Technical Blog

Types of Pressure Switch

Pressure switches part of our range of pressure sensors. There are different types available making them suited to different applications.

We have been supplying pressure switches for many years, our range come from our trusted suppliers and partners as well as our own range; the EPS01, EPS02, EPS03 and VPS100A can be seen on our website.

Working Principle of a Pressure Switch

Pressure switches are electrical devices used to measure pressure in an environment in comparison to a set limit. The limit will differ depending on the type of pressure switch and the application they are being used for.

Pressure switches have an internal diaphragm, and a port (or ports). Pressure enters the switch through the port and will hit the diaphragm causing some deformation. Depending on the set limit, the deformation will cause the switch contacts to make or break the circuit which triggers the switch either on or off depending on if it has been wired normally open or normally closed.

Types of Pressure Switch

Static/Gauge Pressure Switches – static or gauge pressure switches are the most common type of pressure switch. They have one port where the pressure enters and reaches the sensing diaphragm. The pressure switch is set to a limit, when the system pressure changes to exceed/ fail the limit the pressure switch will trigger the alarm.

This is the simpler pressure switch type as only one pressure variable is being monitored. Many of our options have a field adjustable set point with standard pressure ports and mounting options.

Differential Pressure Switches – differential pressure switches have two ports for pressure to enter. The pressure between the two is compared, if one of them changes the switch is triggered.

A common application for this type of pressure switch is checking for blockages in extractor fans. Each port is connected to the system to monitor the air pressure on either side of the fan. If the fan is blocked the pressure on one side will drop which will trigger the switch.

Applications of Pressure Switches

Pressure switches are a common device and have many uses. They are widely used across many industries for various applications.  

Some applications examples for pressure switches include;

  • Filtration systems
  • Detecting blockages in various systems
  • Compression units in medical facilities
  • Solution levels on DNA testing machines
  • Monitoring oxygen levels in gas tanks
  • Medical breathing apparatus including ventilators
  • Liquid dispensing in drinks machines
  • Water levels in white goods; washing machines etc
  • HVAC boiler room controls
  • Crop spraying machinery for agriculture


Pressure Switches from Variohm 

We have a wide range of pressure switches available to view on our website, our range is a combination of products from our trusted suppliers as well as some of our own products.

Browse our full range here. 

Find out more about static pressure switches and differential pressure switches by reading the following posts;

For further information on our pressure switches or any of the products in our portfolio, contact us.

Article published on: 15/07/2021