SERVICE PROCEDURE AG-I
Thermocouple Testing and Replacement
For Models Using White Rodgers or
Robertshaw Gas Control
OPEN CIRCUIT THERMOCOUPLE TESTING
Step 1. Disconnect thermocouple from gas control.
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.
Figure 1
Step 3. Following the lighting instruction label on the heater, proceed to light the pilot and allow to operate for three minutes. A reading of 20 to 30 millivolts indicates good thermocouple output.
NOTE:
It will be necessary to hold the gas control knob down in the “PILOT” position continuously throughout this test.
THERMOCOUPLE REPLACEMENT
Step 1. Turn off gas supply to water heater. Rotate knob of gas control to “OFF” position.
For White Rodgers gas control, depress knob slightly and rotate clockwise to the “OFF” position.
For Robertshaw gas control, rotate knob clockwise to the “OFF” position.
| Figure 2 | Figure 3 | ||||
Step 2. | Remove outer jacket door. |
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Step 3. | Slide open inner combustion chamber door. |
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Step 4. | Disconnect thermocouple from gas control. Locate other end of |
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| thermocouple inside of combustion chamber and remove from pilot bracket. Pull firmly pulling away | |||||
| from the pilot assembly. |
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Step 5. | Install new thermocouple into pilot bracket making certain the thermocouple is fully engaged into the pilot | |||||
| bracket. Connect other end of thermocouple to gas control (finger tight + ¼ turn). | |||||
Step 6. | Route carefully through the relief opening in the combustion chamber skirt. | |||||
Step 7. | To resume operation follow the instructions located on the lighting instruction label or the lighting | |||||
| instructions located in the installation and operation manual. |
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Step 8. | Slide inner door closed when finished. |
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| Thermocouple position | |||
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Figure 4
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