The thermocouple is a vital component of any hot water heater. In short, the thermocouple acts as a sensor, picking up the temperature from the pilot light to determine whether it’s on or off. This allows the water heater to regulate its temperature.
If the thermocouple on your water heater is not working properly, numerous problems can arrive. For example, your water heater might keep turning off after you’ve turned it on because it’s not able to sense the pilot light.
However, just because you notice that your water heater is shutting off, that doesn’t mean that your thermocouple is broken (Also check out Can You Still Use Water If The Water Heater Is Off?). Instead, it could just mean that you need to clean it.
In theory, this is simple enough, but it’s important to understand how to do this correctly in order to keep yourself safe and avoid damaging your thermocouple.
Here’s how to clean the thermocouple on a water heater:
How To Know When Your Thermocouple Needs Cleaning
The biggest and most obvious sign that your thermocouple is due for a clean is if your water heater keeps switching itself off after you’ve turned it on. This is a good indicator that the thermocouple is not picking up on the heat from the pilot light.
However, it’s best to clean your thermocouple before it gets to this point, because a water heater that won’t stay on for long enough to take a shower or wash dishes is a big inconvenience.
Ideally, you should regularly inspect the external and (if you feel comfortable doing so) the internal components of your water heater to check that there is no damage and that everything is working properly. When you do this, it’s also a good idea to check for dirt.
The best place to look at your thermocouple to check if it’s dirty is the tip. Usually, if the thermocouple needs cleaning, you’ll see a sooty layer on the tip, and if it hasn’t already, this will soon stop the sensor from reacting to the pilot light.
How To Clean The Thermocouple On Water Heater
Realizing that your thermocouple is dirty, you’ll probably be eager to get it clean right away to avoid any issues with your water heater.
However, you should make sure that you understand how to clean the thermocouple correctly before you get started. Otherwise, you risk hurting yourself or damaging your water heater.
Here is the best way to clean the thermocouple on your water heater:
1. Make Sure The Power Or Gas Is Off
It’s very dangerous to try and work on your water heater without shutting off the fuel supply first. Obviously, if you have an electric water heater, you must turn off the power itself, but if it’s gas-powered, the gas inlet valve needs to be shut off before you can proceed.
2. Disconnect The Burner Assembly
In your water tank, the burner assembly will be attached to the control center. It’s attached by three things, which are the pilot supply tube, the main supply tube, and the thermocouple itself. Use a wrench to disconnect any of these three things, and it should release the burner assembly.
3. Sand The Thermocouple
You will need some emery sandpaper for this. Simply use the sandpaper to sand down the thermocouple’s ends.
Once you have done this, use a lint-free cloth to finish the job. In case you can’t reach the required areas of the thermocouple, simply take it off before cleaning so that you can access both ends.
4. Scrape The Burner
You don’t necessarily need to do this, since sanding and wiping down your thermocouple should remove any dirt preventing it from picking up the heat from the pilot light. However, once you have the thermocouple or burner assembly detached, you might as well clean the burner as well.
Just scrape any dirt you find off the burner, either with the sandpaper or any other scraping tool, but be careful not to damage it in the process.
5. Reconnect The Burner
This step will be much easier if you take pictures of the components of your water heater as you detach them. That way, you’ll remember exactly where everything goes. Simply reconnect the thermocouple, main supply tube, and pilot supply tube to the control center using your pictures for guidance.
6. Turn The Fuel Supply Back On
Turn the power back on or reopen the inlet valve and turn on the pilot light. You should find that your thermocouple is working properly.
Final Thoughts
Cleaning a thermocouple on a water heater is relatively simple. You’ll need some emery sandpaper and a lint-free cloth to clean the thermocouple, and a wrench to remove the burner in the first place.
Remember to turn off the power supply or gas supply before you start working on your water heater, and turn it back on only after you have finished, to check whether everything is working properly.
Never attempt to work on a water heater that is still being supplied, and never try to conduct any complex electrical or gas work on your water heater unless you are a trained professional.
Frequently Asked Questions
Why Won’t My Thermocouple Work After Cleaning?
If you’ve cleaned your thermocouple, and it still doesn’t seem to be working with the pilot light, it could be that your thermocouple needs replacing altogether.
Alternatively, the issue with your pilot light, or your water heater turning itself off, might not be due to your thermocouple. It’s best to contact a professional for an inspection in this case.
How Do I Clean Rust Off A Thermocouple?
If your thermocouple is rusty, the method described above of sanding both ends of the thermocouple before finishing with a lint-free cloth should still be effective.
What Can I Use To Clean A Thermocouple Other Than Sandpaper?
If you don’t have any suitable sandpaper to clean your thermocouple with, you can use steel wool. Just make sure not to scrub too roughly, or you might damage the thermocouple in the process. Start by scrubbing gently, and only apply more pressure if the dirt won’t lift.
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