System Sensor 6424 Projected Beam Smoke Detector

General

The System Sensor Model 6424 Beam Detector is designed to address the fire protection challenges in large open areas with high ceilings, such as atriums.

This detector operates on a four-wire, 24 VDC system. It consists of two components: a transmitter and a receiver. When positioned opposite each other, they can monitor a linear distance ranging from 30 feet to 330 feet. For larger areas, multiple units can be spaced between 30 and 60 feet apart. A trouble condition is signaled if 95% or more of the beam is obstructed, requiring the obstruction to be removed for the unit to reset.

Certifications/Listings: UL, ULC, California State Fire Marshal (7260-1209:141).

Visual Description of Detector: The product appears as a sleek, two-part infrared system, with one unit acting as the transmitter and the other as the receiver, typically mounted on opposite walls or ceilings.

Features

• Unique LED alignment technique for fast and easy setup.
• Four LEDs on the receiver front provide visual indication of maximum signal strength.
• No special meters or alignment tools are required.
• Receiver and transmitter can be powered independently or together.
• Detects a broad range of fire types.
• Includes ceiling and wall mount brackets.
• Calibrated test filters are included.
• Features Form A (Alarm) and Form B (Trouble) contacts.
• Option for a remote test station.
• Comes with a three-year warranty.

Applications

The System Sensor Model 6424 Beam Detector is particularly suitable for large or high-ceiling areas such as:

• Atriums
• Ballrooms
• Churches
• Warehouses
• Museums
• Factories
• Other areas where conventional smoke detectors are difficult to install.

Construction & Operation

The Model 6424 detector is a two-component infrared system comprising a separate transmitter and receiver. These units are mounted on opposite walls or ceilings to detect smoke within a linear path from 30 to 330 feet. The detector operates by sensing the reduction in the infrared beam's signal caused by smoke absorption and scattering, making it effective for both smoldering and fast-flaming fires.

The system features an LED alignment technique for straightforward setup, eliminating the need for special tools. Four LEDs on the receiver front guide the user to achieve optimal transmitter-receiver alignment for maximum signal strength and protection. An integrated automatic gain control compensates for signal degradation due to dust accumulation, component aging, and temperature variations.

Sensitivity can be selected at either 30% or 55% total obscuration. Calibrated test filters are provided for convenient sensitivity checks under various conditions. The operating temperature range is -22°F to 131°F (-30°C to 55°C). For detailed usage guidance, refer to document I56-506-00, "Guide for Proper Use of Beam Smoke Detectors."

Product Line Information

Specifications

Operational

• Range: 30' to 330' (length).
• Smoke Detector Spacing: On smooth ceilings, 60' between projected beams. Not more than one-half that spacing between a projected beam and a sidewall. Other spacing may be used based on ceiling height, airflow, and response requirements (refer to NFPA 72 A-5-3.5.5.2).
• Sensitivity: 30% ± 5% total obscuration OR 55% ± 5% total obscuration.
• Fault Condition (Trouble): Triggered by 95% or more obscuration, automatic gain control limit, or improper initial alignment.
• Test/Reset Features: Obscuration filter; local reset switch; remote test and reset switch capability (compatible with RTS451 test station).
• Indicators:
  • ALARM: Local red LED
  • TROUBLE: Local amber LED
  • NORMAL: Local flashing green LED
• Alignment Aid: Integral signal strength indication using 4 red LEDs.
• Relays: Alarm, Trouble. An EOL (End-of-Line) relay is required for power supervision.

Environmental

• Temperature: -30°C to 55°C (-22°F to 131°F).
• Humidity: 95% RH non-condensing.

Mechanical

• Dimensions:
  • Without bracket: 2.5" H x 8.5" W x 7" D.
  • With ceiling mount bracket: 5.5" H x 8.5" W x 7" D.
  • With wall mount bracket: 5.5" H x 8.5" W x 10" D.
• Weight: Receiver: 1.5 lb. (663 g). Transmitter: 1.3 lb. (598 g).
• Mounting: Separate ceiling and wall brackets provided.
• Wiring: Plug with attached cable.

Electrical (Receiver)

Electrical (Transmitter)

Engineering Specifications

The projected beam smoke detector is a 4-wire, 24 VDC device designed for use with UL-listed, separately supplied four-wire control panels. It is listed to UL 268 and comprises a transmitter and receiver that can be powered together or separately.

The detector supports operation in two modes: short range (30' - 100') and long range (100' - 330'). The beam's operating temperature range is -22°F to 131°F. Both the receiver and transmitter feature four alignment LEDs to facilitate proper unit alignment without specialized tools. The detector includes an automatic gain control to compensate for gradual signal reduction caused by dust accumulation on lenses, component aging, and temperature fluctuations. Both ceiling and wall mounting brackets are included. Testing is performed using calibrated test filters or a magnet-activated remote test station.

