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5 Best Ways to Effectively Clean Thermocouple Water Heater

By Sophia W. Martin
1.9K views 2 mins read

Probably your thermocouple is dirty – that’s the first thing Jack, my tech buddy, said after I told him that the hot water temperature isn’t ‘hot’ anymore.

It acts as a safety device, but I didn’t know it could mess with the water heater’s operation. But the best thing Jack said that day was that there are tons of ways to have a clean thermocouple water heater.

Such as, the best way is to use sandpaper or emery cloth, as their cleaning is much more effective. But as an alternative, a wire brush and steel wool can work great.

But how are you going to pull this off? After all, one mistake and your thermocouple may become useless for good. Let’s make that part easier for you this time:

What Is a Thermocouple and Why Does a Water Heater Need One?

The thermocouple is a safety device that works like a double agent. It doesn’t only work as a temperature sensor but also as a safety switch at the same time.

So, when you’re seeing the pilot light on, this means it’s creating a small current. And it’s focused on keeping the gas valve open and ensuring the supply of hot water.

Here are some of the vital reasons why it is so essential:

Preventing Gas Leaks

A thermocouple will help you stop gas leaks. After all, as it shuts off the gas valve automatically, it’s quite impossible for gas to flow unnecessarily.

Lowering Energy Waste

A thermocouple makes sure the heater gets gas only when it’s needed. Plus, it shuts off the gas supply automatically at the right time. This whole process saves a lot of energy from being wasted.


As thermocouples are made out of durable materials, they can easily tolerate the high temperatures of the heater. This is what makes them keep doing their job for a long time with minimal maintenance.

Signs of a Dirty Thermocouple

The thermocouple may get dirty for a lot of reasons. So, if you’re seeing the following signs, your thermocouple probably needs a proper cleaning:

Signs of a Dirty Thermocouple
Signs of a Dirty Thermocouple

Pilot Light Issues

If your water heater’s pilot light is showing up with weird issues, it has probably gotten really dirty. Yes, I’m talking about flickering issues.

Plus, it burns inconsistently, that too can be a sign of a dirty thermocouple. Also, if your pilot light is lit but doesn’t stay that way for long, that’s also a sign of dirt in there.

Heating System Failure

A dirty thermocouple can cause your home’s water heater to fail. So, if you’re seeing the heating system shutting off frequently or not starting at all, you better be prepared to clean the thermocouple. Possibly, that’s what’s stopping the system from receiving a proper ignition signal.

Issues in Heating Performance

If you’re missing hot water due to your water heater’s inconsistent heating, it’s probably time to check how dirty it has become. The same goes for frequent cycling on and off of your furnace, as that too can be a sign of a dirty thermocouple.

Physical Dirt and Debris

Well, you don’t need to be an expert on your water heater model for this one. If you’re seeing soot, dust, or debris on your thermocouple, the ideal call is to clean it as soon as possible.

Excessive Gas Usage

Check how much gas your water heating system is consuming. It’s because if there’s a dirty thermocouple, it can lead to inefficient burning, ultimately causing higher gas consumption.

Tools and Materials Needed for the Cleaning Process

Cleaning your water heater thermocouple is a bit different than some of the regular stuff you clean. So, you’re going to need a bunch of things to pull off the job, and here’s the list:

  • Adjustable Wrench or Pliers: You need this to loosen and remove your thermocouple from the gas control valve.
  • Screwdriver: This will help you unscrew the screws that are securing the thermocouple.
  • Fine Sandpaper: You need this to remove soot, dirt, and oxidation from the tip of the thermocouple.
  • Soft Cloth: This will help you wipe off the debris and thoroughly clean the thermocouple.
  • Compressed Air: You need this to blow away loose dirt from the thermocouple.
  • Manufacturer’s Instructions: You need to follow the manufacturer’s instructions to keep the efficiency of your water heater intact.
  • Emery Cloth: This one is needed to scrub off stubborn deposits and corrosion.
  • Isopropyl Alcohol: It’s highly effective in getting rid of oil and grease from the thermocouple.
  • Replacement Thermocouple: You’re going to need this if the thermocouple is damaged or unable to function.

5 Ways to Clean Thermocouple Water Heater Safely

Indeed, a thermocouple plays an important part in the overall operation of the heater. It does great until it’s covered with dust and dirt.

Clean Thermocouple Water Heater Safely
Clean Thermocouple Water Heater Safely

So, the best thing to do is clean it up, and here are five ways you can try to have a perfectly clean thermocouple once again:

1. Emery Cloth Sandpaper Method

You can call it the most effective method to shine up your thermocouple. This will involve materials like sandpaper/emery cloth, as their abrasive nature makes them highly effective in cleaning jobs like this.

It works in the following way:

  • Shut off the gas supply to the water heater and disconnect the burner assembly.
  • Remove the thermocouple from the water heater.
  • Gently clean the tip with a fine-grit sandpaper. Make sure it’s at least 220 grit or finer. If you don’t have one, wear emery clothes.
  • Keep cleaning until the corrosion and soot are completely gone and the tip is shining again.
  • Wipe it clean with a lint-free cloth and reinstall it.

