SERVICE PROCEDURE RG-VII
Resetting Thermal Switch
Testing and Replacement
RESETTABLE THERMAL SWITCH CONTINUITY TESTING
Step 1. Remove outer jacket door.
Step 2. Disconnect wire leads from resettable thermal switch.
Step 3. Using a multimeter capable of measuring continuity (Ohms), place one probe of meter on one of the brass connection tabs of the resettable thermal switch, and the remaining probe on the other connection tab.
Step 4. If continuity is indicated, the switch is closed, allowing millivolt current to pass.
Step 5. If continuity is not indicated, the switch is open, possibly due to an over heating condition. The switch is designed to open at predetermined temperatures depending on model. An open switch can be reset by depressing the red colored button located at the center of the switch. The overheating condition must be determined prior to putting the heater back in service.
PROBABLE CAUSE FOR RESETTABLE THERMAL SWITCH ACTIVATION
PROBABLE CAUSE |
| CORRECTIVE ACTION |
|
|
|
| 1. | Verify adequate combustion air supply is |
|
| available. |
Insufficient combustion Air | 2. | Clear jacket slot openings of any dirt, dust, |
| restrictions or other obstructions. | |
|
| |
| 3. inspect flame arrestor plate and clean with | |
|
| stiff brush and/or vacuum to remove scale |
|
| deposits and debris. |
|
| |
1. Weak switch or switch | 1. Replace resettable thermal switch | |
out of calibration. |
|
|
| 2. Verify switch color code and approximate | |
2. Incorrect switch. |
| temperature. |
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|
|
Resettable thermal switch
color code reference.
| Approximate switch |
Color Code | activation temperature |
| (open) |
|
|
Blue | 240° |
|
|
Yellow | 270° |
|
|
Red | 290° |
|
|
Flammable vapor incident
1. Replace water heater.
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