System Sensor HCWL2-LF Ceiling Mount Sounder, Low Frequency, White

The System Sensor HCWL2-LF is a white, ceiling-mounted low-frequency fire alarm sounder from the second-generation L-Series, designed for audible emergency notification in sleeping areas and commercial buildings. Operating on 24VDC nominal power with a 16-33VDC operating range, it produces a 520 Hz 10% square-wave tone to address NFPA 72 sleeping area notification requirements. The sounder features eight selectable tone and volume settings, up to 78 dBA reverberant sound output, digital voltage meter test points, and a plug-in mounting plate with wiring continuity verification.

System Sensor HCWL2-LF L-Series 520 Hz Ceiling-Mount Low-Frequency Fire Alarm Sounder

The System Sensor HCWL2-LF Low-Frequency Sounder provides audible fire alarm notification through a 520 Hz 10% square-wave signal designed to address NFPA 72 requirements for sleeping areas. Part of the second-generation L-Series, the sounder generates low-frequency emergency tones intended to improve occupant notification during nighttime emergencies. Its white, round enclosure supports ceiling-mounted installations in hotels, dormitories, apartment buildings, healthcare facilities, and other protected sleeping environments. The HCWL2-LF is an audible-only notification appliance without an integrated strobe, allowing visual notification to be provided separately where required by the fire alarm system design.

The HCWL2-LF operates on a regulated 24VDC nominal notification appliance circuit (NAC) with a 16-33VDC operating range. Its rotary selector provides eight tone and volume configurations, including Temporal-3, Temporal-4, continuous, and coded operation with high and low output settings. The sounder delivers 78 dBA reverberant output at the high setting and 74 dBA at the low setting, according to the manufacturer's UL sound output data. Current consumption ranges from 78mA to 82mA, depending on the selected operating mode. Temporal-3 signaling supports fire alarm notification, while Temporal-4 provides a compatible carbon monoxide notification pattern. Coded operation requires the connected notification appliance circuit to supply the appropriate signaling pattern.

The System Sensor HCWL2-LF measures 6.80 inches in diameter and 1.63 inches deep, providing a low-profile ceiling installation with a white finish. Its plug-in design uses a universal mounting plate with an integrated shorting spring, allowing installers to verify wiring continuity before attaching the sounder. The mounting terminals accommodate 12-18 AWG field wiring, while integrated digital voltage meter test points allow electrical measurements without removing the installed appliance. The sounder supports installation with compatible electrical boxes and the optional System Sensor SBBCWL ceiling surface-mount back box. Its operating temperature range is 32 F to 120 F (0 C to 49 C), with a relative humidity range of 10-93%, noncondensing.

The HCWL2-LF integrates with compatible fire alarm control panels, notification appliance power supplies, and System Sensor synchronization equipment. Synchronization is supported through approved power supplies using the System Sensor Sync protocol or a compatible MDL synchronization module. The sounder is electrically compatible with supported legacy SpectrAlert Advance and L-Series notification appliances, allowing integration into existing fire alarm installations when circuit requirements are satisfied. The HCWL2-LF replaces the earlier HCWL-LF ceiling sounder and provides updated second-generation diagnostic and installation features. The L-Series carries applicable UL/ULC, FM, and California State Fire Marshal approvals, subject to the listed configuration. Sound output selection, circuit loading, mounting, and system testing must follow the manufacturer's instructions and applicable NFPA 72 requirements.