Detectors

Duct Smoke Detectors

The D4120 is the 4-wire photoelectric duct smoke detector for standard air handling units: 100 to 4,000 fpm airflow, 4 F to 158 F, 0 to 95 percent humidity, with a plug-in sensor head for cleaning and replacement and interconnection of up to 50 units so every detector on a system switches its relays while only the one sensing smoke goes into alarm. Its power board can monitor a second D4S sensor at the same time, covering supply and return sides from one housing, and the D4P120 power board and D4S sensor are available separately as replacement components.

The D4120W adds a NEMA 4 watertight housing for rooftop units and other harsh locations, and the D2 provides the same sensing on a 2-wire initiating circuit with trouble and maintenance signaling and a cover tamper. For no-flow and low-flow air handling equipment, the 2D51 low-profile photoelectric head with a B210LP base and D4P120 power board is listed to UL 268A specifically for that use.

Sampling tubes, relays, and test stations are under accessories and multi-voltage relays. Browse the full System Sensor catalog, or contact our team to match a detector to your duct size and panel.

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