Schneider Electric (Barber Colman) 2374-401 Relay

The Schneider Electric 2374-401 Air Motion Relay, formerly under the Barber Colman brand, is a critical pneumatic component engineered for precise HVAC air pressure sensing and airflow monitoring. Designed to function as a differential pressure switch, this device triggers a pneumatic signal based on the presence or absence of air velocity. It operates with a minimum 0.15" W.C. setpoint, making it sensitive enough to detect subtle changes in suction and discharge pressures within commercial ductwork or air handling units. This relay requires a supply pressure between 15 Psig and 30 Psig and maintains an efficient .49 SCIM air consumption rate. For field installation, the high and low ports are designed for 3/8" O.D. tubing, while the output signal utilizes 1/4" O.D. tubing. This pneumatic air motion relay is a standard solution for interlock circuits, ensuring that downstream equipment only operates when sufficient airflow is established.

Technical Specifications & Performance

• Precise Pressure Detection: Actuates at a differential pressure as low as 0.15" W.C. to ensure reliable system interlocking.
• Versatile Port Configuration: Features 3/8" O.D. connections for sensing ports and 1/4" O.D. for signal integration.
• Low Air Consumption: Engineered for efficiency with a .49 SCIM air use rating to minimize load on the pneumatic master controller.
• Robust Pressure Range: Compatible with standard pneumatic control systems operating between 15 and 30 Psig.
• Field-Proven Reliability: The Barber Colman 2374-401 legacy design ensures seamless integration into existing pneumatic logic loops.

Common Installation Questions

How do I plumb the 2374-401 for suction pressure sensing?
Connect the low-pressure port to the suction side of the fan using 3/8" O.D. tubing. Ensure the high-pressure port is vented to the atmosphere or a reference point to accurately measure the static pressure drop.

What is the maximum supply pressure for this relay?
The unit is designed for a standard pneumatic range; do not exceed 30 Psig to prevent damage to the internal diaphragm and ensure consistent pneumatic signal delivery.

Can this relay be used to prove fan operation?
Yes, this is a primary application for HVAC airflow verification. By sensing the differential across the fan, the relay provides the necessary pneumatic logic to enable heating or cooling stages.

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.