Either the lower element is the problem and you changed the upper one needlessly, or you have the non-adjustable upper thermostat and that needs to be replaced with an adjustable version.: : My Reliance manufactured water heater has the same type problems the others stated. The heater is 11 years old, 40 gal., has two elements – 4500 watts each. I have the temperature set at about 110-115. The breaker on the upper thermostat would kick, Id reset it, water would get very hot, work for a few days, then kick…etc. I replaced the upper thremostat, everything was fine for about four months. Now it kicks every other dayor more often. What causes this? How do I trouble shoot the problem? What are the best options for correcting this with a long term solution? Thanks.