System Sensor ST-5 Sampling Tube

The System Sensor ST-5 is a 5-foot metal sampling tube engineered for high-performance smoke detection in HVAC ducts ranging from 4 to 8 feet in width. Built with a durable rigid steel construction, this tube is essential for contractors installing or maintaining duct smoke detectors in commercial and industrial air handling systems. The ST-5 acts as the direct replacement for L-313-1, ensuring seamless integration into legacy systems without the need for extensive field modifications.

For a precise HVAC duct smoke detector installation, the ST-5 utilizes a series of factory-drilled air inlet holes to draw a representative cross-sectional sample of airflow into the detector’s sensing chamber. Technicians must ensure the air inlet holes face directly into the airflow for maximum sensitivity. Following standard NFPA guidelines, this 5-foot tube allows for 2/3 duct coverage in larger air handlers, and because it exceeds 3 feet in length, it requires end-support on the opposite side of the duct to maintain structural integrity under high air velocities up to 4,000 FPM. This component is compatible with the System Sensor Innovair, DNR, and legacy DH100/DH400 series housings.

• Universal Compatibility: Works with System Sensor InnovairFlex, DH400ACDCIHT, and DNR duct detectors.
• Direct Retrofit: Functions as the official L-313-1 cross-reference for simplified maintenance.
• Enhanced Sampling: Provides critical low-flow performance for ducts up to 8 feet wide.
• Rugged Durability: Metal construction prevents sagging or bending in high-velocity HVAC environments.
• Ease of Installation: Features a secure locking tab for quick front or rear mounting into duct housing bypass ports.

Is the ST-5 compatible with Honeywell or Fire-Lite duct detectors?
Yes, as these brands typically utilize System Sensor OEM sampling tubes. Always verify the detector model, but if it accepts Innovair series accessories, the ST-5 is the standard fit for 5-foot requirements.

Can the ST-5 be cut to length?
Technicians often cut these tubes in the field to match specific duct dimensions. Always ensure the sampling tube end cap is reinstalled after cutting to maintain the proper air pressure differential and flow into the sensor.

How do I confirm the orientation?
The holes must face the supply air direction. Failure to orient the holes toward the incoming airflow will result in a "No Flow" condition on the detector or a failure to trip during a smoke detector manometer test.

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.