Wiring Diagrams

6424 Remote Outputs:

• POWER (+): Connected to WHITE-BROWN STRIPE wire.
• ALARM SIGNAL: Connected to WHITE-GREEN STRIPE wire.
• TROUBLE SIGNAL: Connected to WHITE-GREEN STRIPE wire (shared with Alarm Signal).
• POWER (-): Connected to ORANGE wire.
• AUX (-): Connected to ORANGE wire (shared with Power (-)).

Remote Test Station Connection:

• 6424 ALARM: Connects to RTS451 ALARM (WHITE-BROWN STRIPE).
• 6424 AUX (-): Connects to RTS451 AUX (-) (ORANGE).
• 6424 RESET: Connects to RTS451 RESET (BLUE).
• 6424 TEST: Connects to RTS451 TEST (YELLOW).

Transmitter & Receiver Powered Together (Class A Configuration):

• Return Loop: WHITE-YELLOW STRIPE, WHITE-RED STRIPE, WHITE-BLACK STRIPE, GRAY STRIPE.
• Initiating Loop: VIOLET, WHITE-VIOLET STRIPE, RED-WHITE STRIPE, WHITE-VIOLET STRIPE.
• Power to Detectors: BLACK (Receiver), BROWN (Receiver), ORANGE (Receiver), GREEN (Receiver). BLACK (Transmitter), BROWN (Transmitter), ORANGE (Transmitter), GREEN (Transmitter).
• UL Listed Panel Connections: Specific wiring to the panel is implied by the loop connections.
• EOL Resistor: Connected at the end of the initiating loop for supervision.
• EOL Power Supervision Relay Module: Shown energized, indicating power supervision is active.

Transmitter & Receiver Powered Separately (Class A Configuration):

• Return Loop: WHITE-YELLOW STRIPE, WHITE-RED STRIPE, WHITE-BLACK STRIPE, GRAY STRIPE.
• Initiating Loop: VIOLET, WHITE-VIOLET STRIPE, RED-WHITE STRIPE, WHITE-VIOLET STRIPE.
• Power to Detectors: BLACK (Receiver), BROWN (Receiver), ORANGE (Receiver), GREEN (Receiver). BLACK (Transmitter), BROWN (Transmitter), ORANGE (Transmitter), GREEN (Transmitter).
• UL Listed Panel Connections: Specific wiring to the panel is implied by the loop connections.
• EOL Resistor: Connected at the end of the initiating loop for supervision.
• EOL Power Supervision Relay Module: Shown energized, indicating power supervision is active.
• Optional Temporary Wiring for Transmitter Alignment Aid: Involves connecting GREEN, WHITE, BLUE, BROWN wires from a remote power source to the Transmitter.

Mounting Diagrams

Wall Mounting:

• Components: Horizontal Adjustment Screw (#10-24 x 1-3/8"), Metal Washer, Plastic Washer, Mounting Hub, Wall Mounting Bracket, Mounting Hole, Alignment Hubs, Alignment LEDs, Status LEDs (Receiver Only), Beam Lens, Hole Plug, "U" Bracket, Vertical Adjustment Screws (2), Cable Egress Hole Plug (used to plug unused hole), Alignment Adjust Potentiometer (Receiver Only).
• Description: Illustrates the assembly of the detector unit to a wall bracket, showing adjustment screws for horizontal and vertical positioning, and access to alignment LEDs and the potentiometer.

Ceiling Mounting:

• Components: Horizontal Adjustment Screw (#10-24 x 2-1/4"), Metal Washer, Plastic Washer, Ceiling Mounting Bracket, Mounting Hub, Mounting Holes, Alignment LEDs, "U" Bracket, Status LEDs (Receiver Only), Beam Lens, Hole Plug, Vertical Adjustment Screws (2), Cable Egress Hole Plug (used to plug unused hole), Alignment Adjust Potentiometer (Receiver Only).
• Description: Shows the detector mounted to a ceiling bracket, detailing similar adjustment mechanisms and access points as wall mounting.

Rear Views Showing Switches and Cables

Rear View, Receiver:

• Features: Access Door, Hole Plug, Sensitivity Select Switch (shown in 35% position), Alignment Mode Switch (shown in Normal Mode position), Reset Switch, Connector, Cable Exit Plug.
• Cable: 16-conductor cable, which can egress from either side.

Rear View, Transmitter:

• Features: Access Door, Hole Plug, Alignment Mode Switch (shown in Align Mode position), Connector, Cable Exit Plug, Range Select Switch (shown in Long Range position).
• Cable: 6-conductor cable.