How to Check the Voltage on a Kenmore Water Heater's Thermocouple

Turn the temperature dial clockwise to its lowest setting. Depress the gas control knob inward with your fingers, and turn the knob clockwise to the “Off” position. This action will cut off gas flow to the pilot and allow time for any excess gas to disperse from the line.

Lift the outer door panel to the burner access with your hands to unlock the tabs from the slots on the Kenmore water heater base. Pull the outer cover away from the water heater. Depending upon your Kenmore model, lift the inner door access panel or remove the screws securing the inner access plate to the burner with a Phillips screwdriver.

Shine a flashlight into the burner compartment and locate the pilot tube and thermocouple. The thermocouple is beside the pilot tube.

Turn the nut securing the thermocouple to the bottom of the gas valve counterclockwise with a 7/16-inch open end wrench. The thermocouple is the copper tube connecting to the bottom of the gas valve on the left side. Once you loosen the nut, continue unscrewing it by hand and pull the thermocouple out of the gas valve.

Connect the red lead alligator clip of your multimeter to the copper body of the thermocouple. The best place to attach the clip is one inch below the connecting nut. Attach the black lead alligator clip to the silver top of the thermocouple. Ensure that the alligator clips are not touching any other part of the Kenmore water heater.

Place the multimeter near the burner box so you can see the scale as you attempt to light the pilot light. Adjust the scale on your multimeter to read voltage.

Push the gas valve knob inward and turn the knob to the “Pilot” position. Hold a lit wooden match over the pilot tube while depressing the gas control knob with your free hand. Once the pilot lights, continue holding down the gas control knob for one minute.

Read the voltage on your multimeter scale. The scale should show a reading of 12 or more millivolts if the thermocouple is good. A reading less than 12 millivolts or no reading is an indication of a faulty thermocouple.

Release the gas control knob and turn it back to the “Off” position. If the thermocouple is faulty, remove it and replace it with a new one. If the thermocouple is good, reinstall it into the bottom of the gas valve. When reinstalling a thermocouple into the gas valve, thread it into the gas valve until it is hand tight and turn it an additional quarter turn with the wrench.