Resettable Thermal Switch, Inspection & Replacement - Bradford White URG1PV40S*N Service Manual

UPV Series
Resettable Thermal Switch Continuity Testing
Remove outer jacket door.
Step 1.
Disconnect black wire leads from the resettable
Step 2.
thermal switch.
Using a multimeter capable of measuring
Step 3.
continuity (Ohms), place one probe of the 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 4.
allowing millivolt current to pass.
If continuity is not indicated, the switch is open,
Step 5.
possibly due to an overheating condition. The
switch is designed to open at predetermined
temperatures. 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 water
heater back into 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
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
Yellow
Red
240°
270°
290°
37
37