In this video, This Old House plumbing and heating expert Richard Trethewey delivers hot water on demand.
1. Turn off the water to the house at the water main in the basement.
2. Remove off the hot- and cold-water shut-off valves underneath the bathroom sink. Cut through the valve pipes with a mini-hacksaw.
3. Install a new T-fitting to the hot- and cold-water pipes coming out of the wall.
4. Connect to each T-fitting a shut-off valve and water-supply line leading up to the faucet.
5. Now connect the T-fittings to the recirculation pump using flexible braided stainless steel hoses.
6. Secure the recirculation pump to the vanity floor with 1 ⅝-inch screws.
7. Drill a ¾-inch-diameter hole through the vanity side and install the on/off pump button.
8. Turn the water back on at the water main in the basement.
9. Plug the recirculation pump's power cord into the electrical outlet inside the vanity cabinet.
10. Press the on/off button to activate the pump. When the pump shuts off, test the hot-water faucet.