The hot water heater is one of the most neglected appliances in a home. People often do not think about it until it starts leaking or stops producing hot water. You can save money by installing a new water heater yourself. Water heaters are available at big-box home improvement stores. Make a diagram of your water line connections so that the salespeople can get you the parts you will need for a solid installation.
Drain the Old Heater
Turn off the circuit breaker to the existing hot water heater. The circuit breaker is in the house's electrical panel box. Turn the gas valve off if you have a gas water heater. The shut-off valve will be on the gas line going to the heater. Turn off the water supply to the water heater and turn on a hot water faucet closest to the water heater. Take a garden hose and attach one end to the drain valve at the bottom of the water. Place the other end of the hose outside. Open up the water heater drain valve by turning the valve counterclockwise.
Disconnect Electrical, Gas and Water Lines
Locate the gas line union if you have a gas water tank. The union will be on the side of the tank near the gas control valve. Use a pair of pipe wrenches to disconnect the two union nuts, which will disconnect the house gas line from the water heater. On top of the gas water heater, remove the three screws that secure the vent pipe to the flue. Remove the access panel to the electrical box on top of the heater. Untwist the plastic wire nuts connecting the house wires to the water heater wiring. Remove the screw securing the clamp around the conduit and pull the conduit away from the water heater. Disconnect the two water pipes from the water heater at the unions with a pair of pipe wrenches. If your water pipes do not have unions, you will need to cut the pipes with a pipe cutter. Cut the cold water supply pipe above the shut-off valve and cut the hot water pipe in roughly the same area. The fewer joints you have in a pipe, the less chance for a leak to occur. Pull the old heater out of the house.
Install Water Heater
Set the new water heater into the room with the thermostat and drain valve facing out. Place a four-foot level along the sides of the water heater and shim the bottom with plastic shims until the water heater is level. Place the level on top of the heater to check the levelness as well. Connect the water lines from the house to the heater. The connection will depend on whether you had unions on the old system. Measure the distance from the pipe to the heater. Cut the pipe to size with a pipe cutter. Solder an adapter to one end of the pipe and slide a sleeve over the other end. Wrap plumber's tape around the connecting nipple on the tank and thread the coupling to the tank. Slide the sleeve up to the house pipe and solder the sleeve to the house pipe and water heater pipe. Measure the distance from the top of the heater to the cold water inlet pipe, taking into account the size of the new shut-off valve. Cut new copper pipe to connect the house line with the heater and solder the pipes together with the shut-off valve joining the two pipes.
Gas and Electrical Connections
Remove the electrical access plate that is on top of the water heater. Loosen the clamp that will secure the conduit to the heater. Insert the electrical wires through the clamp and secure the wires to the wires in the water heater. Connect like-colored wires together using plastic wire caps. Tighten the clamp to secure the conduit to the heater and reattach the electrical access panel. Reconnect the vent to the flue on a new gas water heater. Use three screws to secure the vent to the flue. Coat the threaded ends of the gas line with pipe dope and reconnect the gas line to the gas control valve. You will attach a straight steel pipe from the gas valve to a coupler and then attach the coupler to the house gas line.
Fill Tank and Inspect Connections
Open up the cold water valve and fill the tank with water. Leave a hot water faucet on until water starts to flow freely out of the faucet. When the water is flowing freely, the air is out of the tank and you can turn the hot water faucet off. Inspect the connections at the water supply lines and tighten if necessary. Turn the gas valve on to supply gas to the water heater. Brush a 50/50 mixture of dish soap and water over the pipe connections to check for leaks. If bubbles form around the connections, you will need to tighten the connection. Turn the circuit breaker to the water heater back on after you inspect all the connections.