607.2.1 Circulation Systems and Heat Trace Systems for Maintaining Heated Water Temperature in Distribution Systems
A water distribution system having one or more recirculation pumps that pump water from a heated water supply pipe back to the heated water source through a cold water supply pipe shall be a demand recirculation water system. Pumps shall have controls that comply with both of the following:
- The control shall start the pump upon receiving a signal from the action of a user of a fixture or appliance, sensing the presence of a user of a fixture, or sensing the flow of hot or tempered water to a fixture fitting or appliance.
- The control shall limit the temperature of the water entering the cold water piping to 104°F (40°C).