HOW TO: Replace the Thermocouple on a Hot Water Heater

If there is one thing women should do more, it is their own handiwork. So many of us feel helpless in this area, but fail to realize that we can do just about ANYTHING around the house with little or no experience. The internet is a beautiful thing. If you don’t know how, Google it. Tutorials work wonders, which is why I decided to use this opportunity to snap a few photos and share some knowledge with my readers – both male and female. When something breaks, you don’t automatically have to dig down in your pockets and throw money at a professional.

This morning I woke up to a painful revelation: we had NO hot water. I went in the laundry room to see what was going on and when I checked out the hot water heater, I saw that the pilot was out. So I lit it. And I lit it again. And again. After the third try, I realized that my attempts were in vain. The pilot was lighting, but it wouldn’t STAY lit. As soon as I released the gas control valve, POOF the flame disappeared.

It was pretty obvious that I was going to have to replace the thermocouple… Off to Lowe’s I went. The universal thermocouple was ten bucks.

A call in to a technician would have been at LEAST $75, and that’s only IF they didn’t screw me over by saying it was something more serious. I don’t really trust the integrity of most people these days. Anyway, if you find yourself in my situation with a hot water heater that is seemingly busted, here is what you need to do:

CHECK THE PILOT:

Remove the door on the front of the water heater and peek in – if you don’t see a blue flame, the pilot is out. Here is how to relight it:

1. Turn the gas control valve to “OFF” and wait at least 5-10 minutes to let any gas clear. If you still smell gas at that point, leave it alone. You have a leak somewhere and you need to contact a professional.
2. Turn the temperature gauge down to “PILOT LIGHTING” if there is such a setting on your model. If not, turn it to the lowest setting available.
3. Turn the valve to “PILOT” and press down. Hold the control valve down and immediately place a lit match into the water heater to light the pilot. {If you’re unsure of where the pilot is, there should be two tubes running from the box that houses the gas control valve on the outside of the water heater into the water heater itself. At the end of those two tubes is the pilot.}
4. Continue pressing down the gas control valve for 60-90 seconds. When you release it, the pilot should remain lit. If not, try again. By the third try, if the pilot refuses to remain lit, you’ve got a problem.

The first thing you should try is pulling out the thermocouple and using some sort of abrasive paper {such as sandpaper} to clean off the carbon residue. If that doesn’t work, you’re going to have to replace the thermocouple completely. {The thermocouple is the tube running from the box that houses the gas control valve with the copper casing.}

REPLACING THE THERMOCOUPLE:

1. Turn off the gas!!! Unless you like the ever-present fear of blowing up, you’ll want to turn off the gas via the gas control valve (where you turned it off prior to trying to light the pilot) AND the gas line which connects to that box.
2. Disconnect the current thermocouple from the gas control casing on the outside of the water heater by unscrewing it from the casing {see the photo above for what that looks like – it’s the one with the copper tubing.} You should be able to loosen it with a wrench and then finish unscrewing it with your fingers.
3. Pull the thermocouple out of the pilot element inside the water heater {depending on your model, you may have to unscrew it from the bracket – mine just slid out when I pulled on it}
4. Reinstall the new thermocouple by placing it exactly as the old thermocouple was before, ensuring that the tip of the thermocouple is about 1/2″ from the pilot {the pilot is the thing at the end of the “other” tube that is in the burner assembly}.
5. Turn the main gas valve on that is on the gas line itself. Relight the pilot using the instructions above and {hopefully} your water heater will be back in commission!

Remember to turn the gas control valve from “PILOT” back to “ON” and turn up the temperature gauge to your preferred setting. :)

Here are some photos that may help you to know what you’re supposed to be looking at along the way:

The old thermocouple (see the carbon on the tip?)

The new thermocouple, ready to get popped into it’s new home :)

This is the burner assembly – the thermocouple goes in that empty slot.

The thermocouple in its new home :)

The pilot is officially LIT!

FIRE!!!! Houston, we’re gonna have HOT WATER! :)