We have a Richmond electric water heater that is about 12 years old. About five years ago the dip tube disintegrated and was replaced. Now I have the same symptoms, the water is hot but only lasts for about five to seven minutes then cools noticeably. Also when I drained water from the bottom of the water heater it was cold. My question is, could the dip tube have gone bad again or perhaps become disconnected and given the age of this heater is it worth repairing? The last time there were dip tube debris in the system but none has been found this time.