Schneider Electric (Barber Colman) MK-3121 Actuator

Optimize your pneumatic control systems with the Schneider Electric MK-3121 Actuator, a precision-engineered proportional pneumatic damper actuator designed for the professional HVACR contractor. This rugged unit features a 8 to 13 PSI spring range and a versatile 2 to 4 inch adjustable stroke, allowing for exact field calibration in air handling units, mixing boxes, and VAV systems. The MK-3121 is the primary direct replacement for legacy models MK-3121-110, MK-3121-115, and MK-3221, ensuring a seamless drop-in fit for retrofit applications. Built with a die-cast aluminum housing and a durable rolling neoprene diaphragm, it provides consistent linear force with an 8 square inch effective area. The internal spring return mechanism ensures the actuator shaft retracts safely upon the loss of control air pressure, protecting your system components. With a 30 PSIG maximum air pressure rating and 1/8" FNPT air connections, this actuator is a staple for reliable airside equipment modulation.

• Universal Compatibility: Serves as the standard Schneider Electric MK-3121 replacement for Barber Colman pneumatic systems, simplifies inventory for service technicians.
• Precise Control: The adjustable stroke damper actuator design allows for onsite tuning to match specific damper linkage requirements from 2 to 4 inches.
• Fail-Safe Operation: Mechanical spring return ensures immediate shaft retraction to the "home" position if system pressure fails.
• Industrial Durability: Features a rugged cast aluminum body and a long-lasting beaded molded neoprene diaphragm for extended service life in high-cycle environments.
• Standard Fitting: Equipped with a 1/8 inch FNPT connection for easy integration with standard pneumatic tubing and fittings.

Is the MK-3121 compatible with older Barber Colman installations?
Yes, the Schneider Electric MK-3121 is a direct replacement for Barber Colman MK-3121-110 and MK-3121-115. It shares the same mounting footprint and technical specifications, making it an ideal choice for maintaining legacy pneumatic systems.

Can the internal diaphragm be replaced if it fails?
Technicians can service this unit in the field using the PND-2-1 replacement diaphragm, which is compatible with the entire MK-3000 series housing.

What is the maximum operating pressure for this unit?
The MK-3121 is rated for a maximum air pressure of 30 PSIG, though it typically operates within the 8 to 13 PSI control range for standard proportional modulation.

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.