A pressure switch opens or closes a corresponding switch contact as soon as a preset pressure is reached. Depending on the requirement and the design, pressure switches are used with mechanical or electronic switch contacts, with or without displays and with various setting possibilities. Pressure switches are used in a variety of industrial and technical processes.

A pressure switch is a device that operates an electrical contact when a preset fluid pressure is reached. The switch makes an electrical contact on either pressure rise or pressure fall from a certain preset pressure level. Pressure switches are in a wide range of industrial and residential applications like HVAC systems, well pumps, furnaces, etc.

A pressure switch should not be confused with a pressure transducer. A pressure transducer converts pressure into an electrical output signal.

How does a pressure switch work?

A pressure switch works either mechanically or electronically and opens or closes the switch contact depending on the measured pressure of a medium. Pressure switches are often used with pumps, valves or boosters and have the task of keeping the pressure within a predefined span, without exceeding the upper or lower limit.

How is a mechanical pressure switch constructed?

Mechanical pressure switches are inexpensive instruments based on mechanical measuring principles such as Bourdon tubes, diaphragm elements or diaphragm-piston measuring systems. The corresponding measuring element triggers the mechanical switch contact in the pressure switch. On switching, the mechanical pressure switch sends an electrical signal. The special feature of the mechanical pressure switch is that no further supply voltage is required for the electrical signal, which protects the application from failures.

How is an electrical pressure switch constructed?

An electronic pressure switch consists of a pressure sensor, a digital pressure display and an electronic switch and it performs the functions of switching, transmission and display in just one instrument. The function of the electronic pressure sensor is to convert the measured pressure into an electrical signal. When the preset pressure is reached, the electrical circuit opens or closes. In the case of an electronic pressure switch, functions such as delay time, switch point, reset point and hysteresis, among others, can be programmed, whereby the switch points and also the output signal can be adapted to the application-specific requirements. The electronic pressure switch also provides a continuous pressure display for monitoring the switching outputs and thus also serves as a digital pressure gauge.