The Alpha domestic hot water flow switch is designed for use with Alpha boilers such as the InTec, InTec2, Eco, InTec ERP, E-Tec and Evoke. As an important safety mechanism, the flow switch incorporates a sensor that sits inside the heating or hot water system pipework. The switch, which is designed to detect water flow, sends data to the boiler's printed circuit board to ensure that the burner does not fire when the system is low on water or dry.