Bill: Once the water heater heats up the water inside, the lower thermostat does all the work (unless you drain enough hot water to cause the upper thermo to kick in). You will get a voltage reading at the terminals on the elements (110 volts) even when the thermostat is satisfied because it only breaks one leg of the 220 volts required to operate it. If the thermostat is not working you will either have no hot water…erratic performance.. or scalding water at times and a constand need to reset the ECO (the little red button located on top of the upper thermostat…..Bud.how can I tell which thermostat is not working right? Seems one is on constantly, but which one?
