The Barber Colman MK-7821 Actuator is a floor-mounted pneumatic damper actuator designed for controlling inlet vanes on small or medium fans or large jackshafted dampers. It operates within a no-load range of 55-90 kPa (8-13 psig) and can withstand a maximum air pressure of 207 kPa (30 psig). This actuator is equipped with a spring-return mechanism and features a durable, molded neoprene rubber diaphragm that ensures longevity and reliability. It comes standard with a positive positioner for accurate control.
The actuator is housed in a robust unit that includes barbed brass fittings suitable for 1/4″ O.D. plastic tubing, negating the need for clamps. It functions effectively within ambient temperature limits ranging from -29°C (-20°F) to 71°C (160°F). The MK-7821 Actuator is engineered for seamless installation, shipped bolted to a wooden pallet for protection during transit. Installation involves securing the mounting bracket to the floor and connecting the actuator to the driven equipment, such as dampers or fans, using the provided adjustable connecting rod and clevises.
For optimal performance, the actuator should be positioned such that no side loading is applied to the levers, and the connecting rod forms a 90-degree angle with the actuator’s jackshaft centerline at the stroke endpoints. The MK-7821 delivers a torque output of 35.5 to 40.6 N-m (315-360 lb-in) with a diaphragm area of 129 square centimeters (20 square inches). It ensures precise and responsive control, making it suitable for various HVAC applications where reliability and efficiency are paramount.
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| Manufacturer | Barber Colman |
| Part Number/Catalog No. | MK-7821 |
| Series | MK |
| Type | Actuator |
| Weight | 25 Pounds |
| Single/Double | Single |
| Operating Temp. | -29°C (-20°F) to 71°C (160°F) |