Fireye InSight S4 95S4 UV/IR Integrated Flame Scanner

A UV or IR solid-state flame scanner with OLED display, four files and Auto Config

The Fireye InSight S4 95S4 (InSight Series IV, Type 95) is a fully microprocessor-based integrated flame scanner that combines flame detection, amplification, safety determination and the flame switch function in a single detection head, so no separate amplifier or flame switch module is needed to interface with the burner management system. It is a solid-state detector scanner using either a UV or an IR detector, and Fireye describes it as incorporating the detection and discrimination elements of the InSight II with some enhanced features.

During setup the scanner measures the amplitude of the modulations, the flame flicker, inside the targeted flame and selects the modulation frequency that gives the best flame ON/OFF discrimination. Frequency and sensor gain can be selected manually or automatically. Standard features include an independently adjustable flame relay, 21 modulation frequency choices, adjustable ON/OFF thresholds, a 4 to 20 mA signal strength output, a fault relay, four selectable programmable files for different fuels or firing rates, and Auto Config with manual override.

Technical specifications

Choosing the version

Select UV for gas and IR for oil or coal, then the connector style that matches the cable already installed: the -1WINC versions fit InSight I wiring, and the -1 and -2 versions fit InSight II wiring. Choose a -2 model where a Form C flame relay is needed and a CEX model for terminal-block wiring in flameproof housings. Fireye also offers fiber optic mounting for extended viewing and the optional Fireye Explorer PC software (CU-109) for remote communication.

Aim the scanner so that its line of sight crosses the burner centre line at a slight angle (about 5 degrees) and sees the primary combustion zone; the OLED feedback assists alignment. If one scanner serves both pilot and main flame, the line of sight should also intersect the ignitor flame. Related equipment is listed under burners and gas trains and flame detection; compare the LAMTEC FFS08 flame sensor.

Installation checks for the 95S4 scanner

Before the scanner is fitted, confirm that the sight pipe gives a clear, unobstructed view of the primary combustion zone at every firing rate the burner will run, not only at high fire. Mount the scanner through the mounting flange ordered for the job and route the 12-conductor cable away from ignition transformer leads and high-voltage wiring so the flame signal and the 4-20 mA output are not disturbed by induced noise. Keep the cable run within the length stated in the Fireye bulletin and terminate it according to the wiring diagrams for the specific part number, since the -1, -2, -1WINC and CEX versions use different connection methods.

Connect purge air to the 3/8 inch connection from a clean, dry source. On sites where instrument air is not available, the air supply should still be filtered so that it does not carry oil mist or dust onto the viewing window.

Commissioning with Auto Config and the four files

Commissioning is best done with the burner running under stable conditions. Use Auto Config to let the scanner pick the modulation frequency and gain for the target flame, then check the result manually: shut the fuel, or view a background condition such as a neighbouring burner, and make sure the scanner reports flame OFF with a clear margin below the ON threshold. Where the four programmable files are used for different fuels or firing rates, each file should be set up and tested with the fuel and load it is meant to cover, and the switching between files checked against the burner management system logic.

Record the settings for each file in the commissioning sheet so that a replacement scanner can be configured to match without guesswork. The OLED display and the five pushbutton keys give the information needed for this, and the optional Fireye Explorer software can be used where remote communication is wanted.

Operating in Oman and GCC boiler houses and process heaters

Boiler rooms and fired heaters in the Gulf region often combine high ambient temperature, fine airborne dust and, near the coast, humid salt-laden air. Check that the temperature at the scanner location stays inside the published ambient range during summer operation; a scanner mounted close to a hot furnace front can run much hotter than the room itself. Increase purge air towards the upper value given in the bulletin when the scanner sits near its upper temperature limit or when dirty fuels are fired, as this both cools the head and keeps the lens clean. The IP66 housing helps against dust and washdown, but cable glands and the connector must be fitted and tightened correctly to keep that protection.

Routine maintenance

Include the scanner in the burner maintenance routine: inspect and clean the viewing lens, check that the purge air is flowing, look for damage to the cable and connector, and compare the displayed flame signal with the values recorded at commissioning. A steady fall in signal strength usually points to a dirty sight path or a change in flame shape and should be investigated before it causes nuisance trips. After any burner modification, repeat the flame ON/OFF discrimination test.

Documents and quotation

The attached Fireye bulletin CU-120 (November 2025) covers the model listing, specifications, installation, wiring and the programming menus. Send the full part number, sensor type, connector, flange and cable length for a quotation, and confirm the exact model and approvals before ordering.