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How to Clean Thermocouple on Water Heater? Start to Finish!

Writen by Ronald Brown

Fact checked by Natalie Bridges

Table of Contents

How To Clean Thermocouple On Water

Do you all get worked up about the idea of maintaining a danger-free gas-fired water heater at home? Well, it sounds just like me.

When it comes to safety mechanisms, You can rely on the thermocouple. It plays a pivotal role in the production of potable heated water for daily activities.

If left uncleaned, the grimes and debris can impede the passage of electric current. Acquiring a good knowledge of how to clean thermocouple on water heaters will help you prevent this incident. Thus, creating perfect harmony in obtaining a potent hydronic heating system.

What Will You Need to Follow this Tutorial?


Thermocouples can rust and wear out over time. Experts presume that a 4-year cycle will make a noticeable difference in its performance compared to the first time you used it. That is why it is a must to clean it occasionally. In this tutorial, we would need the following to clean the thermocouple thoroughly :

Adjustable wrench

You would need this hardware to easily remove the burner assembly from the thermocouple connection, main burner supply tube, and pilot light tube. I prefer using a wrench with a longer handle because the longer it is, the wider it opens.

It is ideal because it fits various nut/fitting sizes that would help you efficiently disengage the lines.

I would not recommend using a plier to loosen or tighten the nuts and bolts. It is designed for gripping and cutting. Instead, you can use it to shut off the gas valve if it doesn’t include any knob or lever.

Emery Cloth Sandpaper

You can use this to sand the tip of the thermocouple to remove rust, accumulated dirt, and insects. It often contains aluminum oxide and iron abrasives that are perfect for handy metalworking. Hence, I highly recommend using this to clean the end pieces of the thermocouple.

  • Alternative – Steel Wool or abrasive sponge

If you can buy an emery cloth, kindly do so. While these two are dependable for rust removal, both can leave unwanted scratches in the thermocouple.

Lint-free cloth

This cloth takes care of the finishing touches. It is most likely the one you will use after Emery Cloth. It wipes off the remnants left by the sanding procedure. Thus, leaving the thermocouple well-polished.

A microfiber cloth is lint-free. You can preferably use it if you have it at home. Most of us use it for general cleaning purposes, and I always have it with me. I can’t think of anything else that would be of much help aside from this.

Please avoid using any cleaning solutions with this cloth as they may contain flammable chemicals. The best way to use this is to use it as is. It could pose a danger when mixed with the water heater system.

Pencil Eraser

You can also use this to clean the threads of the nut, which connects the thermocouple to the control valve. Most modern pencil erasers are made of soft vinyl material. They are usually flexible and durable, so you can rub them as hard as you want on the threads to hastily remove the soots.

Step-by-Step Instructions


Shut off the gas valve

We are talking about safety. You would not want to miss the most crucial first step, would you? Make sure that the gas valve supply is turned off. If your unit includes a power cord, please unplug it as a safety precaution. It will prevent the ignition of the pilot lights.

Pro Tip: For units without a lever/knob, use a pair of pliers to turn off the gas valve supply.

Dismantle the burner assembly

We need to dismantle the burner assembly. Using the adjustable wrench, disconnect the burner from the control module on the side of the tank. This part is connected to the thermocouple, gas tube, and pilot light tube.

After that, gently slide the entire burner out of the compartment. Detach the thermocouple, and you may now proceed with cleaning it. This step is easy and doable if you carefully check each part.

Pro Tip: If your unit includes a burner cover, unthread and loosen the mounting screws and nuts attached to the burner plate. Then, loosen the nut that binds the burner line to the control module. I also advise taking a picture while doing this step, so it will be easier for you to repeat the step next time.

Start Cleaning the Thermocouple

First and foremost, rub the tip of the thermocouple with the emery cloth sandpaper. Do it until you the corroded areas fade or disappear. Do not leave any trace of dust and debris.

Secondly, use a lint-free cloth to wipe off the remnants of the sandpaper. It retouches the thermocouple to make it look neat and functional. Lastly, proceed with cleaning the nuts. Use a pencil eraser to clean the threads of the screws.

Pro tip: Never use other cleaning solutions to avoid dealing with combustible materials. The rawer, the better. Make cleaning efficient and safe.

Clean and reassemble the burner

Since we have released the burner, it would be such a waste if we don’t clean it in the same way. How do we clean the burner? Just use the same emery cloth sandpaper used in the thermocouple earlier. Scrub the stains as much as you want until you reach your satisfactory level of cleanliness.

Finally, reassemble the burner. Use the photo you took a while ago as a guide to putting pieces back together. Just in case you forgot to capture the behind-the-scenes of your hard work, start by returning the burner assembly in the tank.

Thread and tighten the mounting screws to secure the burner plate inside. Reconnect the wires to the gas valve and hook up the thermocouple. Reattach the burner tube and the pilot tube to the gas valve. Put back the burner access cover, if applicable.

Pro tip: This is optional but if you want a proper clean-up of the burner, use a handheld vacuum cleaner with a brush to suck out the dirt out of the burner effortlessly.

Test The Water Heater Performance

Turn on the gas valve and plug in the water heater cord. Relight the pilot light and observe if it is working unerringly. Adjust the water heater to your desired temperature. I advise not to go beyond 120 degrees Fahrenheit.

Pro Tip: Some thermostats have a default temperature of 140 degrees Fahrenheit set by the manufacturer. You can tone it down and never hit the temperature dials higher than that number to avoid burns and scalds.


How was the tutorial on how to clean thermocouple on water heater? Now that you know that a dirty thermocouple could be the culprit to a faulty pilot light, I hope all of the information I shared has shed light on your wandering mind. At this moment, nothing can stop you from enjoying a relaxing hot shower on a cold Monday morning.

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