Replacing a System Sensor smoke detector should be straightforward — but with several detector series and multiple base options, it’s easy to end up with an incompatible combination. This guide covers the most commonly replaced System Sensor smoke detectors (2W-B, 4W-B, and i3 series) and explains how to match them with the correct detector base (B200S, B200SR, B210LP).
Smoke Detector Series Overview
2W-B — 2-Wire Photoelectric Smoke Detector
The 2W-B is System Sensor’s standard 2-wire photoelectric smoke detector for conventional fire alarm systems. It connects directly into the detection zone circuit and draws power from the panel’s detection loop. The 2W-B is designed to be compatible with a wide range of conventional fire alarm control panels and is one of the most widely deployed detectors in commercial buildings.
Typical applications: Office buildings, schools, hotels, healthcare facilities on conventional fire alarm systems. Best used on 12V or 24V 2-wire zone circuits.
4W-B — 4-Wire Photoelectric Smoke Detector
The 4W-B (and related 4WTA-B, 4WTAB) uses separate power and alarm wiring (4-wire configuration), providing a supervised alarm output relay. This design is required in many retrofits where older relay-based detection circuits are in use, and for applications requiring a dry contact output for elevator recall, door release, or HVAC shutdown.
Typical applications: Elevator lobbies, HVAC control, door release interfaces, older conventional systems with relay-based initiating circuits.
i3 Series — Intelligent Multi-Criteria Detectors
The i3 Series represents System Sensor’s advanced addressable detector line. i3 detectors combine photoelectric smoke sensing with thermal detection and use proprietary algorithms to reduce nuisance alarms. Each detector has a unique address on the SLC (signaling line circuit) loop, allowing the fire alarm panel to identify exactly which device activated.
Typical applications: Addressable fire alarm systems (Notifier, Simplex, Gamewell-FCI, Siemens, etc.) requiring exact device location reporting. The i3 series is the preferred replacement for any addressable System Sensor smoke detector in intelligent systems.
Detector Base Selection
System Sensor smoke detectors separate from their bases, making it easy to swap a detector head without rewiring. However, not all bases are compatible with all detectors — selecting the right base is essential.
B200S — Standard Detector Base
The B200S is the standard 4″ mounting base for i3 Series and compatible System Sensor detectors. It mounts to a standard electrical box (4″ round, octagonal, or square with adapter) and uses a plug-in locking connector. Compatible with i3 series heads. Not suitable for bases requiring relay or sounder functionality.
B200SR — Relay Base
The B200SR includes a built-in relay that activates when the detector alarms. Use this base when you need a dry contact output from the detector for local HVAC shutdown, elevator recall, or door release without requiring a separate module. Compatible with i3 series intelligent detectors. The relay is supervised and programmable on addressable systems.
B210LP — Low-Profile Base
The B210LP is a low-profile version of the standard base, measuring only 0.59″ in height. Use this base in applications where ceiling aesthetics are a concern — hotel rooms, executive offices, or any space where a minimal profile is desired. Functionally equivalent to the B200S but with a slimmer form factor.
Wiring Overview
For 2W-B detectors: Connect the two zone circuit wires to the base terminals. The detector installs by rotating into the base (bayonet lock). Always test the detector after installation using the test magnet or System Sensor RTS151 remote test station.
For 4W-B detectors: Connect power wires (typically red/black for 12V or 24V) to power terminals, and alarm output wires to the relay terminals. Verify polarity before applying power.
For i3 Series with B200S/B200SR/B210LP: Connect the SLC loop wires to the base terminals. The detector head plugs into the base and locks with a quarter-turn. Address the detector per your panel’s instructions before installing the head.
Order Your System Sensor Replacement Parts
Life Safety Consultants stocks the full range of System Sensor smoke detectors and compatible bases for same-day shipping. Browse our complete System Sensor replacement parts catalog or call us at 1-888-557-0558 to confirm compatibility with your specific fire alarm panel and existing base model.
