If the new water heater is shorter and the old wires won’t reach, surface mount a in. x in. x in. metal electrical box on the wall or ceiling nearby, run the old wires to the box, and then run a new section of armored cable or electrical conduit to the water heater..Common problem with electric water heater installation is turning the power on before the tank is completely full of water. After the plumbing connections are complete, but before connecting electric power, open a water faucet all the way until the “.” water runs FULL STREAM for three minutes..How to install an electric water heater. This Home Depot guide helps you in installing an electric water heater.A water heater, especially an electric, is a very simple device. Unheated water enters one side of the tank. The water is heated by a couple of electric resistance elements that extend from the side of the tank into the middle of the water. And then on demand the water exits from the other side of the tank..
Installing the New Water Heater. Place the new water heater in a drain pan. If your water heater did not come with a new T P relief valve pre installed, simply twist in the new valve now. Install the discharge pipe from the T P relief valve toward the floor or drain. Use a flexible hose kit for water hook up..