System Sensor D4120 Detector

The System Sensor D4120 is an industrial-grade 4-wire photoelectric duct smoke detector designed for high-performance smoke detection in HVAC air handling systems. This InnovairFlex duct smoke detector operates across a wide air velocity range of 100 to 4,000 feet per minute, making it suitable for both low-flow and high-volume applications. It features a versatile pivoting housing that accommodates square or rectangular footprints and mounts easily to round or rectangular ductwork. Engineered with a photoelectric sensor head, the unit provides superior false alarm immunity and simplified maintenance via its plug-in design. The D4120 duct smoke detector is a direct replacement for legacy models 70-540000-002, 70-600000-054, and 70-600000-157, as well as the DH100ACDCLP. Equipped with two DPDT relay contacts and a dual 24Vac/dc or 120Vac power supply, this detector supports multi-fan shutdown through a patented interconnect feature that allows for up to 50 synchronized units. Its tool-free sampling tube installation and improved 3/4-inch conduit knockout ensure a streamlined HVAC duct smoke detector installation for field contractors.

Key Benefits

• Multi-Voltage Compatibility: Operates on 24V AC/DC or 120V AC, providing flexibility for various control circuit requirements.
• Broad Environmental Range: Performance-tested for temperatures from -4°F to 158°F and 0% to 95% non-condensing humidity.
• Advanced Interconnect Logic: Supports interconnection of up to 50 detectors for comprehensive system shutdown upon smoke detection.
• Streamlined Maintenance: Features a front-accessible Test/Reset button and a plug-in sensor head that can be serviced without removing the entire housing.
• Short Circuit Protection: Built-in safeguards protect internal components from operator wiring errors during commissioning.

Common Questions

• How do I wire the D4120 for fan shutdown? Use the DPDT Form-C auxiliary relay contacts to break the starter or control circuit of the air handler. Ensure polarity is maintained if using the interconnect feature for multiple fans.
• Do I need a specific sampling tube for my duct width? Yes, the sampling tube must be ordered separately based on the duct's width to ensure the sensor receives adequate airflow for accurate detection.
• Can I use a secondary sensor with this power board? The D4120 features 2:1 sensor-to-power capability, allowing the master power board to monitor a second sensor (Model D4S) for supply and return side coverage.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.