System Sensor D4120W 4-Wire Weatherproof Duct Smoke Detector – Photoelectric Low-Flow Air Duct Detector

The System Sensor D4120W is a 4-wire weatherproof photoelectric duct smoke detector designed to provide reliable smoke detection in HVAC duct systems operating in outdoor, humid, or harsh environmental conditions. Featuring advanced low-flow air sampling technology, the D4120W delivers dependable smoke detection across a wide air velocity range, making it suitable for protecting air handling units and preventing the spread of smoke through ventilation systems.

Housed in a durable weatherproof enclosure, the D4120W is engineered to withstand demanding environments while maintaining reliable performance. The detector is suitable for air velocities from 100 to 4,000 ft/min (0.5 to 20.3 m/s), allowing installation in a broad range of commercial and industrial HVAC applications.

The detector supports multiple power options, including 20–29 VDC, 24 VAC (50/60 Hz), and 120 VAC (50/60 Hz), providing installation flexibility for a variety of system designs. Two DPDT Form C relay outputs (Alarm and Trouble) enable straightforward integration with compatible fire alarm and building management systems.

Designed to comply with UL 268A requirements for smoke detectors used in air handling systems, the D4120W is an ideal solution for protecting ductwork in commercial buildings, industrial facilities, healthcare environments, educational campuses, and other critical infrastructure.

Key Features:

• 4-wire photoelectric duct smoke detector
• Weatherproof enclosure for outdoor and harsh environments
• Advanced low-flow air sampling technology
• Air velocity range of 100–4,000 ft/min (0.5–20.3 m/s)
• Multiple power options: 20–29 VDC, 24 VAC, or 120 VAC
• Two DPDT Form C relay outputs (Alarm and Trouble)
• Suitable for commercial and industrial HVAC systems
• Designed for smoke detection within air handling ducts
• Complies with UL 268A for duct smoke detection

 

Typical Applications:

• Commercial office buildings
• Hospitals and healthcare facilities
• Shopping centres
• Schools and universities
• Industrial plants
• Warehouses and distribution centres
• HVAC air handling units
• Outdoor or harsh environmental duct installations

The System Sensor D4120W Weatherproof Duct Smoke Detector provides dependable photoelectric smoke detection for HVAC systems in demanding environments, combining low-flow sensing technology, flexible power options, and robust weatherproof construction to help protect buildings from the spread of smoke through ventilation systems.