Turn off the electric water heater, turn on the hot water faucet to drain water, turn on the pressure reducing valve and turn off the cold water valve. Then use a screwdriver to open the cover outside the sewage outlet; Unscrew the screw of the sewage outlet with a wrench, take out the magnesium rod, and clean the sewage and impurities inside. Open the cold water inlet valve and flush the inside. After no sewage is discharged, close the cold water inlet valve. Open the prepared special cleaning agent for electric water heater, inject the cleaning agent into the sewage outlet of electric water heater with the equipped syringe, and tighten the sewage outlet. Open the cold water inlet valve to inject water into the electric water heater, and close the hot water valve to soak for a certain time according to the instructions of the cleaning agent; It's time for the special cleaning agent to soak in the water heater. Open the hot water valve and twist the sewage outlet to drain. After the water is drained, turn on the cold water to fill it up, and then flush the inside until there is no foam. Replace the brand-new electric water heater magnesium rod and the sealing rubber gasket and nut of the sewage outlet, tighten it with a wrench to ensure no water leakage, and cover it; Add water again and heat. Do not use it when adding water for the first time. When it is heated to about 60 degrees, you can turn off the power and let go completely. Then add water and it can be used normally.