LCN SEM7840 Low-Profile Recess...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$591.00
$338.13
LCN LCN SEM7840 Low-Profile Recessed Wall Mount Heavy Duty Door Holding Magnet - Powder Coat Finish LCN-SEM7840

LCN SEM7840 Low-Profile Recessed Wall Mount Heavy Duty Door Holding Magnet with 35 Pound Holding Force

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Model: SEM7840-689
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In Stock (leaves warehouse same day if ordered before 3pm ET)

$591.00
$338.13
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LCN SEM7840 Low-Profile Recessed Wall Mount Heavy Duty Door Holding Magnet with 35 Pound Holding Force

Professional Fire Safety Door Control Solution

The LCN SEM7840 is a low-profile recessed wall-mounted door holding magnet from the Sentronic 7800 Series, engineered for fire safety applications. This heavy-duty magnet provides 35 pounds of holding force through tri-voltage design and releases automatically when fire alarm panels enter alarm condition. UL listed for metal smoke barrier or labeled fire doors and certified under ANSI/BHMA A156.15, the SEM7840 features die-cast housing construction with powder coat finish for long-term durability in commercial applications.

Professional Features & Benefits

  • Heavy-Duty Holding Force: Tri-voltage design delivers 35 pounds of holding force for secure door positioning in fire safety applications.
  • Fail-Safe Operation: Magnet holds door until electrical current is interrupted, then releases automatically to allow manual door operation during alarm conditions.
  • Low-Profile Recessed Design: Wall-recessed mounting provides clean installation appearance while maintaining full functionality for pocket door applications.
  • Die-Cast Housing Construction: Heavy-duty die-cast housing with powder coat finish ensures long-term durability in demanding commercial environments.
  • Fire Safety Compliance: UL listed for metal smoke barrier or labeled fire doors and meets ANSI/BHMA A156.15 standards for code compliance.
  • Versatile Installation Options: Suitable for pocket door installations with wood and machine screw pack fasteners included, armature extensions available.
  • Manufacturer Warranty: Protected by 2-year warranty for added confidence and protection.

Technical Specifications

  • Refer to manufacturer documentation for complete technical specifications.

Installation & Operation

  1. Verify electrical requirements match available power supply. Confirm tri-voltage compatibility and current capacity before proceeding.
  2. Disconnect power supply before beginning installation. Follow all applicable electrical codes and safety procedures.
  3. Mount the unit in the specified recessed wall location ensuring adequate clearance for wiring access, ventilation, and future service requirements.
  4. Route and connect wiring according to manufacturer wiring diagrams. Use appropriate wire gauge and connectors for the application.
  5. Configure operational settings including fail-safe operation per fire safety application requirements.
  6. Restore power and test all functions including normal holding operation, alarm release function, and integration with fire alarm systems.
  7. Complete final inspection and document settings. Refer to manufacturer documentation for complete wiring diagrams, programming instructions, and troubleshooting.

Professional Applications

  • Commercial Building Fire Safety Systems
  • Healthcare Facility Fire Door Control
  • Educational Institution Safety Compliance
  • Industrial Facility Fire Protection
  • Multi-Tenant Residential Fire Safety
  • Government Building Code Compliance
  • Hospitality Fire Safety Systems

Why Choose LCN Quality?

LCN SEM7840 door holding magnets deliver professional-grade reliability with die-cast housing construction and UL listing for fire safety applications. Protected by a 2-year warranty and certified under ANSI/BHMA A156.15 standards for code compliance. Engineered for demanding commercial fire safety applications where dependable automatic release performance is essential.

