If adjustment is necessary you will: (1) turn off the power to the water heater, (2) remove the jacket access panel(s) and insulation exposing the thermostat(s). The thermostat protective cover(s) should not be removed. (3) Using a small screwdriver, set the thermostat(s) dial pointer(s) to the desired temperature. (4) Replace the insulation and jacket access panel(s). Turn on the power to the water heater. You can also find the information in the product manual. If you have any further questions, please give us a call, thanks!