How Do You Clean a Thermocouple? (The Smart and Easy Way!)

closeup of a thermocouple being cleaned

Thermocouples can sense a temperature range of -270 to 2372 degrees Fahrenheit (-170 to 1300 degrees Celsius). Such a wide range means that a dirty thermocouple can cause you to read false values on the low and high ends of the scale. So, what’s the best way to effectively clean a thermocouple? 

The simplest method to clean a thermocouple is by removing it and using a sponge soaked in a solution of 1 part distilled white vinegar and three parts water. Scrub the end of the probe with circular motions, wipe it dry with a clean towel, and insert it into the thermometer again. 

This article will go into detail on how to clean a thermocouple properly, as well as other thermocouple maintenance tips you need to know. Read on. 

What Is a Thermocouple?

Since you’ve decided to take on the task of cleaning your thermocouple, you may as well educate yourself further about this device. 

A thermocouple consists of two dissimilar metals joined at one end. When these metals come into contact with a hot surface, the resulting electrical current tells you the exact temperature. 

The most commonly used thermocouple is type K because it’s inexpensive, has a broad temperature range, and is highly resistant to corrosion

Thermocouples also act as safety devices in gas water heaters that use a pilot to ignite the burner. A thermocouple prevents the gas valve from opening if the pilot light is out, eliminating the risk of filling the area with natural gas. 

electronic thermometer with thermocouple isolated on white background

As you can imagine, dirt renders a thermocouple faulty, causing it to prevent the gas valve from opening inadvertently. Consequently, the heater might fail to heat the water in the tank. 

As such, if you’ve been having issues with your water heater, there’s a good chance that your thermocouple is compromised, with dirt being one of the main culprits. 

How To Clean a Thermocouple

If you think your thermocouple might be faulty, consider troubleshooting and cleaning before replacing it. 

Fortunately, this task is simple enough for most DIYers out there. 

You’ll need: 

  • An adjustable wrench 
  • An emery cloth 
  • Distilled white vinegar 
  • Paper towels 
  • A bowl filled with water 
  • A moistened sponge 

Once you have those items, follow these steps to clean your thermocouple:

1. Shut the Gas Inlet Valve

This step is for safety purposes. If not shut, the gas inlet valve might continue pumping natural gas into your home. Needless to say, that is one of the last things you want to happen.

While at it, you also want to turn off the pilot light or breakers of the water heater to prevent a possible fire hazard. If your heater is electric, switch it off. 

2. Remove the Thermocouple

The thermocouple is usually on top of gas water heaters and on the side for electric ones. Use an adjustable wrench to loosen and unscrew the mounting screws holding the unit in place, carefully pull it out of the heater, and set it aside. 

Depending on how well versed you are with your unit, you might need to take a picture before disassembling so you can figure out how to put it back. 

3. Clean the Thermocouple and the Burner

Take a paper towel and use it to wipe away any dirt or dust on the probe’s sheath, especially in the area where the insulation meets the sheath. 

Use an emery cloth to clean off any rust buildup on the sheath. 

Take a lint-free cloth, dip it into your water and vinegar solution, and use it to wipe away any remnants of dirt or dust on the thermocouple itself. 

Also, thoroughly clean the burner with some old rags to remove any debris. This will allow it to burn more efficiently. You can also use an old toothbrush or a brush designed for grills to get the job done. Once you’re done, let all of it dry completely before reassembling your unit.

4. Reinstall the Thermocouple

Once you’re done with cleaning the unit, put it back in place. Use your adjustable wrench to securely screw it back on top of the water heater or on top of the electric one at the side, depending on where it is. 

Reinstall the thermocouple just as it was before to ensure it works effectively. That is why taking a picture or video before removing the thermocouple is vital.

Once you have done that, turn the burner back on. Ensure that the gas inlet valve is turned back on. In turn, switch your breaker(s) or pilot light back on as well. 

5. Inspect the Thermocouple 

As a safety precaution, inspect your thermocouple for any signs of dirt or any other form of obstruction. If you notice that it’s dirty, clean it again with your paper towel, emery cloth, and vinegar solution. Also, clean the area around the thermocouple to make sure no dirt or grime can get inside.

Other Thermocouple Maintenance Tips

With proper installation and maintenance, you can rely on your thermocouple to operate effectively for years to come. 

Nevertheless, you could always put in extra effort to ensure that it operates to its full potential. 

Here are some pointers:

Install the Thermocouple Strategically

Location matters a lot. You don’t want to install the thermocouple close to the heat source, as it will give you a false impression of the tank’s actual temperature. 

Instead, find a spot further away from the heat source but still close enough to accurately gauge the temperature inside it. 

Clean the Tank

Some gas water heater manufacturers recommend that you clean your tank’s insides with a pressure washer at least once per year. 

When doing this, make sure the water’s temperature isn’t hot enough to damage your thermocouple. It should be warm instead. 

Consider spraying the interior compartment with a compressed air duster if you have an electric water heater. By doing so, you’ll be able to remove any dust or dirt from the heating elements.

Use Protective Tubes

These tubes help shield the thermocouple from external disturbances such as dust, dirt, and any other form of obstruction. 

Ensure that the protection tubes are free of: 

  • Sulfur-bearing substances 
  • Grease 
  • Oil 
  • any other form of contaminant 

Establish a Maintenance Program

For starters, consider cleaning your thermocouple every couple of months. Since it might give you a false sense of security when in use, inspect your device regularly for any signs of damages or obstructions. These obstructions can give you false readings, which can be dangerous at times.

Also, get in the habit of inspecting your unit from time to time for any: 

  • Leaks 
  • Cracks 
  • Rusts 
  • Corrosion 
  • Damages to cables and wires 
  • Missing nuts and bolts 
  • Worn-out gaskets 
  • any other form of problem 

Call the Professionals

While these tips will help maintain your thermocouple, there’s no denying that dealing with this problem is complicated and stressful. For those who have limited knowledge in electrical work, consider hiring a reputable gas/electric appliance repair expert as soon as possible. You can find a lot of them online. 

Final Thoughts

If your water tank heater isn’t performing its job effectively, there’s a good chance that you’re dealing with a faulty thermocouple. 

Fortunately, simply cleaning the thermocouple is, at times, all you need to do to fix the problem. Use the tips here to help you identify the faulty component, clean it up, and restore your water tank’s heat output. 

Remember, you can always call a professional if your unit is more complicated than that. As far as safety goes, you should never fix or maintain the unit yourself if you lack the proper expertise and equipment.

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