I have a 50 gal. Whirlpool Energy Smart water heater about 10 years old. Was getting 5 flashing lights on control board indicating lower heating element problem. Checked resistance on both elements and was ok. Installed a new control board. Now the control board has 2 flashes indicating over limit water temperature and turning power off to the elements. Water is extremely hot. Again checked element resistance and they are both ok. Insulation at element access is in place as well as covers. There is a little moisture between the insulation and the cover at the lower element due to removing lower element during first problem when I thought the tank was empty. I have dried it as much as possible but still get the 2 flashes. Could I have a temperature sensing problem? Any other suggestions?
Basically, one if your thermostats is stuck on causing the over temp problem. Usually it's the lower one but if you can reset it and let it heat for 30 minutes or so, then see which thermostat is giving power. Or, you can just replace the lower stat.