Product Documentation & Resources

Product Specs

Series:
SEM 7800 Series
ADA Compliant:
Yes
Mounting Detail:
Surface - Magnet
Warranty:
2 Year
BAA Qualified:
Yes
Subcategory:
Fire and Life Safety Closers
Product Group:
Door Controls
Product Subgroup:
Electromagnetic Door Holder / Releases
Product Type:
Door Magnets
Door Type:
Interior Door
Finish Type:
Powder Coat
Commercial/Residential:
Commercial
Electronic:
Yes
Tags:
lcn sem7840, sem7840
Product Model:
SEM7840
Product Voltage:
12V/24V/120V
Mounting Method:
Wall Mount
Product Projection:
6-3/4"
Product Category:
Door Controls
Department:
Door Hardware

LCN SEM7840-689 – Frequently Asked Questions

1) What is the LCN SEM7840 low profile recessed wall mount door holding magnet used for?
This heavy-duty electromagnet holds open fire doors, commercial doors, and security doors. It releases automatically when fire alarm systems activate. Common in hospitals, schools, offices, and multi-story buildings where doors must stay open during normal use but close during emergencies.
2) What door types and weights is this magnet compatible with?
Works with steel doors, wood doors with steel plates, and aluminum doors. Check door weight capacity in manufacturer specifications. Verify door material contains ferrous metal for magnetic attraction. Non-ferrous doors require steel strike plates.
3) Does this work for left-hand and right-hand door installations?
This unit works for both left-hand and right-hand doors. The low profile design mounts flush in wall. Position determines door swing direction compatibility. Verify clearances and door travel path before installation.
4) What finish options are available for the SEM7840?
This model features powder coat finish for durability and corrosion resistance. Standard finish matches most commercial hardware. Powder coating provides long-lasting protection in high-traffic areas and various environmental conditions.
5) What electrical specifications does this door magnet require?
Verify voltage and amperage requirements in product documentation. Most commercial door magnets operate on 12V or 24V DC systems. Connect to fire alarm panel or access control system. Consult electrical specifications before wiring.
6) Are there building code requirements for electromagnetic door holders?
Yes. Fire code requires automatic release when fire alarm activates. Installation must comply with NFPA 80 and local fire codes. Some jurisdictions restrict use on certain door types. Check with local AHJ before installation.
7) What components are included with the SEM7840 package?
Package typically includes magnet assembly, mounting hardware, and installation instructions. Separate electrical connections and conduit may be required. Verify all components against packing list upon delivery.
8) How is this low profile magnet installed in the wall?
Requires recessed mounting in wall cavity. Cut opening per manufacturer template. Run electrical wiring to location before installation. Secure unit with provided fasteners. Test alignment and holding strength before final adjustment.
9) What maintenance does this electromagnetic door holder require?
Clean magnet face regularly to remove debris and metal particles. Test release function monthly with fire alarm system. Check mounting screws for tightness. Inspect wiring connections annually. Replace unit if holding strength decreases significantly.
10) What other LCN door control products work with this magnet?
Works with LCN door closers, exit devices, and access control systems. Compatible with most fire alarm panels that provide appropriate power output. Check our door hardware section for complete LCN product families.
11) Can this magnet be adjusted after installation?
Limited adjustment available after installation due to recessed mounting. Proper positioning during initial installation is critical. If major adjustments needed, may require reinstallation with new wall opening. Plan carefully using manufacturer templates.
How fast can I get the LCN SEM7840-689 delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the continental U.S. Need it urgently? Contact Us for expedited shipping options.
Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit, reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the LCN SEM7840-689 come with a warranty?
Absolutely. The LCN SEM7840-689 is backed by a manufacturer’s warranty. For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the LCN SEM7840-689?
You can call, text, or email our expert support team for fast answers. We’re here to help with product selection, installation tips, and troubleshooting. Contact Us
Why buy the LCN SEM7840-689 from ZenSupply?
ZenSupply makes it easy to get the commercial door hardware you need—fast shipping, expert support, and rewards on every order. Our team is always ready to help you choose the right product for your project.

Product Reviews

  • 5
    A Magnetic Solution: Keeping Doors in Place with Ease!

    Posted by Marshll on Apr 11th 2024

    This low-profile recessed wall-mount heavy-duty door holding magnet from Zensupply is a game-changer. One thing I love is its sleek design - blends right in! But, gotta mention, installation might need a bit of elbow grease. Overall, solid product!

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