Hot water circulating system

摘要

A hot water circulating system capable of increasing the amount of hot water to be circulated in each circulating cycle, decreasing energy loss and improving heat efficiency. The system includes an emptiness detecting switch which is adapted to detect start of emptying of water out of a water boiler being heated to a radiator. The switch is operatively connected directly or indirectly to an on-off valve so that the valve may be opened to flow water from an open tank to the water boiler when the switch detects start of the emptying.