The LiftMaster LMTH-135 Heat Detector is a fixed-temperature initiating device set to activate at 135°F (57°C), designed to help trigger the closing of fire-rated rolling doors and shutters when elevated heat is detected. Used as an accessory in LiftMaster commercial fire door systems, it provides a dependable means of heat-activated releasing service where code or site conditions call for thermal detection rather than smoke sensing. Typical applications include warehouses, manufacturing areas, loading docks, and other commercial or industrial spaces where fire door closure upon sustained heat is required to compartmentalize a fire.
This detector is intended for hardwired use with compatible LiftMaster fire door release devices and operator controls. Installation involves mounting the unit in the protected area and connecting it to the appropriate heat detector input on the releasing device or operator control, with placement and spacing following NFPA 72 and local codes. As a heat-activated device, it does not detect smoke and should be selected accordingly based on the life-safety design. Professional installation, regular functional testing, and periodic inspection are recommended to maintain performance and code compliance. For replacement or retrofit needs, confirm compatibility with the specific LiftMaster controller or commercial door operator before wiring.