Duct High Limit Switches Control Exhaust Fans


Many buildings require a high limit switch to prevent spread of fire or smoke. If the building uses an exhaust fan to maintain cooling, many building inspectors will require a limit control to be in place, such as the TC duct high limit switch. A duct high limit switch can sense temperature change up to 200°F. If a fire or smoke is present, to avoid the exhaust fan from spreading the fire and smoke throughout the building, the duct high limit switch senses the air temperature change to shut down the exhaust fan preventing spread of the fire and smoke. Continue reading below for more information.

For more information about the TC duct high limit switch, click here to visit the product page.

Click here to purchase a Firestat high limit switch!


Duct High Limit Switches Control Exhaust FansDuct High Limit Switches Control Exhaust Fans

Many buildings have an exhaust fan installed within their duct space to maintain cool temperatures inside the building. Once the air temperature reaches a pre-determined set point, a fan switch powers on an exhaust fan to keep the building from overheating.

If a fire is present within the system, the fan will feed the flames and the building will be up in smoke quickly. By installing a duct high limit switch, this risk can be reduced. The high limit switch is installed within the exhaust system, and when higher air temperature is reached due to fire the limit switch will shut the exhaust fan down preventing the spread.

TC Duct High Limit Switch Specifications

The duct high limit switch features a helix bi-metal element that senses rapid increases in temperature. The switch is a single pole, single throw (SPST) device that opens when temperature rises between 100°F to 250°F. For more information about the TC duct high limit switch, click here to view the product details.

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