Differential Pressure Switch

Introduction to Differential Pressure Switch

What is it?

Differential pressure switches are devices that monitor and control the pressure difference between two points in heating, ventilation, and air conditioning (HVAC) systems. They can be used to detect changes in airflow or filter condition, and trigger alarms or equipment shutdowns based on predetermined setpoints.

Why we use it?

We use differential pressure switches to improve system performance, optimize energy usage, and ensure safety by monitoring pressure levels in HVAC systems.

How it works?

The switch typically contains a sensing element, such as a diaphragm or bellows, which reacts to changes in pressure to open or close an electrical circuit. The device then sends a signal to the building automation system or controller, which can trigger alarms or equipment shutdowns based on the setpoints programmed.

Major brands that manufacture it

Some of the major brands that manufacture differential pressure switches include Honeywell, Johnson Controls, Schneider Electric, and Siemens.


There are different types of differential pressure switches, including electromechanical and electronic models, with various pressure ranges and setpoint adjustments to fit different applications.

How do we select it?

When selecting a differential pressure switch, consider factors such as pressure range, setpoint adjustment range, accuracy, response time, compatibility with the HVAC system, and communication protocols. Also, make sure the switch is compatible with your existing control and automation systems.

How to install it?

Differential pressure switches should be installed in the location where pressure needs to be monitored, such as a duct or pipe. They should be securely mounted using appropriate fittings or adapters, and any necessary wiring connections should be made to the building automation system or controller.

Wire connections required to receive the signals

The wire connections required to receive the signals from a differential pressure switch may vary depending on the specific device and building automation system. Typically, they will require a power supply connection and two electrical wires to connect the switch to the building automation system or controller. It's important to refer to the manufacturer's installation instructions for proper wiring connections.

in MEP
Differential Pressure Switch
Administrator December 22, 2023
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