Either or both elements could be bad, and/or either or both thermostats could have failed. Any of the four items, or any combination of them, can cause those symptoms.: We have a Reliance 501 water heater in our cabin that we bought 2 years ago. At time of purchase the water heater was new. It suddenly started to make very hot water, then trip the circut breaker on the tank after about 24 hours. If I reset it, it will go again for 24 hours with very hot water, then pop the breaker again. model # 5 40 20ls8f.