Step 1: Remove the Old Water Heater

Before you can install a new heater, remove the old one. With a fire extinguisher close by, begin shutting off the gas valve with an adjustable open-end wrench (Image 1). Verify that no gas is leaking by first visually inspecting the pilot light, which burns off shortly, and then smelling the area (Image 2). If you do not detect a leak, turn the pilot switch to the "off" position and disconnects the exhaust duct located on top of the tank.

Note: Never use a flame to detect a gas leak.

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Step 2: Drain the Heater

Shut off the cold-water "in" valve (Image 1), and then release the water into the floor drain (Image 2). This makes the heater lighter and much easier to remove.

While waiting for the water to vacate, use a large pipe wrench to disconnect the gas line from the heater. To prevent "racking" the gas line, add a second wrench to provide some counter-torque (Image 3). Once the fitting is disconnected, double-checks that gas is not escaping.

Again, using a pair of large pipe wrenches for counter-torque, disconnect the cold "in" and hot "out" pipes in turn. This action allows more air into the heater, causing the water to drain more rapidly.

Because longer flex pipes will be used for the new connections, temporarily remove the cold-water shutoff valve. Shut off the main water located elsewhere in the residence. To remove the valve assembly, use a pipe cutter, which scores the pipe in increments until eventually breaking through. Also use the flex pipe to cut off the old hot "out" connector.

With the valve assembly removed and the water completely drained, it's out with the old and in with the new water heater.

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Step 3: Connect the New Segments of Flex Pipe

The first step to preparing the new heater installation is to connect the new segments of flex pipe. Begin by rolling Teflon tape clockwise around the cold "in" and hot "out" connectors on the heater. This creates a good seal for the flex pipe, which you will tighten onto both connectors with the open-end wrench.

Step 4: Connect a New Flexible Gas Line

You also need to connect a new flexible gas line to the pilot box. To create a tight seal, spread Teflon dope (a putty suitable for gas line connections) over the fitting. After threading the fitting into the pilot box, tighten using the open-end wrench. Remove the old fitting on the incoming gas supply with a pair of pipe wrenches. With another layer of Teflon dope, tighten a new fitting on the gas supply.

Step 5: Connect the Water Supply

To connect the water heater to the water supply you must transition the water valve removed earlier. Start by cutting off the old fittings with a pipe cutter. Then, burnish the cut ends with an emery cloth to expose fresh copper. To prepare for soldering, brush on a paste flux (Image 1) and twist on a copper union with built-in solder. Continue joining segments of pipe with unions and two new fittings in this manner. Once the correct assembly is achieved, solder using a propane torch to apply even heat to each union liquefying the solder to make a seal (Image 2).

With the new valve assembly ready to go, roll Teflon tape over the new fitting and counter-torques with open-end wrenches to connect it to the cold-water flex pipe installed earlier. Then solder a new union between the valve assembly and the incoming supply pipe (Image 3).

With the cold water supply connected, turn your attention to the hot water side. Start by soldering a new fitting to the outgoing pipe that was cut earlier (Image 4). After rolling on some Teflon tape, connect the hot flex pipe. You're now able to fill the heater with water. Turn on the main water, and then the cold-water valve. While the water is filling, connect the gas flex-line (Image 5) and reattach the duct and draft hood to vent the heater.

Once the water is completely filled, open the gas shut-off valve and ignite the pilot light, set the temperature, and the heater is ready to use.

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