How to Get Hot Water with a Recirculating Pump
This Old House plumbing and heating expert Richard Trethewey explains how a recirculation line can save energy, money, and time
In this video, This Old House plumbing and heating expert Richard Trethewey explains how a recirculation line can save energy, money, and time.
1. A recirculation line is a separate water pipe that runs off the hot-water line from the farthest plumbing fixture back to the water heater.
2. A pump at the water heater moves hot water through the recirculation line. Any cold water in the recirculation line is returned to the heater.
3. A check valve must be installed in the line to ensure hot water only goes in one direction.
4. An aqua-stat is mounted to the hot-water pipe. When it senses that hot water is returning to the heater, it shuts off the pump.
5. A timer is used to ensure that the system isn't maintaining the recirculation line when you're away at work or sleeping.
6. All-in-one pumps are available that have the aqua-stat and timer built into them.
7. Pumps and fittings can be used to push cold water in the hot-water pipe into the cold-water line until it senses that hot water has finally arrived from the heater.