System Sensor D4120 InnovairFlex 4-Wire Photoelectric Duct Smoke Detector – Low-Flow Air Sampling Detector

The System Sensor D4120 InnovairFlex is a 4-wire photoelectric duct smoke detector designed to provide reliable smoke detection within HVAC air handling systems. Featuring advanced low-flow air sampling technology and a plug-in photoelectric sensor head, the D4120 delivers dependable performance while simplifying installation, testing, and maintenance.

The InnovairFlex housing incorporates a unique pivoting design that allows the detector to mount on both round and rectangular ductwork, providing installation flexibility across a wide range of HVAC configurations. The detector operates effectively in challenging conditions, supporting airflow speeds from 100 to 4,000 ft/min (0.5 to 20.3 m/s), temperatures from -20°C to +70°C, and humidity levels up to 95% RH non-condensing.

Designed for efficient system integration, the D4120 includes two DPDT Form C relays for alarm and trouble signalling and supports interconnection of up to 50 InnovairFlex detectors. When multiple units are interconnected, all detector relays can activate during an alarm condition while only the detector sensing smoke identifies the source, helping simplify fire location identification.

The detector features a spacious wiring compartment, high-contrast terminal markings, built-in short-circuit protection, accessible Test/Reset functionality, and configurable DIP switch settings for installation flexibility. With support for optional accessories and compatibility with previous Innovair models, the D4120 provides a dependable solution for commercial and industrial HVAC smoke detection applications.

Key Features:

• 4-wire photoelectric duct smoke detector
• InnovairFlex low-flow air sampling technology
• Plug-in photoelectric sensor head for easy servicing
• Pivoting housing suitable for round and rectangular ductwork
• Air velocity range: 100–4,000 ft/min (0.5–20.3 m/s)
• Two DPDT Form C relays for alarm and trouble indication
• Supports interconnection of up to 50 detectors
• Built-in short-circuit protection
• Large wiring compartment with high-contrast terminals
• Cover-mounted Test/Reset button
• Field-selectable DIP switch configuration
• Compatible with remote test accessories

Typical Applications:

• Commercial office buildings
• Shopping centres
• Hospitals and healthcare facilities
• Schools and universities
• Industrial facilities
• Warehouses
• HVAC air handling systems
• Building smoke control applications