Fenwal 35-615526-223 24V Dsi 3-Try 30Spp 7Stfi

The 35-615526-223 is a Fenwal Delay Smoke Detector (DSI) used in various HVAC systems for fire detection. It operates on 24 volts DC power and employs a three-step detection process to minimize false alarms. When smoke is first detected, the DSI initiates a 30-second pre-alarm period. If smoke persists after this initial grace period, the DSI triggers a full-fledged alarm to alert building occupants and activate fire suppression measures. Additionally, the DSI incorporates a 7-second Time-to-Fire Index (TFI) to assess the severity of the fire and guide emergency response efforts. This DSI model is commonly found in commercial and industrial HVAC systems, including those in schools, hospitals, and data centers.