Resettable Thermal Switch, Inspection & Replacement - Bradford White RG1D30T*(N,X) Service Manual

Res. D Series
Resettable Thermal Switch Continuity Testing
Move the gas control power switch to the
Step 1.
"OFF" position and unplug the water heater
from the wall outlet.
Remove the outer jacket door.
Step 2.
Disconnect the wire leads from the resettable
Step 3.
thermal switch.
Using a multimeter capable of measuring
Step 4.
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.
If continuity Is indicated, the switch is closed,
Step 5.
allowing millivolt current to pass.
If continuity is not indicated, the switch is
Step 6.
open, possibly due to an overheating
condition. The switch is designed to open at
predetermined temperatures depending on the
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
Insufficient combustion air
1. Weak switch or switch
is out of calibration.
2. Incorrect switch.
Flammable vapor incident
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Corrective Action
1. Verify adequate
combustion air supply is
available.
2. Clear jacket slot openings
of any dirt, dust,
restrictions or other
obstructions.
3. Inspect flame arrestor
plate and clean with a stiff
brush, compressed air
and/or vacuum to remove
scale deposits and debris.
1. Replace resettable
thermal switch.
2. Verify switch color code
and approximate
temperature.
Replace water heater.
Resettable thermal switch color code
reference
Approximate switch
Color code activation temperature
(open)
Blue 240°
Yellow
Red
270°
290°