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How to Replace a Gas Water Heater (page 1 of 2)

Replacing a gas water heater is a fairly basic plumbing project, but there are several dangers involved when dealing with natural gas. Use these step-by-step instructions to safely complete the project.

More in Plumbing

  • Time

    Two Days

  • Price Range

    $500 - $1,000

  • Difficulty


Here's What You Need To Do:

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.

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.

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.

tighten onto both connectors with open end wrench
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