Hello: The reset button is a high limit, which is activated by high temperature. The normal suspects, you’ve already replaced. Elements can leak current to ground, thermostats can quit functioning correctly… and these things lead to overheating. The high limit is part of the upper thermostat, so must have been replaced too. Unless you have a second defective high limit, the info doesn’t quite add up. Is the water getting very hot? The limit should trip at 180 degrees. If the water IS getting hot, you might double check the wiring with the wiring diagram to make sure nothing is in the wrong place. 😕 Hope that helps.