How to Install a water heater shut off valve

Watch this video from This Old House to learn how to install an automatic shut off valve for a water heater.

Steps:

1 Turn off the water to the water heater.

2 Drain the water heater using an electric pump and garden hose.

3 Shut off the gas, then disconnect the gas line from the water heater.

4 Cut cold-water pipe leading to heater using a tubing cutter; repeat for hot-water pipe.

5 Disconnect flue from top of heater.

6 Lift heater, slide catch pan underneath, then set heater back down.

7 Reconnect gas line, after applying pipe dope to threads.

8 Screw the flue back onto heater.

9 Reconnect the hot-water pipe by soldering on a repair coupling.

10 Extend the overflow pipe with copper tubing down to catch pan.

11 Solder a copper union onto a threaded adapter; thread the adapter onto the automatic shut-off valve.

12 Solder a second threaded adapter onto the cold-water pipe.

13 Use tubing cutter to cut away enough cold-water pipe to install the shut-off valve.

14 Install shut-off valve to the cold-water pipe.

15 Plug sensor into valve; place float in water pan.

16 Turn the gas and water back on.

17 Test the valve by turning on the heater and manually raising the float valve; the heater should automatically shut off.