How to Install a Disconnect On a Water Heater

This diagram illustrates the components of a water heater

Installing a water heater disconnect (or shut-off valve) may require a basic competency with plumbing tools (like the use of a soldering rod), but it is still a project that most DIY-ers find that they are able to successfully complete. If you have never attempted the installation of a water heater disconnect before, you will be pleased to see just how simple it can be.

Things You'll Need

• Electric pump
• Garden hose
• Metal tubing cutter
• Catch pan
• Anaerobic chemical pipe thread sealant
• Wrench (optional)
• Soldering tool
• Repair coupling
• Copper tubing and copper union
• 2 Threaded adapters
• Automatic shut-off valve and sensor
• Float valve

Instructions

Install a Water Heater Disconnect

1. Shut off the water flowing to the water heater. Use the electric pump and hose to drain the water from the water heater. Turn off the gas and then disconnect the gas line from the water heater.

2. Cut the cold-water pipe that leads to the heater with your tubing cutter. Repeat with the hot-water pipe. Remove the flue from the top of the water heater. Carefully lift up the heater and slide the catch pan beneath it. Set the water heater back down on top of the catch pan.

3. Apply sealant to the threads on the gas line pipe. Reconnect the gas line. Screw the flue onto the water heater again (you may find the wrench helpful, here). Put the hot-water pipe back on by soldering onto it a repair coupling.

4. Use the copper tubing to extend the overflow pipe down to the catch pan. Take a threaded adapter and solder onto it a copper union. Thread the adapter onto the automatic shut-off valve.

5. Take your second threaded adapter and solder it to the cold-water pipe. With the tubing cutter, cut away enough of the cold-water pipe to allow the installation of the shut-off valve. Attach the shut-off valve to the cold-water pipe.

6. Plug the sensor into the valve and place the float into the water pan. Turn the water and the gas back on.

Tips & Warnings

• You can easily test the valve by turning on the water heater and then manually raising the float valve. The water heater should automatically turn off.

• Make sure that you shut off the gas and also disconnect the gas line from the water heater before you proceed to step two. Never cut any pipes on your water heater while the gas is still flowing!

Resources

• This Old House
• How your water heater works