E432Cold water inlet 2 (second inlet sensor) thermistor open or shorted

Field pattern: electric water heater 'fixed' by pressing reset, cold again days later (find what tripped the ECO)

The reset button is a high-limit (ECO) safety that opens when the water overheats. It does not fail by itself very often; something drove the water too hot: a thermostat stuck closed, an element shorted to the tank, or a loose, overheated wire. The wrong turn is pressing reset and leaving, or replacing only the upper thermostat without testing the elements and the wiring.