System Sensor 4WTR-B 4-wire Smoke Detector and Heat Sensor w/ Relay

The System Sensor 4WTR-B is an i3 Series conventional 4-wire photoelectric smoke detector with a built-in 135°F fixed heat sensor and a Form C relay for local control or signaling. It includes the plug-in base and uses drift compensation, smoothing algorithms, and dual-color LED status to help reduce nuisance alarms and speed up inspection. Key Specifications: Type: Conventional 4-wire photoelectric smoke and heat detector with Form C relay Core Function(s): Photoelectric smoke detection with fixed 135°F thermal sensing and onboard Form C relay output for auxiliary control/monitoring Loop/Protocol: Conventional 4-wire Power: 10 to 35 V (4-wire), non-polarized; 50 µA max average standby; 35 mA max alarm current Indicators/UI: Dual-color LEDs for power-up, standby, out-of-sensitivity, freeze trouble, and alarm status; simplified sensitivity measurement with optional reader Compatible Accessories: SENS-RDR – Sensitivity reader (percent-per-foot obscuration display) A77-AB2 – Retrofit adapter bracket System Compatibility: Works with conventional fire alarm control panels that support 4-wire smoke detectors and applications using a Form C relay interface.