Schneider Electric (Barber Colman) MK-4611 Proportional Control

The Schneider Electric MK-4611 is a rugged proportional pneumatic valve actuator designed for precise linear control in HVAC systems. Engineered with an 11-square-inch effective diaphragm area, this Barber Colman MK-4611 replacement delivers reliable 5 to 10 PSI spring return action, ensuring the valve defaults to its normal position upon loss of pilot signal. The proportional control actuator features a 1/2-inch nominal stroke and a standard 1/8-inch NPT air connection, making it directly compatible with legacy pneumatic infrastructure. Housed in a durable NEMA 1 enclosure, this unit provides protection for internal components in indoor environments. Field technicians should note that the MK-4611 is functionally identical to the MK-4611-0-0-2, allowing for seamless drop-in installation without piping modifications. Its heavy-duty construction is optimized for modulating hot water, chilled water, and steam flow in medium-sized terminal units where consistent throttling performance is required.

Key Benefits

• Precise Proportional Modulation: Provides accurate linear movement for valve positioning based on varied pneumatic signal pressure.
• Safety-Focused Spring Return: Mechanical spring return ensures a fail-safe position during control air failure.
• Legacy Compatibility: Serves as the direct replacement for Barber Colman pneumatic actuators, maintaining system integrity in older commercial buildings.
• Robust NEMA 1 Housing: Die-cast aluminum construction protects the diaphragm and linkage from mechanical damage.
• Simplified Installation: Standard 1/8" NPT porting and 1/2" stroke length match industry-standard globe valve bodies.

Common Questions

Is the MK-4611 a direct replacement for the MK-4611-0-0-2?
Yes, both model numbers refer to the same 11-square-inch proportional actuator with standard stroke and spring ranges.

What is the effective diaphragm area for this actuator?
This model utilizes an 11-square-inch rolling diaphragm, providing sufficient force for throttling 1/2" to 2" valve bodies.

Can I use this actuator for steam applications?
Yes, provided the valve body packing and ambient temperature at the actuator do not exceed the rated limits of the neoprene diaphragm.

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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.