I just replaced my hot electric hot water heater. And since I replaced it, I can only get about ten minutes of hot water and then it goes cold. I checked for power to my top element I had 240 volts. I checked the resistance of the upper element and it was only four ohms. The bottom element is 18 ohms. I then unhooked the power and ground wires from the hi limit controls and the resistance of the upper element went to 18 ohms as well. Is this normal?

I just replaced my hot electric hot water heater. And since I replaced it, I can only get about ten mins of hot water and then it goes cold. I checked for power to my top element I had 240 volts. I checked the resistance of the upper element and it was only four ohms. The bottom element is 18 ohms. I then unhooked the power and ground wires from the hi limit controls and the resistance of the upper element went to 18 ohms as well. Is this normal?Oh. I just wanted to add one thing. I only have a black and a red wire going to this hot water heater.

Any chance you reversed the hot and cold water piping when installing? In order to check the resistance, you probably need to dis-connect both wires. Any chance you turned on the power before you completely filled the tank? One thing to remember is that only one element works at a time. Using ohms law, you can determine the proper resistance of the element by determining the wattage, should be marked on the element.