These firestat duct fan and limit switches are installed in air ducts to shut down heating, air conditioning and ventilation equipment when air temperature exceeds a pre-set limit.
The Duct High Temperature Switches feature a helix bimetal element that senses rapid increases in duct temperature, such as those caused by fire. The high temperature limit then operates an SPST switch that opens with a rise in temperature. A manual reset button reactivates the temperature limit after the high-temperature condition has cleared. These duct high temperature limits are indispensable in specialized HVAC applications and Building Automation Systems. For more information about where duct fan and limit control are used, click here to visit our application notes.
The adjustable temperature duct limit switch features a helix bi-metal element that senses rapid increases in temperature.The duct limit switch operates a single pole, single throw (SPST) switch that opens when temperature rises. The adjustable duct limit switch can be set by the operator to sense 100°F to 250°F. (read more)
The TC Firestat limit switches are available as a fixed temperature option. The fixed duct limit switch offers the same benefits as our other duct limit switches, but comes preset at the required temperature. Our standard fixed temperatures include, 125°F, 165°F or 200°F. (read more)
Senasys is currently working on the R&D for other duct control possibilities. Our current product offering for the TC Series only opens on temperature rise. We are looking at other possibilities such as close on temperature rise and a DPDT switch, which will open and close two sets of contacts on temperature rise.