How To Clean Thermocouple On Water Heater

Clean Thermocouple on Water Heater

If your water heater is not heating up properly, you may have a corroded or compromised thermocouple. Keeping the thermocouple clean is a necessary step to ensuring long-lasting functionality. This guide covers how to clean a thermocouple on the hot water heater in seven easy steps.

When learning how to clean the thermocouple on your water heater, you will need to gather the necessary supplies and tools, have some basic DIY skills under your belt, and you will find it is a relatively easy and straightforward process you can accomplish yourself.

Read on for detailed instructions on how to clean the thermocouple on a water heater.

Tools Needed

Multiple tools
Source: Elena Rouame

You will need the following tools to clean a thermocouple:

  • A wrench
  • Screwdrivers
  • Emery cloth sandpaper
  • Lint-free cloth

You may also need a camera to take pictures of the assembly as you take it apart. This will make it easier to put everything back after the cleaning process.

Steps To Take When Cleaning The Thermocouple

The task of cleaning a thermocouple is pretty straightforward, and just about anyone with basic DIY skills can tackle it.

Here are all the steps involved:

Step 1: Cut off gas/power supply

The first step to cleaning a thermocouple involves cutting off the gas supply. Do this by turning off the gas valve on your gas water heater. If the system is electrical, you should turn off the power supply.

This is the standard procedure when you are cleaning the thermocouple. It also applies when you want to replace it. It is a necessary safety precaution.

Step 2: Remove the entire burner

Here is where a camera comes in handy. Your smartphone camera will do just fine. Take a picture of the burner before removing it. You will have to rely on your memory if you don’t have a camera.

Once you are ready to remove the burner, carefully disconnect it from the center. You will notice the burner is connected at three points – the main supply tube, the thermocouple, and the pilot supply tube. This may vary slightly, depending on your model. Disconnect these points to easily slide out the entire burner assembly.

Step 3: Detach the thermocouple

Now, it is time to identify the thermocouple. It is usually located next to the pilot light. Use a wrench or screwdriver to detach the dirty thermocouple.

Step 4: Observe the thermocouple

Inspect the thermocouple for dirt, debris, and corrosion. Any of these could compromise its functionality. You may need to replace the thermocouple if it is corroded. If you are dealing with debris and dirt, the next step should take care of the problem.

Step 5: Clean the thermocouple

Now use the emery cloth sandpaper to sand the ends of the thermocouple. This will remove dirt and other debris that may be on the surface. While you should gently sand the components, don’t forget to be thorough.

Step 6: Give the thermocouple a finishing touch

Use a lint-free cloth to wipe the thermocouple to give it a finishing touch. This will remove any dirt remnants and helps ensure the burner works more efficiently.

Step 7: Reassemble the burner

Go back to the picture you took and use it as a guide to replace the thermocouple into the burner and fit everything together just as it was before you took the system apart.

Reconnect the main supply tube, the thermocouple, and the pilot supply tube to the control center on the hot water heater.

Open the gas valve or main control valve or turn on the power supply, depending on the type of system you have. Once the pilot is lit, confirm that the heater is now functioning as expected.

Heater thermocouple
Source: Meaw_stocker


You may need to buy and install a new thermocouple if it is still not functioning as expected, even after cleaning it. Thankfully, you can install a new thermocouple using the same procedure as above. However, instead of cleaning a dirty thermocouple, simply install the replacement thermocouple after removing the old one from the burner assembly.

Note that cleaning a water heater thermocouple should not involve using any chemical cleaning agent. Most times, the wires are covered by soot or debris. A ball of steel wool or emery cloth sandpaper is enough to remove dirt. However, chemical dirt removing agents are likely to damage the components, leaving you with a bad thermocouple.

Frequently Asked Questions

How do I know if my thermocouple is bad on my water heater?

Your thermocouple is bad if the pilot lights, but the flame goes out when you release the button after a few seconds. In other words, the water heater pilot light won’t stay lit because the bad thermocouple cuts off the gas supply or power supply to the burner and water heater pilot.

How do you check if a thermocouple is working?

You need a multimeter to test a water heater thermocouple. You should be able to measure about 30 or 40 millivolts of voltage if your thermocouple is in good working condition. You can run the check yourself, but you may need someone to help you keep the pilot flame burning when you perform the test and determine if you need a replacement thermocouple.

What causes thermocouples to fail?

Metal fatigue can cause a thermocouple to fail. As the metal goes through regular expansion and contraction cycles due to temperature changes, it will cause the thermocouple to become weak over time.