A water heater thermocouple, a.k.a. flame sensor, plays a crucial role in regulating gas flow in gas water heaters. In older models with pilot lights, it’s usually referred to as a thermocouple. In newer units with electric ignition, it’s called the flame sensor. They serve the same purpose. For now, we’ll just use the term “thermocouple”.
A water heater thermocouple is a component of the pilot burner assembly and connects to the gas control valve situated on the exterior of the water heater. Its function is pretty basic: It converts the heat emitted by a burning flame into a small electrical current. This current acts as a switch. It enables control over the gas flow from the gas supply valve.
The thermocouple prevents the gas valve from supplying gas to the burner when it detects the absence of a flame. So, it serves as an important safety feature within your hot water system.
More often than not, a malfunctioning thermocouple is the cause behind a water heater pilot failing to ignite or the burner not remaining lit.
If it’s time to replace your water heater thermocouple, provided you have the right tools, materials, and know-how, you may attempt it yourself. Your best bet, however, is to call in a professional for the job.
Replacing Your Water Heater Thermocouple
These steps apply to replacing the water heater thermocouple on an electric ignition water heater. This should be considered a condensed version:
- In water heaters with electric ignition, the combustion chamber is located behind a sealed cover, which is secured with a gasket. To get to the combustion chamber, you need to remove the burner assembly manifold cover. This cover safeguards the chamber that houses the burner, electronic ignition, burner supply tube, pilot, and thermocouple. Detach the fasteners that secure the manifold cover plate (burner assembly). Depending on the brand and model of your water heater, the panel may be held in place by nuts, screws, or specialty tamper-resistant fasteners.
- Grasp the burner supply tube and slightly push it down to disconnect the manifold, pilot tube, and thermocouple connections. Gently take out the manifold/burner assembly from the burner combustion compartment. Be careful not to damage the internal components. If the burner doesn’t come off easily, check the base for any additional screws that may be securing it.
- If the gasket around the manifold cover plate is in good condition and you want to reuse it, carefully remove it. Otherwise remove the gasket and plan to purchase a replacement. Clean the metal surface between the cover plate and the water heater.
- Slowly and firmly twist and pull the old thermocouple from its mounting bracket. With firm pressure, it should come out easily. Be careful not to bend or deform the connection between the pilot and the thermocouple bracket. To remove the old thermocouple, pull it through the rubber grommet seal from the inside to the outside or through the opening in the manifold cover (burner assembly). If you need to, you can cut the old thermocouple to remove it.
- Insert the new thermocouple from the outside through the grommet or opening in the burner assembly manifold cover. Until it is fully seated, insert it into its mounting bracket – or until it clicks into place. So that the pilot flame surrounds the top 3/8 inches to 1/2 inch of the thermocouple tip, position the thermocouple tip.
- Place the burner back into the combustion chamber and ensure that it is properly seated. Install a new rubber manifold cover gasket or reinstall the old one if it’s still in good condition. Finally, the cover assembly can be reinstalled. Make sure you don’t over tighten the fasteners or screws.
- Now you can reconnect the gas control valve.
Rather Than All of That – Call a Professional!
When you need a water heater thermocouple replaced or some other type of a Texas water heater repair – or if you know it’s high time you replaced that beat up old water heater – there is no one better to call than Made’s Plumbing, LLC.
But why stop at water heaters? Is your toilet leaking or not working properly? We can fix it or replace it. Got a clogged drain? We can help. For any plumbing problem you need remedied, contact us before you turn to anyone else. If it’s a plumbing emergency, we’ll be there ASAP!
Call 817-962-2257 or use our convenient online form to get in touch.