The FIREYE 95DSS2-1 is an integrated, microprocessor-based flame scanner that combines dual-sensor detection (infrared + ultraviolet) with an internal flame relay, allowing it to perform flame proving without a separate remote flame amplifier in many control architectures. It belongs to Fireye’s InSight Type 95 scanner family, which is designed to detect the presence or absence of a target flame in single- or multi-burner combustion systems by analyzing flame flicker modulation rather than simply measuring light intensity.
What makes the 95DSS2-1 especially valuable is the Expanded Model S2 feature set. Compared with S1 models, S2 adds AutoTune automatic programming with manual override, expands modulation frequency choices to 21, increases internal memory to four selectable programmable files, and adds remote communications capability. These capabilities are not cosmetic; they are engineering tools that reduce commissioning time, improve discrimination in challenging furnaces, and support consistent performance across different fuels and firing rates.
Why “Dual IR/UV” matters in real burners
Dual-sensor scanners are commonly selected when flame signatures vary significantly across operating conditions or fuels. The Type 95 family includes IR-only and UV-only models, but the 95DS class contains both IR and UV sensors in one housing. For the dual-sensor models, the scanner can operate on the sum of both IR and UV signals, improving signal robustness, and it also allows selecting IR-only or UV-only if the application demands it. This flexibility can be useful when background radiation or process glare affects one band more than the other, or when commissioning reveals that one sensor provides a cleaner flame ON/OFF ratio.
A smarter definition of “flame present”: modulation and discrimination
InSight scanners measure the amplitude of flame modulation (flame “flicker”) and select a modulation frequency that yields the best discrimination between flame ON and flame OFF conditions. In S1 models, frequency and gain are typically manual choices; in S2 models, frequency and sensor gain can be selected automatically with manual override capability.
This is the logic behind AutoTune: the scanner evaluates flame ON and flame OFF (background radiation present) and then selects sensor gain, bandpass frequency, and sensor range for optimum flame discrimination, and can also select suitable flame relay thresholds. In practical terms, AutoTune helps reduce the trial-and-error that often shows up during retrofit commissioning, especially on multi-burner furnaces where adjacent flames and reflected radiation are a constant problem.
Model Positioning: What “95DSS2-1” means
The InSight Type 95 model structure separates (1) sensor type, (2) feature level, and (3) mechanical/electrical configuration. The 95DSS2-1 is:
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95DS: Dual detector (IR & UV) scanner family
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S2: Expanded model with AutoTune, 21 frequency selections, 4 memory files, and communications
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-1: A standard configuration using a 12-pin electrical quick-disconnect style connection (non-“CG” style), consistent with Type 95 documentation that differentiates quick-disconnect models from “CG” captive-cable models
The scanner is specified with a maximum contact rating of 240 VAC for FM & UL models, which aligns with how the Type 95 documentation distinguishes 240 VAC maximum contact rating for FM/UL versions (and 50 VAC maximum for CE-approved versions).
Technical Specifications Summary (Type 95 / 95DSS2 Class)
| Parameter | FIREYE 95DSS2-1 / InSight Type 95 Expanded (S2) |
|---|---|
| Sensor Type | Dual sensor IR & UV (95DS family) |
| Feature Level | Expanded Model S2: AutoTune, 21 modulation frequencies, 4 memory files, communications |
| Power Supply | 24 VDC required; connection to 24 VAC or 120 VAC can damage the scanner |
| Flame Relay / Fault Relay | Flame relay SPST (N.O.); Fault relay SPST (N.C.) |
| Contact Rating | Min 10 mA @ 5 VDC; Max 2 A @ 30 VDC; 2 A @ 240 VAC (FM & UL models) |
| Analog Output | 4–20 mA flame strength output (referenced to 24 VDC common) |
| Enclosure | NEMA 4X, IP66 listed for Type 95 housings in model listing tables |
| Hazardous Location Orientation | Model listings include versions suitable for Class I Div. 2 / Class II Div. 2 environments depending on exact model/variant |
| Wiring / Interfaces (S2) | Remote file select (RFS1/RFS2) and communications conductors are designated for S2 models |
Integration Benefits for BMS and PLC-Based Systems
Because the 95DSS2-1 includes an internal flame relay and provides a 4–20 mA flame strength output, it can be used in multiple architectures:
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Classic flame-proving relay input: The internal flame relay provides a discrete “flame proven” signal to a burner management system or safety relay logic.
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Diagnostics and trending: The 4–20 mA output can be mapped into a PLC/DCS analog input for commissioning validation, long-term trending, and early warning of sighting degradation (dirty lens, alignment drift, fuel quality changes).
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Multi-condition parameter sets: With S2’s four memory files, you can store different optimized setpoints for different fuels or firing conditions, then switch between them using remote file selection wiring. This is directly described as a way to store different setpoints for different operating conditions (for example gas/oil, pilot/main, low fire/high fire).
This kind of structured “multi-file” setup can reduce nuisance trips when a burner transitions between regimes that have different flame brightness and flicker characteristics.
Commissioning Approach: What S2 AutoTune changes
In real plants, the hardest part of flame detection is not getting a signal—it is getting a signal that is stable, selective, and repeatable. The AutoTune function in S2 models is designed for that job: it scans the flame flicker frequency spectrum with flame ON and with flame OFF (background radiation present), then selects gain, bandpass frequency, sensor range, and can select flame relay thresholds for optimum discrimination.
For dual sensor models, Fireye notes that the flame relay and 4–20 mA output can operate on the sum of IR and UV signals, and commissioning can “favor” the sensor that shows the best flame ON/OFF ratio or stability. If needed, the scanner can be configured to use only IR or only UV.
After selecting sensor configuration and relay thresholds, Fireye emphasizes that proper flame detection and discrimination must be verified by cycling the burner and confirming the flame relay reliably de-energizes for all flame-out conditions, including with adjacent burners at different states and loads. This is a critical practical step for safety compliance and for avoiding “false flame” acceptance.
Practical Installation Notes (Power, Noise, and Wiring)
The Type 95 documentation includes a direct warning that the scanner requires 24 VDC and that applying 24 VAC or 120 VAC will damage the unit. It also recommends installation practices to reduce electrical noise and interference, including routing the scanner cable away from high-energy ignition wiring and high-inductive loads, and using conduit where appropriate.
For ordering ecosystem context, Fireye accessory documentation and third-party installation sheets list 95DSS2-1 as an Enhanced Model InSight scanner (dual detector) with quick disconnect, and associate it with typical mounting flanges and cable assemblies used across InSight installations.
Conclusion: Why choose FIREYE 95DSS2-1
The FIREYE 95DSS2-1 is a strong choice when you want an integrated dual IR/UV flame scanner that goes beyond basic proving and gives you commissioning leverage. Its Expanded S2 feature set (AutoTune, 21 frequency selections, 4 memory files, and communications capability) is designed for difficult combustion environments and multi-condition burners where manual tuning wastes time and increases risk.
For modern burner management systems, it delivers a practical combination of outputs and capabilities: internal flame relay for discrete interlocks, 4–20 mA for trending and diagnostics, and configuration flexibility for fuel switching and operating regime changes.
