Lcn sem7840-al Electromagnetic Door Holder Wall Mount

Product Description

The LCN sem7840-al is a wall-mounted electromagnetic door holder and release designed for use in fire and life safety door control systems. The unit operates as a two-component assembly: one component mounts to the wall and the other fastens to the door, with an electromagnetic field holding the door open when power is applied. Operating in fail-safe mode, the door releases automatically on power loss, supporting code-compliant fire door operation. Compatible with 120V AC, 12V DC, and 24V AC/DC power sources, the sem7840-al offers broad electrical flexibility for integration into building fire alarm and access control panels. The aluminum painted finish suits standard commercial interior applications.

This door holder is used in commercial and institutional buildings where fire-rated corridor and stairwell doors must be held open during normal occupancy and released automatically during a fire alarm event. It is a common component in NFPA 80 and NFPA 101 compliant door assemblies. The screw-in wall mounting style allows for straightforward installation on standard partition and masonry walls. The unit accommodates doors held open at various angles, making it adaptable to different traffic flow configurations in office, healthcare, education, and hospitality environments.

Key Features

• Fail-safe operation: door releases automatically when power is cut, supporting fire door compliance
• Multi-voltage input: accepts 120V AC, 12V DC, and 24V AC/DC power sources
• Maximum holding force of 35 pounds for reliable door retention
• Screw-in wall mounting with aluminum painted finish for clean commercial appearance
• Meets ANSI/BHMA 156.15 performance standards and is UL Listed
• Compact lock body: 1 inch deep, 2-13/16 inches wide for low-profile wall profile

Compatibility

The sem7840-al is part of the LCN 7800 series and is designed as a wall-mounted OEM-style electromagnetic door holder for integration with fire alarm systems and door control circuits requiring 120V AC, 12V DC, or 24V AC/DC activation.

Installation Notes

Installation is typically performed by a licensed door hardware specialist, electrician, or qualified contractor familiar with NFPA 80 fire door assembly requirements. Disconnect and lock out all power sources before wiring the unit to the building electrical or fire alarm circuit. Ensure wall substrate and mounting location comply with the door manufacturer and authority having jurisdiction requirements for fire-rated assemblies. Do not modify the electromagnetic components or override the fail-safe release mechanism.