System Sensor 4W-B Smoke Detector 4-Wire

System Sensor 4W-B — conventional 4-wire i3 series photoelectric smoke detector, supplied as a plug-in head with its mounting base included. The 4W-B is the photoelectric-only 4-wire model; it has no thermal sensor and no freeze trouble signal.

A 4-wire detector takes operating power from a separate supervised power circuit and reports alarm through dry contacts, so the panel sees a contact closure rather than a change in loop current. That keeps detector power independent of the initiating circuit and makes the 4W-B a common choice where a security or combination panel supplies auxiliary power. Its own alarm draw is modest — 20 mA at 12 V, 23 mA at 24 V — and standby is 50 µA. The plug-in design lets the base be pre-wired and mounted during rough-in, with the head fitted later by a Stop-Drop ’N Lock action. Drift compensation and smoothing algorithms adjust for gradual chamber contamination and reject short-term interference, and wide-angle dual-color LEDs show power up, standby, out-of-sensitivity and alarm. Sensitivity is read in percent-per-foot obscuration with the SENS-RDR. Head and mounting base ship together.