The primary difference is the electrical enclosure

Easy Calibration: Features integrated status LEDs for visual confirmation of the trip point during installation

Simply insert the sensing element or bulb into the well after applying a heat-conductive compound to ensure there are no air gaps

preventing liquid slugging and evaporator starve-out

Belimo FSNF120-S Actuator Freon The primary difference is theThe Belimo FSNF120 S is a specialized fire and smoke damper actuator designed for life safety applications in HVAC systems. Operating on 120 VAC, this spring return actuator delivers 70 in lb of torque, ensuring reliable fail safe operation during power loss or smoke detection events. Built with a rugged high strength steel housing, it meets UL555 and UL555S requirements for smoke control. This model features two integrated SPDT auxiliary switches for