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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.
SERVICE PROCEDURE RG-VII
Resettable Thermal Switch
Testing and Replacement
20
C
ORRECTIVE 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 stiff brush
and/or vacuum to remove scale deposits and debris.
1. Replace resettable thermal switch
2. Verify switch color code and approximate temperature.
1. Replace water heater.
PR
OBABLE CA
USE FOR RESETTABLE THERMAL SWITCH A
CTIVATION
PR
OBABLE CAUSE
Insufficient
combustion Air
1. Weak switch or
switch out of
calibration.
2. Incorrect switch.
Flammable vapor
incident
Color Code
Blue
Yellow
Red
Approximate
switch
activation
temperature
(open)
240˚
270˚
290˚
Resettable thermal switch
color code reference.