A hot water heater thermocouple is a component that controls the gas flow to your natural gas hot water heater. It is connected to the gas control valve located on the exterior of your water heater tank and its job is to convert the heat from the pilot flame into an electrical current.

When the thermocouple does not sense a flame, it stops the gas valve from delivering gas to the burner altogether. Your water heater stops delivering hot water to you home since it has no way to heat the water. Unfortunately, issues with the hot water heater’s thermocouple can be the reason why your pilot light is not igniting or the burner is not staying lit.

If you believe a bad thermocouple is the reason why your pilot light won’t stay lit, you can replace the component fairly easily with a few tools and a replacement thermocouple. Most thermocouples are universal, but if you aren’t sure, disconnect the existing thermocouple and take it to the hardware store to ensure you’re getting the right part.

If you’re up to this DIY hot water heater repair, here are our tips on how to replace a hot water heater thermocouple:

1. Turn off the gas supply. Before you begin any repairs, ensure that the gas control knob is in the “OFF” position.
2. Remover the cover from the exterior of your hot water heater. If there is a cover over the burner compartment, remove it. Unscrew the pilot tube and the thermocouple line from the burner assembly using an adjustable wrench.
3. Remove the burner assembly from inside the water heater. There may be clips holding the old thermocouple to the pilot gas supply tube which you will need to disengage.
4. Install the new thermocouple in the same way you removed the old one, inserting the probe into the fitting and the other end into the pilot gas supply.
5. Reinstall the burner assembly into the and use the wrench to reconnect the burner, pilot and thermocouple tubes.
6. Place any covers that you have removed back onto the unit.
7. Turn on the gas valve and check the lines for any leaks. Apply soapy water to any connections and watch for bubbling. If you detect a leak, shut off the gas immediately and contact a professional water heater technician for assistance.

Not comfortable replacing your thermocouple on your own? Evam Canada’s skilled hot water heater technicians are here to help repair and maintain your equipment. Contact us online today to schedule your repair appointment or give us a call at 1-905-624-5544.