System Sensor HWL-LF/HRL-LF Low Frequency Wall Sounder - White

System Sensor HWL-LF/HRL-LF Low Frequency Wall Sounder

The System Sensor HWL-LF/HRL-LF Low Frequency Wall Sounder is a 24V indoor fire-notification appliance designed to produce a 520 Hz ± 10% square-wave tone for sleeping-space applications. Available in white as the HWL-LF or red as the HRL-LF, it supports wall mounting, selectable tone patterns, and high or low output settings.

Designed for hotels, dormitories, apartments, healthcare facilities, and other occupancies requiring low-frequency audible signaling, this L-Series sounder gives installers a compact 2-wire wall-mount solution with plug-in construction. A rotary selector provides Temporal 3, Temporal 4, continuous, and coded tone options, while selectable volume supports different notification requirements. Its universal mounting plate also simplifies wiring continuity checks before the sounder is installed.

The sounder operates from 16 to 33 V with 24 V nominal power and accepts 12 to 18 AWG field wiring. It is electrically compatible with legacy SpectrAlert and SpectrAlert Advance notification appliances and supports the MDL3 SyncCircuit module. The HWL-LF and HRL-LF are UL-listed wall sounders for fire-protective service, with additional FM and CSFM approvals documented for the L-Series low-frequency platform.

Key Features

• 520 Hz Low-Frequency Tone: Produces a 520 Hz ± 10% square-wave audible signal for low-frequency fire-notification applications.
• Red and White Variants: Choose the white HWL-LF or red HRL-LF to match installation requirements.
• Selectable Tone Patterns: Supports Temporal 3, Temporal 4, continuous, and coded operating modes.
• High and Low Volume: Provides selectable output levels up to 80 dBA UL reverberant at the high setting.
• Plug-In Installation: Minimizes intrusion into the back box for faster installation and reduced wiring interference.
• Continuity Test Support: The mounting plate incorporates a shorting spring for checking field wiring before installing the device.
• Legacy Compatibility: Electrically compatible with SpectrAlert and SpectrAlert Advance notification appliances.

Technical Specifications

• Brand: System Sensor
• Series: L-Series
• Product Type: Low Frequency Wall Sounder
• White Variant: HWL-LF
• Red Variant: HRL-LF
• Alarm Type: Audible
• Connectivity: Wired, 2-wire
• Mounting: Indoor wall mount
• Frequency Range: 520 Hz ± 10%
• Waveform: Square wave
• Tone Patterns: Temporal 3, Temporal 4, continuous, coded
• Volume Settings: High and low
• UL Reverberant Sound Output: 80 dBA high, 76 dBA low
• Nominal Voltage: 24 V DC/FWR
• Operating Voltage Range: 16 to 33 V
• MDL3 SyncCircuit Operating Range: 16.5 to 33 V
• Maximum Current Draw, High Setting: 111 mA DC, 151 mA FWR
• Maximum Current Draw, Low Setting: 80 mA DC, 76 mA FWR
• Input Terminal Wire Gauge: 12 to 18 AWG
• Operating Temperature: 32°F to 120°F
• Humidity Range: 10% to 93% non-condensing
• Dimensions: 5.6" L x 4.7" W x 1.5" D
• Compatible Back Boxes: 4" x 4" x 1.5" back box, 4" octagon back box, double-gang back box, or single-gang 2" x 4" x 1.9" back box for 2-wire installation
• UL Listing: UL 464, S4011
• FM Approval: PR452768
• CSFM: 7135-1653:0516
• Country of Origin: Mexico