the abrasive side of a sponge or scouring pad to remove the soot.

Why is my gas fire not staying on?

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.

How much to replace a thermocouple in a gas fireplace?

Fireplace thermocouple replacement costs $150 to $350 total.

Why wont my pilot light stay lit when I release the knob?

The flame will go out if you release the knob before it is hot. The thermocouple can become dirty and caked with grit, preventing it from heating up and detecting that the pilot is lit. As a result, the pilot will always go out after you release the reset button.

Why does my gas fire keep cutting out?

Check the gas and gas line: One of the first and simplest things to check is the gas line. If there is damage to the line, not only could it be unsafe and should be addressed immediately, but it may simply be the lack of gas to your unit that's causing the shut off. Also take this time to ensure you're not out of gas.

How do I know if my thermocouple is bad on my gas fireplace?

Common Signs of a Failing Thermocouple

Here are some common indicators: Difficulty Lighting the Fireplace: If you struggle to light your fireplace, or if it takes several tries to keep the pilot lit, it could suggest that the thermocouple is not sensing the flame correctly and is failing to keep the gas supply open.

Why won't my fire stay lit in my fireplace?

Maintain oxygen flow.

If you stack wood too tight, it can snuff out the fire because the air and oxygen doesn't flow between tightly placed wood. You must stack logs somewhat loosely to allow some oxygen flow in between: One or two inches between pieces is typically a good distance.

Why does the flame keep going out on my gas fireplace?

A stable pilot light is essential for your gas fireplace to operate correctly. If the pilot light keeps going out, it can cause the fireplace to shut off automatically. Common reasons for pilot light failure include drafts, debris in the assembly, or low gas pressure.

Why does my fire keep going out?

Insufficient ventilation can smother the flames and cause the fire to die down. This often occurs when the firewood is tightly packed or when the fire is placed in an enclosed area. Moisture in the wood: Wet or damp firewood can be a significant hindrance to keeping a fire burning.

Why won't my gas fireplace igniter stay lit?

If the pilot light on your gas fireplace won't stay lit, a very likely culprit is a component called a thermocouple. A thermocouple is a safety device and is a component of the ignition system. Its purpose is to prevent the gas valve from opening if the pilot light isn't lit.

Can I replace a thermocouple myself?

Here at Boss Plumbing, we highly recommend you not try to replace the thermocouple on your water heater yourself. Though not a highly complex water heater repair, it nevertheless does involve the use of gas. Thus, if you are unsure about what you are doing, one small mistake could lead to a disaster.

How to tell if a thermocouple is bad?

There's really just one telltale sign of letting you know when the thermocouple isn't working, and that's when the pilot light won't stay lit. If you experience this problem, it's important to have your thermocouple assessed as soon as possible.

How to keep pilot light lit on gas fireplace?

Keep your thumb on the gas.

You must keep the gas flowing to the pilot until the thermocouple is warmed up. This might take as little as 10 seconds, but I'd give it a full minute. Once you take your thumb off the valve, it should pop back out and the pilot should remain lit.

Why does my gas fireplace stay on when I turn it off?

The little flame you see in your gas fireplace after you have turned it off is called a pilot light. A Standing Pilot Light runs constantly, whether your fireplace is on or off.

Why does my gas burner ignite but wont stay on?

If a burner on your gas stove lights easily but then goes out, it may be caused by your stove vent. A vent system can affect the stability of the flame coming from the burners and cause the flame to be extinguished.

How to clean a thermocouple without removing it?

Clean the thermocouple - using the emery cloth sandpaper, sand the ends of the thermocouple and then give it a finishing touch with the lint-free cloth. Hopefully, you can get to the ends of the thermocouple without having to detach it from the assembly, but you may have to do that.

Why won't my thermocouple stay lit?

The most common reason is that something is blocking the thermocouple, which stops the gas from getting to the pilot light. You can try cleaning or replacing it, but if that doesn't work, you may need to call a professional. If your pilot keeps going out, the first thing you should do is clean the thermocouple.

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