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Part of the FSX family of electro-optical flame detectors, the FS20X represents a quantum leap in integrating infrared and ultraviolet sensing technologies.

Features & Benefits

Detects hydrocarbon and non-hydrocarbon fuel fires in all environmental conditions

Range greater than 200 feet to 1 sq. ft. heptane fire

Arc welding immunity 

Quick Specs

Field of view: 90° full 100% core of vision, ± 45° from on axis

Operating voltage: 24 VDC nominal (18-32 VDC) - regulated

Sensitivity: Very high, high, medium and low - switch selectable 

Product Overview

Based on the foundation of the highly successful and reliable Fire Sentry SS4 Flame Detector, the Fire Sentry FS20X Flame Detector represents a quantum leap in integrating Infrared and Ultraviolet sensing technologies. The Fire Sentry FS20X is a Multi-Spectrum and UV/Dual IR/VIS Flame Detector with a proven UV solar-blind sensor. The Fire Sentry FS20X exhibits faster false-alarm free response to fires over a wider temperature range and with a much longer detection range compared to conventional UV/IR detectors.

Conventional and older technology UV/IR detectors, using narrow band 4.3 micron IR sensors, will not respond to smoky fires or if the detector lens is contaminated with oil and other substances since both UV and 4.3 micron signals are attenuated, obscured or absorbed by thick smoke or detector lens contaminants. Also, these old technology UV/IR detectors will not alarm to any fire if they are installed behind ordinary window glass.

The Fire Sentry FS20X Flame Detector uses advanced patented algorithms for signal processing and fire and flame analysis is designed to alarm to all types of fires in all industrial environmental conditions. If the detector’s UV signal is degraded due to heavy smoke or a contaminated lens, the Fire Sentry FS20X’s patented* WideBand IR™, Near Band IR and Visible sensors will still alarm to fire but at a reduced sensitivity and slower response time.

Dual microprocessors provide a high level of fail-safe operation combined with fast and reliable performance. The Master Microprocessor performs high-speed digital sampling and signal processing calculations; while the slave microprocessor handles various sensor data, performs communications, self-diagnostics and provides interface versatility; and additional memory for storing Event Log and FirePic™ data.

The Fire Sentry FS20X Flame Detector has a detection range in excess of 200 feet (very high sensitivity setting) for the detection of a one square-foot Heptane reference fire and has a cone of vision greater in volumetric coverage than most UV/IR detectors. This means fewer detectors can be used as compared to other manufacturers’ detectors.

Additional Features and Benefits

Patented* WideBand IR™ Infrared combined with Ultraviolet

Detection range greater than 200 feet to 1 sq. ft. heptane fire

Patented* Electronic Frequency Analysis

Visible Sensor for optimum false alarm rejection

Selectable detection sensitivities

Solar blind 90° full 100% cone-of-vision

Dual Microprocessors for reliable performance

Real-time clock for accurate time dating of events

FirePic™ — Up to 6 pre-fire event data storage

Event log — Up to 200 events with date and time stamp

Built-in RS-485 ModBus Communication

Built-in non-isolated 4-20 mA analog output (sink or source)

Alarm, Fault and Fire Verification relays.

Automatic Optical Path and Electronic Self-Test

Widest operating temperature range

Patented* Electronics Module for components protection with plug-in terminations for easy field installation

Two ¾” NPT OR 25mm conduit entries

Low power consumption

High RFI and EMI immunity

FM approved


Detects hydrocarbon and non-hydrocarbon fuel fires in all environmental conditions

Arc welding immunity

False alarm rejection for all environmental conditions

Minimal maintenance for trouble-free operation

PC software and Interface Module (FSIM) for fault diagnostics real-time graphs (RTGs), and downloading of FirePics™ and event log

Suitable for a wide variety of applications