What is the definition of a water differential pressure switch? A water differential pressure switch is a device used in water systems to detect changes in pressure. It works by comparing the pressure of two points in a system, one higher and one lower, and activating when the difference between them reaches a certain point. The switch is usually mounted in a pipe or tank, and can be set to respond to either a rising or falling pressure. The switch can be used to regulate water pressure, detect water leaks, or shut off a water supply when necessary. It is also commonly used to regulate pumps and motors, as well as prevent excessive pressure buildup in water systems. Water differential pressure switches are typically made of a durable material, such as stainless steel, and are designed to work in a wide range of temperatures and pressures. In order to ensure proper operation, the switch must be calibrated and maintained regularly.