The S4-720 carries a thermal element and nothing else, reporting on channel 2 alone. That suits kitchens, plant rooms and loading bays — places where a smoke chamber spends its life answering cooking fumes, exhaust or dust.
With no chamber, there is nothing for aerosols to settle in, which is the practical reason this variant survives environments that defeat smoke heads. Two channels showing where you expect a heat sensor means a different device was fitted.
Technical data
| Label marking | H |
| Sensing | Heat only |
| Analogue channels | 2 |
| Standards | EN 54-5:2000 A1:2002 |
| Baffle ring | Black (silent) |
Specifications from 4188-1073 issue 3.
Compatibility
Replaces a smoke variant on an existing S4-700 without rewiring. Where the location also needs an audible output, S4-780-S is the heat variant with a sounder built in.
Installation
A plain base fixing. Where visible proof is wanted the device is alive, its red fire LED can be configured to flash periodically as in-operation confirmation.
Full details: S-Quad heat sensor — installation data — 4188-1073 issue 3 · 28 pages · heat entry, channel 2 assignment, EN 54-5 approval row
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