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ESL by Interlogix 4-Wire Smoke & Heat Detector with EOL Relay

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Detect Fire In Different Three Ways

Designed for connection to an alarm panel that accepts 4-wire fire inputs, the ESL 4-Wire Smoke & Heat Detector (with EOL Relay) integrates reliable, self-diagnostic smoke and heat detection into your security system. As part of the 541 Series, the photoelectric detector features drift compensation and more to enhance performance and reduce false alarms. This model also offers a built-in EOL relay to supervise the unit’s power status.

  • Built-in fixed/rate-of-rise heat detector
  • Triggers alarm through security system when activated
  • EOL relay can supervise the power status
  • Drift compensation reduces time between cleanings

The combination smoke/heat detector offers superior protection compared to standard detectors, because it detects fire in three different ways: smoke detection, fixed heat detection, and rate-of-rise heat detection.

About Heat Detection

There are three main types of heat detectors: fixed temperature, rate-of-rise, and combo. Fixed temperature detectors trigger a fire alarm when the ambient temperature reaches a specific temperature, which is ideal for detecting fires that develop slowly. Rate-of-rise detectors trigger an alarm when the ambient temperature quickly rises, ideal for detecting fires that develop quickly. Combination heat detectors, like this unit, use both technologies.

Advanced Cleaning Features

The detector uses built-in drift compensation to increase the amount of time between cleanings and reduce false alarms. Drift compensation automatically adjusts the detector’s sensitivity as it gets dirty with time.

When the detector finally needs cleaning, you can easily replace its optical chamber and continue relying on the unit without worry.

Self-Supervised to Reduce Downtime

All 500 Series smoke detectors self-supervise their sensitivity and operational status to provide visual and system alerts if they fall out of the appropriate sensitivity range or fail internal diagnostic tests. This meets NFPA 72 field sensitivity testing requirements without the need for external meters.

How It Works

500 Series smoke detectors work on the photoelectric light-scattering principle. A pulsed infrared (IR) LED provides the light source, and a high-speed photodiode serves as the sensor. This technology offers superior protection against false alarms caused by dust, bugs, RF interference, and ambient light.

Note: Not designed for standalone use; must be connected to an alarm panel.

Increase Your Safety & Security With Interlogix

Formerly GE Security, Interlogix’s robust product offering is designed to protect and secure your business, your home, and your family. Their products are leading the industry in innovation and reliability. Whether it’s a complete system, access control, motion detection, or simple magnetic contacts, Interlogix has the products that will meet your security needs.

Technical Details


  • Power Supply: 8.5-33VDC (12/24 V operation) polarity sensitive
  • Max. Ripple (6/12/24V): 10 percent (Vpk-pk)
  • Avg. Standby Current: 70 µA
  • Typical Alarm Current (6/12/24V): Up to 60 mA max if not limited by control panel
  • Alarm Contacts: 500 mA at 36 VDC (resistive)
  • Alarm Current (mA): 35
  • Photoelectric Sensitivity: 3.1 percent + 0.5 – 1.0 percent


  • Operating Temperature: 32° to 100° F (0° to 37° C)
  • Operating Humidity: 0 to 95 percent non-condensing
  • RFI Immunity: 20 V/m min; 0-1000 MHz


  • Color: White
  • Field Wiring Size: 12-18 AWG (16-22 recommended)
  • Heat Detector:
    • Rate-of-Rise: 15° F/min and > 105° F (8.3° C/min and > 40.6° C)
    • Fixed Threshold: 135° F (57.2° C)
  • UL 2-Wire Compatibility Identifiers: S09A, S10A, S11A
  • Drift Compensation Adjustment: 1 percent feet max.
  • Detector Head Dimensions: 5.5(D) x 2(H) inches (14.0 x 5 cm)
  • Mounting Dimensions: 5.25(Dia.) x 0.3(H) inches (13.3 x 0.8 cm)


  • Reset Time: 1 second minimum
  • Listings:
    • 500N Series: UL 268 cUL, CSFM
    • 521B, 521BXT, 541C, 541CXT: UL 268, CSFM
    • 528B, 528BXT, 548C, 548CXT: ULC