Water saving system

摘要

A hot water distribution system for a dwelling or other building is designed to avoid the waste of water incident to letting the water run until hot water reaches an open hot water faucet or valve. Adjacent each hot water outlet valve there is a control unit having an inlet connected to a hot water supply line from the water heater, a supply outlet connected to the hot water faucet or valve and a return outlet connected by a return line to an inlet of the water heater. Between the inlet and the supply outlet of the control unit there is a normally closed valve which is thermostatically controlled so as to open only when water in the control unit is at or above a predetermined temperature. When a hot water faucet or valve is opened and water in the hot water supply line has cooled to a temperature below a predetermined value, the control valve remains closed and water in the hot water supply line is returned to the water heater by a circulating pump. When hot water reaches the control unit, the control valve is thermostatically opened so as to supply a full flow of hot water to the faucet or outlet valve. The water circulating pump is then turned off, thereby avoiding a waste of energy that would be incident to continuous operation of the pump.