When a gas fireplace starts malfunctioning, it’s important to pinpoint what’s going on and how to fix it.
One issue that can happen is when a gas fireplace is only half-lit.
If a gas fireplace is only half-lit, this means the gas burner is dirty, the thermocouple is loose, or one of the metal gas valves needs to be tightened. If nothing works, do not turn on the fireplace and consult with a specialist. It can be a safety risk if used as-is.
The main concern when a gas fireplace is only half-lit comes from it going up into the flueway.
This can create a damaging set of circumstances that could lead to a fire breaking out. Do not attempt to use the gas fireplace hoping it will get better on its own.
There is a real problem if the gas fireplace is only half-lit and it needs to be fixed.
Here is a guide on what to do if your gas fireplace is like this and what to think about during the process.
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How To Fix A Gas Fireplace That’s Only Half-Lit
1. Turn Off The Gas Valve
Turning off the gas valve is essential.
As mentioned, it is not safe to use the gas fireplace when it’s half-lit. This is dangerous as it’s possible for the flueway to get clogged and that is a serious safety hazard.
Most people don’t realize this and assume they can attempt to fix the issue without turning off the gas.
To fix this issue, you should immediately remove the front grille and turn off the gas. This can be done by accessing the gas valve.
Once the gas is off, you can then begin to pinpoint where the issue is and what you have to do about it.
2. Check The Thermocouple
To begin, you are going to want to look at the thermocouple.
The thermocouple is attached to the gas valve and can be detached using nothing more than a wrench.
Just make sure to grip it tightly and begin using the wrench to get it out. Sometimes, it can be a little tight as it has been in that position for years.
Make sure to take it out and see whether or not it’s damaged.
If it is not damaged, reconnect the thermocouple and make sure it’s as tight as it can be. This is essential as that can be the reason the gas is not flowing as it is supposed to.

3. Tighten Metal Tubes Near Gas Valve
You will also have to take a look at the metal tubes that are near the gas valve.
These tend to be made of metal and should always be tight. Unfortunately, it’s possible for these metal tubes to loosen with time and you will have to tighten them.
To do this, locate the metal tubes that are connecting to the gas valve.
You are going to look at their structural integrity including assessing whether or not they are damaged. At this point, you will tighten the metal tubes and ensure they don’t budge.
4. Consult With A Specialist (If Necessary)
This last step is only necessary if nothing seems to be working.
You cannot use the gas fireplace in its current state and that has to be kept in mind throughout the process.
If you consult with a specialist, they can take a look at where the issue is. This is essential if you are thinking about using the gas fireplace in the future.
Whether it’s deeper inside the gas fireplace or something to do with the line going into the fireplace, everything can be checked by a specialist. They will know what to look for right away.

Why Is My Gas Fireplace Not Fully Lighting?
The gas fireplace is not fully lightning because the burner is dirty, one of the connectors going to the gas valve is damaged, or the spark igniter is malfunctioning. To fix this issue, test and inspect each of these components to see where the problem lies. It’s recommended to tighten or change the components to get rid of the problem.
This is challenging but it can be fixed if you pay attention.
Do not attempt to use the gas fireplace if it is not fully lighting.
Final Thoughts
Why is my gas fireplace only half-lit?
Your gas fireplace is only half-lit because the burner is dirty, the thermocouple is loose, or one of the metal tubes going into the gas valve has come undone. To fix this issue, turn off the gas supply, tighten the thermocouple with a wrench, and tighten the metal tubes near the gas valve.
This should take care of the issue and make sure the gas fireplace is fully lit at all times.
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