SYSTEM SENSOR Duct Smoke Detector: 120V AC/24V AC/DC Volt, Sound Alert, Duct Mount
The SYSTEM SENSOR D4120 is a duct-mount smoke detector for fire alarm systems, featuring a photoelectric sensor and sound alert. It operates on 24V AC/DC or 120V AC with a current rating of 25 mA @ 24V DC, is…
SKU 3G-OTH-546835
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Product Description
The SYSTEM SENSOR D4120 is a duct-mount smoke detector for fire alarm systems, featuring a photoelectric sensor and sound alert. It operates on 24V AC/DC or 120V AC with a current rating of 25 mA @ 24V DC, is FM-approved, and has a 5-inch overall height. 3G Electric interprets your demand for this hardwired, rectangular detector and delivers it with specialist support across 14 industrial departments.
Frequently Asked Questions
What is the SYSTEM SENSOR D4120 duct smoke detector used for?
The SYSTEM SENSOR D4120 is a duct-mount smoke detector designed for fire alarm systems in commercial HVAC applications. It uses a photoelectric sensor to detect smoke in air ducts and provides a sound alert, helping to prevent smoke recirculation through ventilation systems.
What are the specifications of the SYSTEM SENSOR D4120?
The D4120 operates on 24V AC/DC or 120V AC with a current rating of 25 mA @ 24V DC. It is FM-approved, hardwired, and has a rectangular shape with a 5-inch overall height. The sensor type is photoelectric, and it mounts directly in the duct.
Where to buy the SYSTEM SENSOR D4120 worldwide?
3G Electric supplies the SYSTEM SENSOR D4120 duct smoke detector worldwide. As a global industrial solutions provider, we handle full logistics, customs clearance, and delivery to your facility. Contact us to source this FM-approved detector for your fire alarm system.
How to install the SYSTEM SENSOR D4120 duct smoke detector?
Install the D4120 in the duct with the airflow arrow pointing downstream. Wire per the manufacturer's diagram for 24V AC/DC or 120V AC. Ensure proper clearance for the 5-inch height and test the sound alert after installation. Always follow local fire codes and the SYSTEM SENSOR manual.
SYSTEM SENSOR Products
3G Electric supplies SYSTEM SENSOR smoke detectors for fire alarm systems. We supply genuine products with in-stock availability on common SKUs, technical documentation, commissioning support, and warranty service — worldwide.




