The best way to install an electric water heater includes setting it on concrete blocks to prevent minor flood damage and adding union joints to the supply lines to make the next replacement easier. Making sure the tank is full before turning on the power prevents ruining the elements.
When a water heater starts to leak, it requires replacement as it is beyond repair. Replacing the unit with one of the same size and style is usually the easiest option. In order to remove the old unit, the installer should turn off the power and drain the tank. Once it is empty, he should disconnect the electrical connection and supply lines.
The new tank should fit in the space of the old one. The installer should rotate the tank so the drain valve is accessible from the front of the unit. If they are not already in place, adding flexible supply lines makes connection of the unit easier.
After making all the connections but before turning on the power, the installer should fill the tank with water. Opening a nearby hot water faucet ensures the water entering the tank forces all the air out. Once there is a steady stream of water flowing through the faucet, he should shut off the valve and turn on the power.