I have a 40 gallon Reliance 606 electric water heater. For the past couple of days, my water heater keeps shutting off where I have no hot water. Each time, I have to take off the top panel and push the reset buttom which then it works properly. There is something that is triggering this shut down but I have no idea what. Any help on things that I need to look for to determine why this is happening would be very much appreciative.

Thanks!

Tom