Hot Water Heater Puzzle

: I have a 4 year old, 50 gallon, electric hot water : heater. A few weeks ago it began cranking out water : as hot as ever for the first 2 minutes and then over : the next few minutes it cooled rapidly until you : needed to turn off the cold entirely. You dont end : up with cold water, just a tank full of luke warm : water after 3 or 4 minutes.: I checked the continuity on both 4500 watt elements. : The needle jumped to 0 ohms. So I replaced both the : thermostats. Same problem. I assumed Id bought : faulty replacements and tried again with new : thermostats. Same problem. Yesterday I replaced : both top and bottom elements and cleaned out a small : bit of deposit on the tank bottom. Today, yep, same : problem. Im starting to wonder if I have a faulty : ciruit breaker or if its possible the cold water : fill tube is blasting cold water in near the top : of the tank or …. Im baffled and to stubborn : to admit defeat at this point.: Gary Childerssounds like the dip tube on the cold side has come apart and allowing cold water to enter at top of heater. you will have to remove fitting from cold side of heater and check this tube to see if it is in place. they have been known to fail I think a o smith heaters had a recent problem with this. good luck, keep us posted