Can you recirculate water in domestic hot water system loop when no water is being used for example from a sink. Closed loop.
will water move through the loop even though no water is being used at sinks or washer devices. Keep in mind the water heater is still pressurized from the cold water line.
You can recirculate water as long as drinking water is separated from waste and heating water. Regulation varies by state.
For more information:
Read "Do hot water recirculation systems work? What kind would you recommend?" a Q&A answered by Kevin Burrell.