How do I reset my A. O. Smith water heater?

To reset your A. O. Smith water heater, the procedure depends on whether you have an electric or gas model, but both have a high-temperature safety cutoff that can trip. For an A. O. Smith electric water heater, first turn off power at the circuit breaker for safety, as you will be working near 240-volt wiring. Locate the access panels on the side of the tank, there is an upper and lower panel. Remove the metal cover from the upper panel with a screwdriver, pull back the insulation, and you will see the thermostat and high limit switch. In the center there is a red reset button, also called the ECO button. If it has tripped, it will be sticking out. Press it firmly until it clicks and stays in. Replace insulation and cover and restore power. For an A. O. Smith gas water heater, there is no red button like electric models. Instead, if the water is too hot, the gas control valve may go into lockout. Turn the gas control knob to off, wait 5 minutes, then turn it back to on or pilot and relight the pilot if needed following the instructions on the label. Some gas models have a small thermal reset button near the burner door that can be pressed. If the reset button keeps tripping repeatedly, it indicates a faulty thermostat, heating element, or sediment buildup causing overheating and you should call a qualified technician.