Lcn sem7850-al Sentronic Magnetic Door Holder

Product Description

The LCN sem7850-al is a Sentronic series electromagnetic door holder designed to hold open fire-rated and standard doors in commercial and institutional buildings. The unit mounts to the wall or floor and uses a low-voltage electromagnetic coil to maintain a hold-open force on the door armature. When power is interrupted — whether by a fire alarm system, smoke detector, or manual override — the magnet releases and allows the door to close automatically via its closer. Licensed door hardware technicians and commercial electricians are the typical installers. The aluminum construction keeps the unit lightweight while providing a finish suitable for corridor and lobby applications.

The sem7850-al is suited for use in corridors, stairwells, and egress pathways where fire and life safety codes require doors to be held open during normal operations but automatically closed during an alarm event. It is commonly installed in schools, hospitals, office buildings, and multi-unit residential facilities. The holder integrates with low-voltage fire alarm control systems and smoke-activated release circuits.

Key Features

• Electromagnetic hold-open design releases automatically on power interruption
• Aluminum construction for a lightweight, corrosion-resistant finish
• Sentronic SEM series product line for consistent OEM-style replacement or new installation
• Compatible with standard door closer integration for automatic door control
• Low-voltage coil operation suitable for fire alarm and smoke detector circuit integration

Compatibility

Designed as an OEM-style electromagnetic door holder for use with commercial door closer systems in fire-rated door assemblies requiring automatic release on alarm.

Installation Notes

Installation should be performed by a licensed door hardware specialist or commercial electrician familiar with NFPA 80 fire door assembly requirements and local fire and life safety codes. Disconnect and lock out all power to the release circuit before wiring the unit. The door holder must be wired into an approved fire alarm or smoke detection release circuit so that the door closes fully upon alarm activation. Do not use this holder on a door assembly unless the paired door closer is rated and adjusted to reliably close and latch the door from the full hold-open position.

Technical Specifications

• Series: Sentronic SEM
• Material: Aluminum

Standard Information

• Brand: LCN
• Manufacturer Part Number: sem7850-al