2. Steel Wool Method

This is more of an alternative to the sandpaper method. Steel wools can replicate the same kind of performance sandpaper. But that’s only when you do it the following way:

  • Turn off the gas supply to your water heater.
  • Remove the thermocouple.
  • Gently clean the tip with steel wool. Keep cleaning as long as all the deposits are completely gone.
  • Use a lint-free cloth to wipe it all down and make sure there are no remaining particles.
  • Now reattach the thermocouple to the burner assembly along with the pilot supply tube. Then turn on the gas supply.

3. Wire Brush Method

In terms of effectiveness, this one might not be as good as sandpaper. But it can still deliver a pretty good job when you’re following the needed steps in the first place:

  • Turn off the gas line and detach the thermocouple from the burner assembly.
  • Take a small wire brush and use it to clean the thermocouple. Make sure the brush is not too abrasive.
  • Keep doing it gently as long as dirt and debris are completely brushed off from the tip.
  • Wipe off the dirt with a clean cloth, and reinstall the thermocouple.

4. Cleaning Solution Method

This is a more effective method for lighter dust and debris. In fact, the best part of this one is that it doesn’t need any major experience, as you can do it like cleaning any of the regular stuff in your house.

But, as always, the ideal call is to follow these steps while doing it:

  • Prepare a mild cleaning solution first. Try using something like rubbing alcohol. Diluted vinegar solutions will also do the trick.
  • Detach the thermocouple and dampen a cloth in the solution.
  • Gently rub the thermocouple tip and clean off all the deposits.
  • Once it’s clean, dry the thermocouple thoroughly.
  • Put it back together, relight the pilot light, and ensure that your water heater is functional again.

5. Compressed Air Method

I won’t say this is a ‘champion’ method, but when you’re thinking about something to deal with lighter debris, this is your catch. Plus, this one is less hassling. So, if you want to try this one out, make sure to do it in the following way:

  • Use the blast of compressed air on the thermocouple to remove the dirt and debris.
  • If there is any stubborn dust or debris that simply doesn’t want to go with compressed air, wipe it with a clean cloth.

When Should You Call a Professional?

Clearly, you alone can’t always pull off the job, depending on the situation, of course. That’s the point when you’re going to need a professional for your thermocouple cleaning.

When Should You Call a Professional
Call a Professional

Now the question is, how will you know if you need professional help? Well, here are your clues:

Zero Experience

It’s quite normal to not have any experience handling gas appliances or water heater parts. So, when you’re unsure whether you can handle your thermocouple or not, it’s better to call a professional to handle these things.

Persistent Issues

Have you already cleaned your thermocouple? But the pilot light still goes unlit. And not to mention, the heating system also keeps malfunctioning.

If the answer to all these is yes, it’s better to let the professionals handle this, as there can be more serious issues underneath.

Physical Damage

No matter how much you clean a thermocouple, it can’t fix the physical damage. So, if you see that the thermocouple is bent, excessively corroded, or cracked, call a professional and get it replaced.

Weird Pilot Light Behavior

Don’t get surprised if your pilot light flame is acting weird (yellow or flickering), even after proper cleaning. There’s a high chance that it’s happening due to a gas pressure issue. So, it’s better to call for professional help on this part.

Gas Leaks

Always trust your nose. If you’re smelling gas during water heater thermocouple cleaning, turn off the gas valve immediately and call a professional. You’re probably going to need more than a new thermocouple this time.

Warranty Issues

When your gas water heater is under warranty, you need to be very careful about tempering it. After all, one wrong move can void the warranty. So, if you’re concerned about that, it’s better to leave things to the professionals.

Complex Systems

I won’t be surprised if you say your heating system is a bit complex. Yes, I’m talking about the ones integrated with home automation systems that come with advanced features. I don’t think any inexperienced hands should handle those.

Peace of Mind

You probably already know a lot about how to clean water heater thermocouples. Still, there’s a chance that a professional will know more and can do it in a safer way. So, if you’re into getting that peace of mind, I’d suggest calling a professional.

Wrapping Up

The life of your water heater thermocouple depends on two things – its quality and how well you’re maintaining it.

I can’t help you with the first one, but the next one is in your hands. So, in this article, all I tried was to let you know how to find out that your thermocouple has become dirty and how to clean that up in the first place.

The signs, the cleaning methods – everything’s here. Just follow the instructions as guided and you will be all good to go!

Frequently Asked Questions (FAQs)

Is there any chance of a thermocouple getting clogged?

Yes, it’s possible for a thermocouple to get clogged. This mostly happens due to dust or soot, as they prevent the thermocouple from functioning properly and lead to water heating issues.

How to know if the thermocouple has gone bad?

When the pilot light acts weird, such as having trouble staying lit or a total outage, the thermocouple has probably gone bad. Plus, the inconsistency in water temperature can also be an indicator of a faulty thermocouple.

What is the typical lifespan of a thermocouple?

The lifespan of your water heater thermocouple can be up to 10 to 15 years, but only with proper maintenance and usage. Leaving it dirty can shorten its lifespan.

How often should you clean the thermocouple?

It’s suggested to clean up the thermocouple on a water heater every six months. This will help the heater function properly and reduce the chances of it breaking down.

When should you replace or clean the thermocouple?

It will depend on how often the pilot light goes out. If the pilot light is going out every few days, it’s better to clean the thermocouple. If that doesn’t work, the ideal call is to replace the thermocouple.

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