How to clean a gas water heater thermocouple to keep your unit running well
Steven E / Friday October 4, 2024
If your gas water heater’s pilot light won’t stay lit or the burner keeps going out, don’t order a replacement yet! It might just have a dirty thermocouple. This part makes sure the pilot light is on so gas can flow to the burner. When it gets dirty, it can cause a weak connection that prevents the water heater from working correctly.
Fortunately, you can quickly and easily clean the thermocouple yourself to avoid paying for costly repairs or replacements.
If you need any replacement parts for your appliances, you can enter your model number at AppliancePartsPros.com to order them. Most orders arrive in just two business days, and we have thousands of free guides to show you how to install your new parts.
Important: The information provided in this article may not apply to your specific appliance model. While we strive to offer helpful advice for DIY appliance repairs, variations in models and configurations can lead to differences in troubleshooting steps, error codes and part replacements. For the most accurate guidance, we strongly recommend consulting the technical sheet for your specific appliance model.
What causes thermocouple problems in gas water heaters?
Over time, dust, dirt, and debris can accumulate on the thermocouple, which can affect its ability to detect the pilot light’s flame. Without a clear connection, the thermocouple might incorrectly signal that the pilot light is off, which will shut off the gas supply to the burner.
Some of the most common reasons for thermocouple issues include:
- Dirt or soot buildup
- Corrosion
- Thermocouple misalignment with the pilot flame
If your thermocouple is dirty but otherwise in good condition, a simple cleaning can often fix the problem.
How to clean the thermocouple on a water heater
Follow these steps to get your thermocouple cleaned up.
Step 1: Turn off the gas supply
Before starting any work on your water heater, you’ll need to turn off the gas supply. Switch the gas control valve to the “OFF” position, then allow the unit to cool down before proceeding.
Step 2: Access the thermocouple
Most water heater thermocouples are located near the burner assembly. You’ll need to use a screwdriver to remove the burner access panel from the water heater.
The thermocouple is a small rod located near the pilot light. You should see it connected to the gas control valve by a thin copper wire.
Step 3: Clean the thermocouple
Use fine-grit sandpaper or fine steel wool to gently rub the thermocouple’s surface and remove any soot, dirt, or corrosion. Be very careful not to bend or damage the thermocouple.
When you’re done, wipe the thermocouple down with a clean cloth so there’s no residue left.
Step 4: Reinstall the thermocouple
After cleaning the thermocouple, make sure it’s properly aligned with the pilot light. The tip of the thermocouple should be positioned close to the pilot flame but not directly in it. If it’s misaligned, gently adjust it.
Step 5: Test the unit
- Replace the burner assembly and check that all the connections are secure.
- Turn the gas valve back to the “ON” position.
- Relight the pilot light by following the manufacturer’s instructions.
- Allow the water heater to run for a few minutes. Make sure the pilot light stays lit and the burner ignites.
If your water heater still has issues after cleaning the thermocouple, it may need to be tested and/or replaced.
Why you should keep the thermocouple clean
Regularly cleaning the thermocouple helps prevent your water heater from experiencing problems related to the pilot light. Here’s how:
- A clean thermocouple can more accurately detect the pilot light so the burner can work correctly.
- Regular cleaning can help prevent corrosion and buildup that can damage the thermocouple over time.
Frequently asked questions
Get answers to some of the most common questions about thermocouples on gas water heaters.
Why does my water heater thermocouple keep getting dirty?
This happens over time after dust, soot, and other debris have accumulated on the thermocouple. It may happen more often if the burner area is exposed to dirt or the air intake is clogged.
How often should you clean the thermocouple on a water heater?
It’s recommended to clean the thermocouple at least once a year, or more often if you notice pilot light issues.
Additional information
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With nearly a decade of experience in providing top-notch customer service regarding appliance parts and repair, Steven enjoys sharing practical advice, troubleshooting tips, and interesting information to help readers stay informed.