Abstract: An external control unit to be connected between a power source and an electrically driven pump to act as a smart switch to convert a “dumb” pump into a smart pump. The control system of this invention comprises a microcontroller-operated switch, located between the power source and the pump, or other fluid flow control device to be operated by electricity, and which can be programmed to record usage data of, e.g., hot water, by the household; it sets up the operating times in accordance with such usage. A temperature sensor is connected to the microcontroller to sense a temperature change, in a hot water system is turned on, by measuring an increase in temperature to indicate flow through the hot water pipe, and to record such data. This will determine, in the context of a hot water system, when the pump should be activated to bring up hot water.

Abstract: An external control unit to be connected between a power source and an electrically driven pump to act as a smart switch to convert a “dumb” pump into a smart pump. The control system of this invention comprises a microcontroller-operated switch, located between the power source and the pump, or other fluid flow control device to be operated by electricity, and which can be programmed to record usage data of, e.g., hot water, by the household; it sets up the operating times in accordance with such usage. A temperature sensor is connected to the microcontroller to sense a temperature change, in a hot water system is turned on, by measuring an increase in temperature to indicate flow through the hot water pipe, and to record such data. This will determine, in the context of a hot water system, when the pump should be activated to bring up hot water.

Abstract: A relatively small water pump-DC motor combination, powered by batteries, provides sufficient pump power to create the flow between the hot and cold water lines necessary to maintain a substantially immediate hot water response when the hot water tap is opened. The pump is controlled by a thermal sensor signaling the pump to commence operation when the temperature in the hot water line upstream of the hot water tap is less than a predetermined value. Preferably, each of the batteries is rechargeable, most preferably utilizing a wireless system, where the power source is a distance away from the pump battery, to provide additional protection against electrical short circuits in the presence of water. Commonly available batteries of between 10 and 24 Volts can be used.