This definately sounds like a water heating issue. after discontinuing power to the unit, remove the front panel and look for the connector with the 2 largest wires, (usually red and gray). Test for continuity between these 2 wires. If continuity is found, the problem is the control. If it reads like an open circuit, no continuity, the unit needs the heater assembly replaced. Good luck and remember safety first! Power off at the breaker can save your life! =]