A.O. Smith TC-049R3 Service Handbook page 52

RESIDENTIAL GAS AND ELECTRIC WATER HEATER
Residential Electric – continued
A-7 – continued
Grounded Element Test – Amperage Method – Using "clamp type" Amperage
Meter. Many multimeters could be used to conduct this test but be certain that the
thermostat is satisfied or the amperage limits of the multimeter may be exceeded.
Complaint: A grounded element is suspected whenever the water temperature
becomes excessively hot and/or the end user must push the high limit reset to
reactivate the heater.
Amperage measures the flow of current through a wire.
Watts divided by volts = Amps
Conditions
Power on
Thermostats are satisfied
Clamp the jaws of the Amp Meter around each wire connected to an element –
one wire at a time.
If ...
meter reads the proper amperage
(+5, -10%)
meter reads approximately ½ of the
proper amperage
meter reads NO amperage
Note: Amperage will only be indicated while electricity flows through a wire.
A.O. Smith Water Products Company
©2005
SERVICE HANDBOOK
... then
the thermostat is calling for heat
replace the element
thermostat and element are not grounded
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51
Technical Training Department
Ashland City, TN