My electric water heater all of a sudden started producing scalding hot water. Tried turning down the thermostats. No change. Replaced both thermostats. No change. Turned new thermostats way down to almost off. No change. Tested element for continuity. Tested OK. Tested for element short using continuity tester, element terminal to element flange and tank. tested both elements and both element terminals. No continuity which should indicate no short. What am I missing?
Easy fix: add an anti scalding valve right after your boiler. Remember that water under 60°C will incubate legionella that is quite dangerous so don't lower boiler's set-point temperature below that.
Also remember that (tanked) boiler work by stratification it means that quite hot water stays at top of tank while cool one lays at the bottom, so it's normal that 'first' water is hotter than set if the sensor isn't in the boiler's top.
Note: water above the sensing element is hotter than set point, water below sensing element is colder than set point.