The FIREYE 85UVF1A-1QDK3 is a microprocessor-based, self-checking ultraviolet (UV) flame scanner from the Fireye Phoenix Series 2 family. It is built for industrial combustion environments where flame detection must be fast, stable, and resistant to false signals. Unlike older “amplifier + scanner head” architectures, the Phoenix Series 2 concept integrates key functions directly in the scanner: it includes an internal flame relay, automatic ON/OFF thresholding, and a standard 4–20 mA flame strength output, reducing wiring complexity while improving diagnostic visibility.
This specific model code matters. The “QD” portion indicates an 8-pin electrical quick-disconnect connection, enabling a cleaner service workflow and consistent field wiring with dedicated cable assemblies (59-546-x series). The “K3” suffix identifies an enhanced optical filter variant that extends the effective UV sensitivity beyond the classic deep-UV band, allowing the scanner to detect wavelengths up to 500 nm rather than staying limited to the standard UV range. Fireye positions the K3 option as especially useful for steel plant applications (for example, burners firing blast furnace gas and coke oven gas) where flame characteristics can make standard UV discrimination more challenging.
At the heart of the Phoenix Series 2 approach is a simple idea: don’t just look for “light,” look for flame flicker. The scanner analyzes the amplitude of flame modulation across a wide frequency range, then automatically stores the target flame signature during setup to determine the best switching thresholds. This method helps reject many non-flame light sources and improves repeatability across real-world burner conditions.
Where 85UVF1A-1QDK3 fits in a Burner Management System
In a typical Burner Management System (BMS) or PLC-based burner safety architecture, the 85UVF1A-1QDK3 serves as the “eyes on the flame.” It provides:
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A discrete flame relay output for permissive/interlock logic
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A fault relay for maintenance and safety annunciation
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A 4–20 mA analog signal for trending flame quality, commissioning, and predictive maintenance
The scanner includes a local keypad and status LEDs for fast setup and on-site troubleshooting, but it is also designed for remote interfacing through those discrete and analog outputs.
One important application boundary: Fireye states they do not recommend Phoenix scanners for small pilot flames or obstructed sighting. In practice, that means you should plan line-of-sight and scanner placement carefully, and validate performance during commissioning rather than assuming any UV sensor will work everywhere.
Key Specifications and Features (Model-Focused)
| Category | FIREYE 85UVF1A-1QDK3 Details |
|---|---|
| Product Type | Phoenix Series 2 integrated, self-checking UV flame scanner with internal flame relay |
| Power | 24 VDC powered |
| Connection | 8-pin quick-disconnect (QD); QD models use 59-546-x cable assemblies |
| Flame Detection Band | UV models: 295–340 nm; K3 models: 310–500 nm (extended range) |
| Flame Signal Philosophy | Measures flame flicker modulation; stores target flame and auto-determines ON/OFF thresholds; auto-selects sensor gain |
| Outputs | Internal flame relay + fault relay; 4–20 mA flame strength output standard |
| FFRT | User-set Flame Failure Response Time; factory preset 1 second; selectable via keypad (LEDs indicate 1–4 seconds) |
| Background Flame Handling | Optional “learn background flame” function shifts OFF threshold to exclude background condition |
| Safety Integrity | Fireye indicates Phoenix 85 series suitable for installations up to SIL 3 (per Exida FMEDA reference) |
| Typical Applications | Duct burners, industrial gas burners, refinery applications, Low NOx burners, waste gas units, incinerators; K3 especially for certain steel plant fuels |
Why the K3 Option Matters (and when it’s worth paying for)
Standard UV flame scanners often focus on deep-UV emissions that are strong in many clean gas flames. Real plants, however, are messy ecosystems: changing fuel blends, unusual combustion chemistry, high background radiation, and challenging sighting angles can all reduce margin. The K3 optical filter variant is designed to shift optical sensitivity so the scanner can pick up additional wavelengths, extending detection capability up to 500 nm.
Fireye explicitly notes K3 suitability for some steel plant burner applications such as blast furnace gas and coke oven gas, where flame signatures can differ from “textbook” flames. That doesn’t mean K3 is automatically better in every application—only that it gives you another lever when the standard UV approach is marginal.
Commissioning and Setup: Practical Advantages
The Phoenix Series 2 scanners are designed so setup can be completed quickly through a local keypad using “learn” routines:
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Aim mode sets the scanner to maximum gain while you physically adjust sighting to maximize flame signal strength. Fireye’s commissioning guidance suggests targeting at least a few strength LEDs as a minimum signal margin.
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Target flame learning stores the modulation signature and automatically determines suitable switching thresholds, reducing manual tuning and helping standardize commissioning across multiple burners.
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Background flame learning (optional) lets the scanner discriminate between a target flame and persistent background flame by shifting the OFF threshold to exclude the background condition. This is particularly valuable in multi-burner furnaces where adjacent flames can create a constant “glow” in the scanner’s view.
The scanner’s FFRT (Flame Failure Response Time) is also configurable. Units ship from the factory preset to 1 second, and you can change the setting through the keypad. The installed FFRT can be verified during operation by holding the UP button and reading which LED is lit (1st through 4th LED correspond to FFRT in seconds).
Wiring and Integration Notes (QD Cabling and I/O)
The 85UVF1A-1QDK3 uses the 59-546 family of 8-conductor cable assemblies with an 8-pin female connector, available in multiple standard lengths (from 3 meters up to 90 meters). This supports consistent wiring practices across projects and simplifies replacement because the scanner head itself is not hardwired with captive cable. Fireye also provides connector pin/function mapping and color codes to help standardize panel wiring for 24 VDC supply, relay contacts, and the 4–20 mA loop.
Common mounting flange accessories include NPT/BSP 1-inch threaded mounting flanges and heat-insulating flange variants, which help manage scanner temperature exposure in hot burner fronts.
Summary: What You’re Buying with the 85UVF1A-1QDK3
The FIREYE 85UVF1A-1QDK3 is a strong fit when you need a modern UV flame scanner that is:
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Integrated (internal flame relay + 4–20 mA output) to reduce architecture complexity
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Service-friendly (8-pin quick disconnect, standardized cable assemblies)
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Commissioning-efficient (learn routines, background discrimination option, selectable FFRT)
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Application-ready for demanding industrial burners, including cases where the K3 optical filter adds detection margin for difficult fuels or environments .
