Schneider Electric (Barber Colman) MK-4641 Proportional Control

The Schneider Electric (Barber Colman) MK-4641 is a job-ready pneumatic valve actuator engineered for precise proportional control and reliable performance in commercial HVAC applications. Featuring an 11-square-inch effective diaphragm area, this unit is built for linear movement and is the standard choice for managing VB-7000 series globe valves, as well as legacy VB-9000, VB-314, and VB-131 models. Its 3-13 PSI pneumatic spring range allows for consistent modulation of hot and chilled water valves, ensuring your system maintains accurate temperature and pressure setpoints.

Constructed with a rugged die-cast aluminum housing and a NEMA 1 enclosure, the MK-4641 is designed to thrive in demanding mechanical rooms. This spring return valve actuator utilizes a resilient neoprene diaphragm that is easily replaceable, facilitating straightforward field maintenance. The 1/2-inch nominal stroke and 1/8-inch NPT air connection mean this actuator integrates seamlessly into established pneumatic control systems without hardware modifications. Whether you are performing a retrofit or a new installation, the MK-4641 delivers the high-torque, failure-safe proportional movement professional contractors require.

• Broad Compatibility: Native support for TAC VB-7xxx series valves and discontinued legacy models from 1/2" to 1-1/4" sizes.
• Fail-Safe Logic: Mechanical spring return ensures the output shaft retracts automatically upon loss of pilot air pressure.
• Industrial Durability: Rugged die-cast aluminum construction protects internal components from mechanical stress and debris.
• Precise Modulation: Expertly tuned 3-13 PSIG spring range provides smooth, linear throttling for sensitive HVAC loops.

• What linkage is required for installation? This actuator typically requires an AV-401 valve linkage for proper connection to globe valve stems.
• Can the start point be adjusted? Yes, the MK-4641 features an adjustable start point (±2 psig) to calibrate the actuator precisely to your system's controller.
• Is the diaphragm replaceable? Yes, the beaded molded neoprene diaphragm is designed for easy field replacement to extend the service life of the actuator.

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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.