Honeywell Self-Test Detectors: Gent S4T and Notifier NFSTI Explained
Short answer: Honeywell Self-Test detectors test themselves. At the tap of a button in the CLSS app, each detector heats its own heat sensor and releases a small puff of real smoke into its chamber, proving it can detect a fire. No ladders, no smoke poles, no disruption to the building. The technology is available on both Gent (S-Quad S4T range) and Notifier (NFSTI range) systems – the part numbers differ, but the principle is the same.
Self-Test is a Honeywell technology, developed across its Gent and Notifier fire detection brands.
Why detector testing needs a rethink
Every fire alarm system needs regular testing and inspection to stay compliant and, more importantly, to keep people safe. But testing detectors the traditional way is slow. Honeywell estimates that manually testing smoke detectors accounts for around 70–80% of the time spent inspecting a typical fire detection system.
It's also disruptive. Engineers need ladders and poles, access to every room, and often have to work evenings or weekends so they don't disturb occupants. And some detectors are simply hard to reach – in high ceilings, voids or restricted areas – so they don't always get tested as thoroughly as they should.
There's a safety risk too. Detectors can be left covered after building work, sometimes for years, and a quick visual check from the floor won't always catch it.
How Self-Test works
Each Self-Test detector has a tiny smoke generator and heater built in. When a test is triggered from the CLSS app:
- The detector releases a small amount of real smoke into its optical chamber and gently heats its heat sensor – a genuine functional test, not a simulated one.
- A small fan then blows the smoke out through the detector's smoke entry points, proving they aren't blocked or covered.
- The result is recorded automatically and added to a digital compliance report.
Each detector is only out of action for around a minute during its test, and the rest of the system stays live throughout. If a real fire is detected elsewhere, testing stops and the system responds as normal.
Every detector also has a built-in Bluetooth beacon. When the engineer walks the building with the CLSS app, it picks up nearby detectors, shows their details, and records that the engineer was within visual inspection range – so the visual check is proven, not just ticked off.
The benefits
For building owners and facilities managers
- Far less disruption – no ladders in offices, classrooms, wards or bedrooms. Testing can happen during normal working hours.
- Every detector tested – hard-to-reach devices are tested just as easily as the rest, so 100% functional testing is achievable.
- Proof of compliance – digital reports show exactly which devices were tested, how, and when. Ideal for audits, insurers and fire authority visits.
- Blocked or covered detectors found – the smoke has to pass through the entry points, so a covered detector will show up.
For installers and maintenance contractors
- Big time savings – in a Honeywell-witnessed case study at a London school with 426 detectors, Self-Test cut the man-hours needed for testing by 86%.
- Fewer site visits – that same case study estimated 3,490 kg of CO₂ avoided over the system's life (a 69% reduction versus manual testing), mostly from fewer van journeys.
- A lighter toolkit – a phone or tablet replaces smoke poles, heat poles, aerosol cans and ladders.
- No over-spraying – no risk of too much test aerosol leaving a detector in pre-alarm.
- Fast, flexible testing – test a single device, a zone, a loop or a whole panel. On Gent systems, up to six devices per loop can be tested at once, across any number of loops.
- Tidy up as you go – correct inaccurate device labels and loop mapping from the app.
Worth knowing: a magnet test or software-only check doesn't count as a functional smoke test under most codes of practice. Self-Test introduces real smoke and heat, so it does.
Gent and Notifier Self-Test part numbers
The technology is shared, but each brand has its own range for its own panels. Use the one that matches your system.
