Informational Guide

How To Clean Thermocouple On A Water Heater

by Ian Haynes

The thermocouple is a simple sensor that will connect over to a pilot light. It works to control the temperature of the furnace or water heater. As time goes on, it will start to lose its ability to register what temperature is near it, making it less efficient.  

With routine cleaning, you will be able to keep the thermocouple clean and clear, preventing further damage or malfunction. Learning how to clean a thermocouple on a water heater will help.  

There are several signs that the thermocouple is not working well. Homeowners should look for these to determine if the water heater will perform well. Some signs include: 

  • Pilot Light Goes Out
    This can happen on occasion, but if it happens all the time, the thermocouple may be to blame. 
  • Not Registering The Temperature
    A thermocouple helps to figure out what temperature it is at the time. When the water heater can’t figure out what temperature it is, then this is a sign that part is down. 
  • Water Heater Not Functioning Properly
    If the water heater can’t monitor the temperature of the water due to the thermocouple being out, the whole unit will not work. 

If you see any of these issues show up in the water heater, then you need to learn how to test a water heater thermocouple to make things easier.  

Are All Thermocouples the Same? Different Types Explained 

There are different types of thermocouples you can use for your water heater. They all vary based on the vibration, resistance, temperature range, and durability. The J, K, T, and E thermocouples are considered the base metals and are the most common that you will find.  

There are also the Nobel metal thermocouples to choose too, which are types R, S, and B. These will be used in applications that need higher temperatures. You will need to look at your water heater and decide which one will work for your needs.  

bradford thermocouple

Things You’ll Need to Clean a Thermocouple 

There are a few items that you will need to clean your thermocouple. Some of these include: 

A steel brush 

This is an optional tool that will help dust any stuck debris from the thermocouple. You can consider steel wool if there are also stains stuck on the thermocouple that you need to remove.  

Lint-free Cloth 

Choose a lint-free cloth to help with the finishing touches to clean the thermocouple. This type is the best because it is going to make sure that no fluff is left on the surface. Wipe it off to keep it soft.  

Emery cloth 

This is similar to the nail file you can use with an abrasive surface. This does have a fabric with it, but it will still work to sand down and smoothen the thermocouple so that it will perform better than before.  

Adjustable Wrench 

Keep a few types of wrenches on hand to help to adjust things and get the thermocouple clean. An adjustable wrench is the most efficient to get this done, but you can use a few different types too.  


How To Clean a Thermocouple On A Water Heater: Step By Step Guide 

The methods you use to clean the thermocouple will depend on the type of water heater you have. Some examples include: 

On Electric Water Heaters 

electric water heater

First, we will take a look at the steps you can take to clean an electric water heater thermocouple. These steps include: 

  1. 1
    Turn the power off: This is a precaution that will keep you safe from electrical shock.  
  2. 2
    Find the thermocouple: This is going to be a thin metal tubing or wire. It is close to the pilot light.
  3. 3
    Loosen the thermocouple: Once you find it, you can loosen the tool. A wrench or screwdriver will help.  
  4. 4
    Clean it: Start to scrub the thermocouple to get rid of the corrosion. Steel wool or abrasive sponges will work.  
  5. 5
    Wipe the thermocouple: Scrubbing can leave particles behind, so use a lint-free cloth to help you out.  
  6. 6
    Reattach the thermocouple: Place the thermocouple back in place. Slice it onto the metal bracket and then tighten it. You can use your hands or a wrench to get it back in place.  
  7. 7
    Turn the heater back on.  

On Gas Water Heaters 

When you want to know how to clean a thermocouple on a gas water heater, the steps will be a little different. They include: 

  1. 1
    Shut the gas inlet valve: You will need to turn off the gas to this water heater, rather than the power.  
  2. 2
    Disconnect your burner assembly: You can use a wrench to help disconnect this.  
  3. 3
    Remove the thermocouple: slice the burner assembly out so you can get to the thermocouple.  
  4. 4
    Clean it: Take the time to clean the thermocouple, wiping off any of the excess stuff that is on it. Clean the burner at the same time to remove any extra.  
  5. 5
    Reconnect it: All of the items need to go back in place. When they are there, open the gas valve again and then light it to get the water heater to work again.  

Costs of Replacing Thermocouples 

The amount you will pay to fix the thermocouple depends on how you get the work done. If you are willing to do the work yourself, it can cost $20 to purchase a thermocouple and get the job done. If you do not want to handle the work and would like to call in a plumber to help out, then it will cost an average of $150 to get done. This is more convenient, but you do pay for help from a professional.  

People Also Ask (FAQs)

How long do thermocouples last? 

When maintained properly, they can last for years and will not need to be replaced often. However, you should check them every four years to make sure that they will last a long time.  

What is the difference between thermocouple and thermopile? 

The thermocouple is just one unit that does the work itself in the water heater. The thermopile is a sequence of these thermocouples that will help create more millivolts compared to just one and is sensitive, detecting small variations in the temperature.  

Are thermocouples universal? 

There are some universal thermocouples that can work for most types of water heaters. It is best to choose the exact thermocouple for your water heater to be safe. Make sure to measure and select the right one.  

Can you bypass a thermocouple on a water heater? 

There is not a way to bypass the thermocouple on your water heater. Any method that promotes this will be unsafe and could ruin the water heater. If the thermocouple is not working, then you need to replace that part.  


The thermocouple is an integral part of your water heater, helping to monitor the heat of the water heater the whole time. Make sure that it is going to stay clean to avoid issues with the water not staying warm enough for you.  

Ian Haynes is an expert writer who has successfully deployed over 500 plumbing pages and other related content. He has an excellent understanding of home plumbing issues and translates his experiences via Plumbing Lab so readers can have a better understanding of common household problems. Outside of his work, Ian likes exploring Brooklyn with his Labrador.