My son has a RHEEM Electric Water Heater. The Pop-off valve was actuating, the ECO was tripping, and the power breaker tripped. We replaced both Thermostats. THis has solved the pop-off valve problem, however, the ECO stills trips off causing the water not to heat after a few hours (the power breaker doesn’t trip now, just the Thermostat ECO). Can you give us any ideas as to what the problem may be. WOuldn’t a bad heating element just normally open and cause a lack of heat? You assistance is greatly appreciated.
If an element burns out, it will ALMOST ALWAYS cause that element to not heat water. Once (about 25 years ago) I had an element burn out but for some reason (I,m not 100% sure why) it caused the W/H to keep heating ie: relief valve popping and snapping off on high limit. You might try replacing the elements.
One of the element wires goes directly to the ECO and the other goes through the two thermostats. If the element burns out near the themostat connection side, then the water can provide a ground path and the live side can continue heating wter using 120 volts. It will not heat very fast, but it will heat until the ECO shuts off the power to the element.