Gent S-Quad Self-Test (S4T)
The S4T range brings Self-Test to Gent's S-Quad family, with sounder, voice and VAD versions so one device can detect, test itself and raise the alarm. Self-Test works on Gent Vigilon and Compact Plus panels.
| Part number | Description |
|---|---|
| S4T-720 | Self-Test heat sensor |
| S4T-710 | Self-Test optical heat sensor |
| S4T-711 | Self-Test dual optical heat sensor |
| S4T-780-S | Self-Test heat sensor with sounder |
| S4T-770-S | Self-Test optical heat sensor with sounder |
| S4T-771-S | Self-Test dual optical heat sensor with sounder |
| S4T-711-V | Self-Test dual optical heat sensor with voice sounder |
| S4T-711-VAD-HPR | Self-Test dual optical heat sensor with high-power red VAD |
| S4T-720-V-VAD-HPR | Self-Test heat sensor with voice sounder and high-power red VAD |
| S4T-711-V-VAD-HPR | Self-Test dual optical heat sensor with voice sounder and high-power red VAD |
| S4TB-711-V-VAD-HPR | Black Self-Test dual optical heat sensor with voice sounder and high-power red VAD |
Associated products
| Part number | Description |
|---|---|
| S4-700 | Base for all Self-Test sensors |
| S4BK-700 | Black base for black Self-Test sensors |
| S4-705 / S4BK-705 | IP21C plate (white / black) |
See the full range on Honeywell's Gent Self-Test page or download the Gent S-Quad Self-Test datasheet (PDF).
Notifier Self-Test (NFSTI)
Notifier's NFSTI range brings the same technology to Notifier systems, with Self-Test running on the Notifier INSPIRE panel. The detectors fit the existing B501AP base, so upgrading doesn't mean replacing bases.
| Part number | Description |
|---|---|
| NFSTI-OPT | Self-Test optical smoke detector with isolator |
| NFSTI-SMT2 | Self-Test optical-heat multi-sensor with isolator |
| NFSTI-THE | Self-Test programmable heat detector (fixed or rate-of-rise) with isolator |
Accessories
| Part number | Description |
|---|---|
| B501AP | Mounting base, pure white |
Find out more on Honeywell's Notifier Self-Test page or download the Notifier NFSTI Self-Test datasheet (PDF).
What you need to get started
- A compatible panel – Gent Vigilon or Compact Plus, or Notifier INSPIRE
- Current EN54 loop cards (not legacy cards), with up-to-date firmware
- A CLSS gateway (one per network) and the CLSS mobile app
- Self-Test detectors in place of the standard heads you want to test automatically
Not sure whether your system is ready? Send us the panel model and we'll check it for you.
Frequently asked questions
Is Self-Test a real functional test?
Yes. The detector generates real smoke and real heat inside itself, then clears the smoke out through its entry points. It's EN54 approved, and Honeywell states it meets BS 5839-1 functional testing requirements.
Do Self-Test detectors still need a visual inspection?
Yes, but it's quicker and provable. The built-in Bluetooth beacon lets the CLSS app confirm the engineer was within visual inspection range of each device.
How many times can a detector self-test?
They're designed for up to four functional tests a year over the life of the detector. CLSS tracks how many tests each device has used.
Is the fire alarm offline during testing?
No. Each detector is only out of action for around a minute while it tests, and the rest of the system stays live. A real fire elsewhere stops the test and triggers the system as normal.
Can I use Gent Self-Test detectors on a Notifier panel, or vice versa?
No. Gent S4T detectors work on Gent panels and Notifier NFSTI detectors work on Notifier panels. The technology is the same, but the part numbers and protocols are different.
Can I mix Self-Test and standard detectors on the same system?
Yes. Many sites start with Self-Test detectors in hard-to-reach or sensitive areas and upgrade the rest over time. Tell us your panel and loop details and we'll help you plan it.
Thinking about Self-Test? Talk to us
Self-Test is a specialist upgrade that depends on your panel, loop cards and CLSS setup, so it isn't sold through our online shop. Whether you're planning a new Gent or Notifier installation, upgrading an existing system, or just want to know whether Self-Test makes sense for a site, we're happy to talk it through.
Call 020 8861 2466, email sales@firealarmwarehouse.co.uk or use our contact form. Send us your panel model and a rough device count and we'll come back to you.
For everyday parts, browse our Gent fire alarm parts and Notifier fire alarm parts, or read why genuine parts matter.