3 Reasons Furnace Pilot Light Won’t Stay Lit After Replacing Thermocouple (Helpful Tips!)

A functional furnace often slips into the background when it comes to efficiency, safety, and overall performance.

Unfortunately, it’s normal for problems to arise with the furnace pilot light. This includes the pilot light not staying lit after replacing the thermocouple.

A furnace pilot light won’t stay lit after replacing the thermocouple because the pilot burner is unclean or the gas valve has a bad magnet. It’s recommended to clean the pilot burner using a wide bristled brush to remove debris. If the gas valve has gone, it’s best to call a specialist to replace the gas valve.

It’s essential to avoid a situation where the furnace pilot light doesn’t work because the thermocouple was replaced.

If this issue pops up, it is best to look at a solution that is straight to the point and will bring the furnace pilot light back to life as necessary.

Here is a look at why a furnace pilot light won’t stay lit and what to do about it moving forward.

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Why Furnace Pilot Light Won’t Stay Lit

1. Unclean Pilot Burner

The most common issue has to do with a malfunctioning pilot burner.

A lot of people don’t realize how much debris can accumulate within and around the pilot burner. If it is impeded in any manner, this can take away from how the pilot burner performs.

If the pilot burner is not functioning as it is supposed to, this will make it difficult for the pilot light to stay lit. Instead, the pilot light is not going to turn on and it will become difficult for it to remain useful.

In a situation such as this, you will want to clean the furnace’s pilot burner.

To clean a furnace’s pilot burner properly, it’s essential to use a wide-bristled brush. You are going to take the brush and begin to work around the pilot burner to remove the debris.

You will have to remove the pilot burner while doing this to reach into the orifice. This will ensure you remove all of the debris and it works out as you planned.

furnace pilot light won't stay lit after replacing thermocouple

2. Gas Valve Has Bad Magnet

This is a more complex issue and one that can happen from time to time.

In some cases, the furnace’s gas valve is going to start malfunctioning. When this occurs, it’s common for the gas valve to not work because the magnet won’t stay open. This means it continues to press against the gas valve keeping it locked.

The real issue is the new thermocouple is supposed to hold that magnet open when the furnace is working properly. If it doesn’t, the gas valve won’t work and it will go bad.

The goal is to either re-install the thermocouple or look at replacing the gas valve depending on where the issue is.

You should not be doing this as a DIY project.

It’s better to have a certified specialist come in and take a look at the gas valve and thermocouple. This will ensure the right connection is in place and the component doesn’t break down later on. A specialist will know what to look for and is going to help replace the component immediately.

furnace pilot light won't stay lit after replacing thermocouple

3. Incorrect Installation

This can happen if you install it on your own.

When the thermocouple is installed incorrectly, it’s possible the furnace will stop working. This can be something as simple as the connection not being stable.

You should take the time to test where the thermocouple has gone and how it is linked to the furnace. If the link is not secure, this means changes have to be made as soon as possible.

You can do it on your own again or have a specialist handle it.

This will ensure the problem goes away and the gas valve becomes to function again.

Final Thoughts

These are the reasons a furnace pilot light won’t stay lit after the thermocouple has been replaced.

A furnace pilot light won’t stay lit after the thermocouple because the pilot burner is unclean or the gas valve is not activating. This occurs because the thermocouple doesn’t hold the magnet open allowing for the gas valve to work. It’s best to clean the pilot burner using a wide-bristled brush and change the gas valve.

This will ensure the furnace pilot light works the way it is supposed to.

It’s essential to go through this information to make sure the right measures are taken moving forward. This includes how the furnace pilot light is activated.

You have to make sure the furnace pilot light stays lit.

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