Schneider Electric (Barber Colman) MK-4421 Actuator

The Schneider Electric (Barber Colman) MK-4421 is a heavy-duty pneumatic damper actuator engineered for proportional or two-position control in demanding HVACR applications. This spring return actuator is the designated direct replacement for M593-5095 and M693-5095 models, ensuring seamless integration into existing Barber Colman pneumatic control systems. Featuring a rugged cast aluminum housing and a durable neoprene diaphragm, the MK-4421 provides a significant 11 sq. in. effective area, delivering consistent force across an 8 to 13 psi spring range.

Designed for professional contractors, this unit offers an adjustable stroke from 1/2" to 3", factory-set at 2" to simplify standard installations. The 1/8" FNPT air connections and standard 30 psig maximum safe air pressure rating make it a reliable choice for air valves and damper assemblies. Its versatile mounting capability allows for installation in any orientation, while the sintered bronze shaft-guide bushings maintain precise alignment even in high-cycle environments ranging from -20 to 160°F.

• Universal Compatibility: Serves as the direct OEM 1-to-1 replacement for obsolete M593-5095 and M693-5095 actuators.
• Field Adjustability: Adjustable starting pressure and 1/2" to 3" stroke range permit fine-tuning for specific damper degrees.
• Robust Construction: Die-cast aluminum body and beaded molded neoprene diaphragm prevent air leaks and resist environmental degradation.
• High Torque Output: The 11 sq. in. effective area ensures sufficient force to drive both parallel and opposed blade dampers.

Is the MK-4421 compatible with older Barber Colman linkage kits?
Yes, the MK-4421 is designed to interface with standard Barber Colman accessories, including AM-111, AM-112, and AM-113 crank arms, as well as the AM-743 linkage kit for M-693 series replacements.

What is the maximum operating pressure for this pneumatic actuator?
While the standard control range is 8 to 13 psi, the unit has a maximum safe air pressure rating of 30 psig. For optimal proportional control, at least 15 psi should be available to the actuator.

Can the diaphragm be replaced in the field?
Yes, the MK-4421 is designed for easy maintenance. The internal neoprene diaphragm can be replaced by removing the top power housing screws without removing the entire assembly from the bracket.

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.