How to Clean a Thermocouple on Water Heater

If you think you need a new thermocouple, have you considered that maybe you need to clean the one you have? Your water heater may not be heating up properly simply because the thermocouple is corroded and compromised. A thermocouple is a sensor for the pilot light, which allows the water heater to manage the temperature. Here we cover how to clean a thermocouple on a water heater. This is a job simple enough for novice DIYers to tackle.

where the thermocouple connects to water heater

What do you need?

Adjustable wrench
Emery cloth sandpaper
Lint-free cloth

Water Heater Thermocouple Cleaning in 5 Steps

Shut the gas inlet valve - safety first! Cut the fuel supply to the water heater. This is always the first step when working on a water heater. If it's electric, cut the power. In this case, it's gas, and you need to turn off the gas valve.
Remove the burner assembly - take a picture before doing anything so you can remember how it's supposed to look when it's done. Using the wrench, you will need to disconnect the burner assembly from the control center. It's connected in three places (thermocouple, main supply tube, and pilot supply tube). Once those are disconnected, you should be able to slide the entire assembly out from its compartment.
Clean the thermocouple - using the emery cloth sandpaper, sand the ends of the thermocouple and then give it a finishing touch with the lint-free cloth. Hopefully, you can get to the ends of the thermocouple without having to detach it from the assembly, but you may have to do that. If you do, take care that you put it back together exactly how it was. Take a picture!

(Optional) Clean burner - while you have it out, now is an excellent opportunity to scrape any debris off the top of the burner. It will burn more efficiently if you remove encumbrances.
Replace and reconnect the burner assembly - remember that picture you took? You want everything to look the same when you're done here. Reconnect the three lines to the control center on your water heater tank.
Light the pilot - you need to open the gas valve, light the pilot, and turn the dial to your desired temperature (we recommend no hotter than 120-degrees F). Once that's all done, you should be back in business.

Now What?

Give your water heater time to warm up. If it's working, then great! If it's still not working, you may need to cough up the dough and buy a new thermocouple. You're in luck because PlumbersStock has a great selection of water heater parts. When you get your new one, you can read our article about replacing a water heater thermocouple. You can learn more about thermocouples in general here: Thermocouples | Wikipedia

Please feel free to contact us about any product questions or questions relating to your home improvement projects.