Description
Honeywell Gent S4-771-S Dual Optical Heat Sensor Sounder | BS 5839-1:2025
Introduction
The Honeywell Gent S4-771-S is a dual optical heat sensor sounder designed for areas where a standard smoke detector may be too sensitive on its own, but where you still need fast, intelligent fire detection and local alarm signalling. As part of the Gent Vigilon S-Quad range, it combines dual optical sensing, heat detection, an integral sounder, and a built-in short-circuit isolator in one loop-powered device, helping reduce extra wiring and hardware on site.
At a Glance
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Product code: S4-771-S
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Device type: Dual optical heat multi-sensor with integral sounder
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System compatibility: Gent Vigilon fire alarm systems
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Built-in features: Integral sounder and short-circuit isolator
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Best for: Commercial environments needing multi-sensor detection with local audible warning
Technical Specifications
| Feature | Specification |
|---|---|
| Product Code | S4-771-S |
| Detection Type | Analogue Addressable Dual Optical Heat Multisensor With Sounder |
| Device Load Factor | 1 |
| Sounder Output | 90 dB(A) @ 1m (Standard Setting) |
| Operating Voltage | 35V to 41V |
| IP Rating | IP31 (Enhanced Indoor Protection) |
| Compliance | EN54-7, EN54-17, BS 5839-1:2025 |
| Dimensions | 117mm (D) x 49.6mm (H) |
| Weight | 110g (Head only) / 170g (with S4-700 base) |
System Design & Loop Loading
When planning a Gent Vigilon or Compact system, the S4-715 is highly efficient due to its low power requirements. Use the following data for your loop calculations:
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Max Devices Per Loop: The Gent Vigilon system supports a maximum of 200 addressable devices per loop.
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Loading Capacity: With a Device Load Factor of 1, you can theoretically populate a full 200-device loop with S4-715 sensors without exceeding the loop power threshold (typically 800mA on modern EN54 loop cards).
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Power Optimization: Because this unit draws minimal current compared to sensor-sounder-VAD variants (which can have load factors of 3 to 13), it is the ideal choice for high-density areas where loop length and voltage drop are a concern.
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Mixed Loops: Note that if your system includes high-draw devices like the S4-711-VAD, the total load must be summed to ensure it remains within the panel's specific loop card capacity.
System Compatibility & Required Accessories
The S4-771-S is designed for use on Honeywell Gent Vigilon systems and requires the S4-700 common base for installation. Because it combines detection and audible warning in a single addressable unit, it is a strong option where you want to simplify loop device layouts without adding separate sounder points unnecessarily.
How It Works Within a Vigilon System
Within a Gent Vigilon loop, the S4-771-S operates as an addressable multi-sensor device that communicates directly with the panel, allowing the system to identify both the detector location and alarm condition accurately. Its combination of dual optical scatter technology and heat sensing helps the panel make better fire decisions in more complex environments, while the integral sounder provides local audible warning from the same field device.
Key Benefits & Technology
The main strength of the Gent S4-771-S is that it combines multiple functions in one device: dual optical sensing, heat detection, sounder output, and short-circuit isolation. Honeywell describes the S-Quad range as using advanced sensing combinations to improve detection performance, and reseller technical summaries highlight the unit’s ability to help filter out challenging conditions such as steam and dust, reducing nuisance alarms compared with simpler detectors.
Key benefits
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Multi-sensor detection for improved decision making
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Integral sounder for local alarm notification
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Built-in short-circuit isolator for loop protection
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Suitable for addressable Gent Vigilon installations
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Can reduce the need for separate detection and sounder devices on site
Typical Applications
The S4-771-S is well suited to commercial buildings where you want the benefits of a gent optical heat multisensor together with an on-board sounder. Typical applications include:
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Hotels
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Offices
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Schools
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Care environments
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Corridors and shared commercial spaces requiring local alarm signalling
Installation & Maintenance
Installation should be carried out on the correct S4-700 base and commissioned in line with the requirements of the relevant Gent panel configuration.
Ongoing inspection, testing, and maintenance should follow BS 5839-1, with routine service intervals appropriate to the site risk and system design. Because this is a combined detector and sounder device, installers should also verify sounder operation during periodic testing, not just detector response.
Comparison: S4-771-S vs S4-770-S
| Model | Main Sensing Type | Sounder | Best Use |
|---|---|---|---|
| S4-771-S | Dual Optical + Heat | Yes | Sites wanting higher immunity and multi-sensor decision making |
| S4-770-S | Optical + Heat | Yes | Sites wanting a simpler optical heat sensor sounder option |
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