Why does my gas fire go out after 20 minutes?

Author: Dr. Margaretta Connelly  |  Last update: Saturday, June 28, 2025

If you're having issues with your gas fireplace staying lit, it's likely one of a couple issues pertaining to either: the pilot light assembly, pilot tubing, or the thermocouple and thermopile.

Why does my gas fireplace shut off after 20 minutes?

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.

Why does my gas fire go out after 15 minutes?

Thermocouple issues, pilot light problems, blocked venting systems, safety features, and gas supply issues are common reasons why gas fireplaces shut off.

How to fix a gas fireplace that keeps going out?

Turn the gas off at the fireplace! Verify the pilot flame is out!!! You will have to clean the pilot orifice. How? You take a can of compressed air and blow out the area where the pilot flame comes out. 90% of the time this fixes the issue. (Don't be surprised if you find someting blocking the pilot.)

Why does my gas flame keep going out?

There are many possible reasons why the burner will not stay lit - the gas jet may be blocked, the valve may be set too low, the air flow may be restricted, there may be an issue with the pilot light, and so on.

Troubleshooting Gas Fireplace keeps turning off after a few minutes - Explaining mV Thermocouple

Why does my gas fire keep turning itself off?

Thermocouple and Thermopile Issues

They generate a small amount of electricity when heated by the pilot flame, signaling that the pilot light is lit and allowing the gas valve to open. Over time, these components can get dirty or fail, causing the gas fireplace to shut off abruptly or prevent it from staying lit.

Why wont the flame stay on my gas fireplace?

A gas fireplace that won't stay lit is often caused by a faulty thermocouple, an insufficient gas supply, or a blocked pilot light. Regular cleaning and inspections can often help.

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 does my gas stove shut off after a few minutes?

Why Would a Gas Stove Stop Working? There are many reasons why a gas stove would stop working, such as the gas or power going out, food debris clogging the igniter, or a broken spark module. Schedule a service professional to assess your gas stove.

Why does my gas fireplace keep going out but pilot stays lit?

This can be an indication that your fireplace thermocouple is either bad or worn out. However, if your pilot is lit but the gas fireplace isn't, then there's probably a problem with your thermopile.

How long should a gas fire be on for?

If you have either a gas fireplace insert or a direct vent fireplace, you should be able to leave your fireplace on continuously throughout the day. However, it's still very important to monitor your fireplace to make sure it is working properly.

Why is my gas leaving so fast?

There can be many reasons why your vehicle burns more fuel than usual. The issue can be as simple as your driving habits or changes in weather. Spark plug issues and dirty sensors may also negatively affect your vehicle's fuel economy.

How much to replace a thermocouple in a gas fireplace?

Fireplace thermocouple replacement costs $150 to $350 total.

Why does my gas fire pit shut off after a few minutes?

When a fire pit keeps going out, the cause is almost always the flame-sensing thermocouple. If the flame goes out immediately after you light your fire pit, this is an indication that the thermocouple isn't sensing the flame and it's turning off your gas supply.

Why does my gas oven cut out after 20 minutes?

If your oven is cutting out, even for normal heat functioning, there may well be a problem with the safety thermostat. As such, this is a great place to start – after all, replacing your thermostat is a lot cheaper than replacing your oven!

Why does my gas heater shut off after a few minutes?

If your furnace shuts off after a few minutes and starts more than eight times an hour, it may require repair. Common causes of furnace short cycling include restricted airflow, a malfunctioning flame sensor, or a poorly placed thermostat.

Why does my gas fire keep cutting out?

Poor ventilation can affect the flame as the vents become dirty or blocked, preventing sufficient airflow. It can disrupt the balance of oxygen and pressure needed for stable combustion, activate safety mechanisms, and lead to incomplete combustion and overheating, all of which can cause a gas fire to go out.

What are the signs of a bad thermocouple?

The Pilot Lights But Won't Stay Lit

If the flame lights and goes out when you release the gas control knob after holding it in for the recommended 20 to 30 seconds, that's the sign of a thermocouple malfunction.

Is it hard to replace a thermocouple on a gas fireplace?

Thermocouples are designed to detect a pilot light's loss of heat and close the gas valve to prevent a gas leak. Replacing a thermocouple is a relatively easy fix that can take less than two hours.

How do I know if my gas fireplace igniter is bad?

Gas Fireplace Igniter Isn't Sparking

If your pilot is lit and the fireplace isn't igniting when you push the button or flip the switch, the igniter may be dirty or defective.

Why does my gas fireplace go out after a few minutes?

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.

What is the most common problem with a gas fireplace?

One of the most common problems faced by homeowners with gas fireplaces is the pilot light going out or not staying lit. The pilot light is a small flame that ignites the gas burner, which produces the heat for your fireplace — if the pilot light goes out, your fireplace won't work.

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