Limit Switch

An Overview about Limit Switches

What is it?

Limit switches are devices that detect the presence or absence of an object, typically used in heating, ventilation, and air conditioning (HVAC) systems to control the movement of equipment such as dampers, valves, or fans.

Why we use it?

We use limit switches to improve system performance, optimize energy usage, and ensure safety by controlling the movement of equipment in HVAC systems.

How it works?

A limit switch typically contains a lever arm or plunger that activates a set of contacts when the object being monitored comes into contact with it. When the contacts are activated, they can trigger alarms, initiate shutdowns, or control the movement of equipment.

Major brands that manufacture it

Some of the major brands that manufacture limit switches include Honeywell, Omron, Schneider Electric, and Siemens.


There are different types of limit switches, including mechanical and proximity models, with various sensing ranges and contact configurations to fit different applications.

How do we select it?

When selecting a limit switch, consider factors such as sensing range, contact configuration, environmental conditions, and communication protocols. Also, make sure the switch is compatible with your existing control and automation systems.

How to install it?

Limit switches should be installed according to the manufacturer's recommendations. 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 signals from a limit switch may vary depending on the specific device and building automation system. Typically, they will require electrical wires that connect to the building automation system or controller. It's important to refer to the manufacturer's installation instructions for proper wiring connections.

in MEP
Limit Switch
Administrator December 22, 2023
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