I have a Bosch geothermal sys with 2 pipes connecting to the electric hot water heater. Our hot water has been acting strangely. The heater thermostats are set at 125 but some days the water at the tap (or shower) is 160. Then some days it is tepid. I usually hit the red reset button and that seems to get more normal water when it's not hot enough. The house is only 4 yrs old and the problem has been occurring intermittently for months now. The thermostats have been checked and were fine. Anybody else run into this?