LCN 7820SEM Magnetic Door Holder

The LCN 7820SEM is part of the Sentronic® SEM 7800 series of heavy‑duty electromagnetic door holders made by LCN / Allegion. It is a floor‑mounted magnetic holder designed to hold fire or smoke barrier doors open under normal conditions, and to release (fail safe) when current is removed (for example, when a fire alarm is triggered). The magnet unit comes with die‑cast housing, a cover, armature(s), and the required screw hardware pack. It is tri‑voltage — meaning it will operate on multiple voltages (12 VDC, 24 VAC/DC, 120 VAC) — increasing its flexibility in wiring and usage. It is rated to produce about 35 pounds of holding force, sufficient for many commercial doors supplied with a compatible fire door closer. When de‑energized, the door can be manually closed by the door closer. The unit is UL listed for smoke barrier or labeled fire doors and conforms to ANSI Standard A156.15. Finishes available are typically Aluminum or Dark Bronze. The device is built for durability and reliable holding, with robust metal housing and a protective cover over the magnet.