Liftmaster LM21AFCB Advance Fire Control Release Device

Advanced Fire Release Control for Motorized and Manual Door Systems

The LiftMaster LM21AFCB is a UL-listed fire control release device engineered to automatically close motorized or manual fire-rated doors in the event of an alarm or power loss. Designed for dry indoor installations, the LM21AFCB offers programmable delay settings, auxiliary limit switch support, 3-cycle obstruction logic, and an integrated annunciator connection. It supports up to four smoke detectors and includes diagnostic LEDs and remote test/reset capabilities for streamlined maintenance and testing.

Key Features

• Automatically releases doors during fire alarms or power loss
• Selectable time delays: 10, 20, 30, or 60 seconds
• Supports up to four smoke detectors (2-wire or 4-wire)
• 3-cycle obstruction detection logic with auto-drop option
• Voice board and annunciator compatible
• Remote test/reset switch connection included
• Diagnostic LEDs for power, battery, faults, and system status
• Battery backup supported (2× 12V sealed lead-acid batteries)

Technical Specifications

• Model: LM21AFCB
• Power Input: 120 VAC, 60Hz
• Standby Current: 0.20A | Alarm Current: 0.60A
• Battery Backup: 24V (2× 12V 4.5–5.0AH SLA batteries)
• Load Rating: Supports and releases up to 40 lbs
• Auxiliary Relay Output: 0.5A @ 125 VAC / 1A @ 24 VDC
• Dimensions: 10" H × 10" W × 5" D
• Environment: Indoor dry location only
• Compliance: UL / ULC listed, NFPA 72 and 80 compliant

Conclusion

The LiftMaster LM21AFCB delivers advanced, code-compliant protection for fire-rated doors, integrating programmable delay, monitoring, and reset functions into a single reliable unit. Whether used with motorized or manual doors, it ensures safe and efficient emergency response in commercial or industrial settings.