Service Manual

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Service Procedure I
Thermostat Circuit Testing and Replacement
IMPORTANT NOTE: This procedure assumes a cool tank.
Check sensor. Sensor is held in place with a clip fastened
to the well (see image). Check sensor wire for potential
damage or breaks in the wire insulation. Is the sensor fully
inserted into the well?
Condition: Water heater not operating. Digital display
shows error code 93 (sensor reading faulty).
Unplug or disconnect electrical power to the water heater.
Check continuity of wire harness to sensor. Resistance of
harness should be close to 0 ohms. Replace wire harness
if high resistance is measured (over .5 ohms). Check
wires for intermittent connections, shorts, and/or frayed
insulation. Replace if necessary.
If wire harness is O.K., check sensor resistance detailed in
Appendix A: Sensor Resistance at Various Temperatures
(pg 29). Replace sensor if needed.
Turn power ON to water heater. Run water heater through
heating cycle and verify proper operation. Sensor
temperature can be viewed when burner shuts off (see
section on viewing the digital display in Service Mode).
Condition: Water heater not operating. Digital
display shows error code 80 high water
temperature (over 207°F).
Continued on
next page.
N
WARNING
DO NOT reset the digital display from the hard
lockout state without correcting the cause of
the overheating condition.
Turn power OFF. Draw water to cool tank below 120°F.
If sensor clip is damaged replace
clip. Replace sensor if damaged.
Check sensor resistance (see Appendix
A: Sensor Resistance, pg 29).
Y
Checking continuity
of sensor across
the two black wires
(disconnected from
control board)
The sensor is located next to the top outlet location
Sensor clip shown
properly installed
WARNING
120 volt potential exposure. Use caution
making voltage checks to avoid personal injury.
CAUTION
Use caution to NOT damage connectors when
making voltage measurements or jumping
terminals.
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