Step 1. Disconnect the thermocouple from the combination thermostat/gas valve.
Step 2. Using a multimeter capable of measuring millivolts, connect one alligator clip to the end ball or contact portion of the thermocouple and the other alligator clip to copper portion of the thermocouple.
Step 3.Following the lighting instruction label on the heater, proceed to light the pilot and allow to operate for three minutes. It will be necessary to hold the pilot button down continuously throughout this test. A reading of 20 to 30 millivolts indicates good thermocouple output.
THERMOCOUPLE REPLACEMENT (White Rodgers Mechanical)
Step 1. Turn off gas supply to the water heater. Rotate the knob of the
combination thermostat/gas valve to “OFF” position.
Step 2.Remove the outer jacket door.
Step 3. Remove the right side of inner door per Service Procedure RG-I, Steps 3a through 3c.
Step 4. Disconnect the thermocouple from the combination thermostat/gas valve. Locate other end of the thermocouple inside of the combustion chamber and remove from the pilot bracket. Pull firmly, pulling away from the pilot assembly.
Step 5. Install a new thermocouple into the pilot bracket making certain the thermocouple is fully engaged into the pilot bracket. Position the thermocouple against the left side inner door flange at its original position. Connect the other end of thermocouple to the combination thermostat/gas valve (finger tight + a 1/4 turn).
Step 6. Inspect the inner door gasket per Service Procedure RG-I, Step 4.
Step 7. Install right side inner door per Service Procedure RG-I, “Installation of Inner Door with Gasket,” Step 6 through Step 8.
Step 8.To resume operation, follow the instructions located on the lighting instruction label or the lighting
instructions located in the Installation and Operation Manual.