Resettable Thermal Switch Testing And Replacement; Rg-Viii - Bradford White Defender RG130T Series Service Manual

RESETTABLE THERMAL SWITCH CONTINUITY TESTING
Step 1. Remove the outer jacket door.
Step 2. Disconnect the wire leads from the 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 overheating 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
PROBABLE CAUSE
Insufficient combustion air
Weak switch or switch out
1.
of calibration.
Incorrect switch.
2.
Flammable vapor incident
ACTIVATION
PROBABLE CAUSE
Verify adequate
1.
combustion air supply is
available.
Clear jacket slot openings
2.
of any dirt, dust,
restrictions or other
obstructions.
Inspect flame arrestor plate
3.
and clean with a stiff brush,
compressed air to remove
scale deposits and debris.
Replace resettable thermal
1.
switch.
Verify switch color code
2.
and approximate
temperature.
1. Replace water heater.
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SERVICE PROCEDURE RG-VIII
Resettable Thermal Switch
Testing and Replacement
Resettable thermal switch color
code reference
Approximate
switch
Color code activation
temperature
(open)
Blue
Yellow
Red
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