High temperature switch limit exceeded 194ºF.
- Try reset. If F00 repeats, create a demand for hot water. (DANGER: Use caution to prevent burn injury.) If water is above 194oF, test upper and lower temperature sensor with an ohmmeter. (Refer to resistance chart, this section.) Replace bad sensor. If water is below 194oF, test high temperature switch and wiring with ohmmeter. Switch should be closed at this point. If not, replace switch.
- If unit did reset successfully, let the heater run and go into the status menu to check the upper and lower temperature sensor. If either reading displayed does not make sense, check appropriate sensor with ohmmeter. (Refer to resistance chart, this section.) Replace bad sensor. Do an OHMs reading on both sensors to check continuity.
