We came back from a 10 day vacation and found that we didn't have hot water in the shower. We have an electric hot water heater. I checked the circuit breakers and they were fine. We called a plumber and he looked at it--checked the circuits at the top and the bottom on the water heater and said everything checked out and it should be working. He (a young guy) said he would discuss it with someone else and call or come back that day. He didn't. We called again the next day and someone came out while I was gone. We then had hot water but it was VERY hot--much hotter than before--and when I went into the basement later that day I noticed that hot water was pouring out of the tube on the side--the pressure relief valve, I guess--making the basement feel a little like a sauna. We called again and someone came out and said he turned it down. According to my wife, he said that it was on 125 degrees and he turned it down to 120. After that, the water is just warm--not hot. I have turned it up slightly. I don't see "degrees" on the temperature setting but it was 2/3 of the way between "hot" and "very hot" before I changed it--closer to "very hot". Any ideas on what is going on here?

Have you tried draining the water heater lately from the base? You could have a calcium buildup and its making the water heat unevenly. It also could be dangerous. If you can't remember the last time you did it then its past the time to do it. Always a good idea to do it at least once a year and more frequent where you have a lot of minerals in your water.