Follow the below steps to turn on AO Smith electric water heater: Ensure the electric supply to the water heater is off. Remove both upper and lower access panels and pull out the insulations.  Turn the temperature dial clockwise to increase the water temperature. Adjust the temperature according to your desired setting.  Replace both insulations and the access panels to your water heater.  Turn on the electric power to your water heater.  Wait for several hours for a tank of cold water to heat up.  Check the water temperature at several usage points like the bathtub faucet, shower, or lavatory sink.