Schneider Electric Mk4-7121 Pneumatic Actuator

Schneider Electric MK4-7121 Pneumatic Damper Actuator is a spring‑return, proportional HVAC actuator that modulates dampers and two‑/three‑way valve assemblies with precise stroke control. It features an adjustable 4 to 5 inch stroke (typical 4.5 inches) and a 20 in² neoprene diaphragm, delivering up to about 293 lb‑in of torque. The unit operates on 8–13 psi (138 kPa) control pressure and requires a minimum 20 psi supply to the actuator for reliable operation, with a maximum allowable supply of 30 psi (200 kPa). Its die‑cast aluminum housing is rated for ambient temperatures from −20 to 160 °F (−10 to 70 °C), making it suitable for commercial building environments. Designed for use with 2–5 inch two‑way valves and 2–2.5 inch three‑way valves in damper assemblies, the MK4‑7121 can be equipped with a positive positioner VKx4 (AK‑42309‑500) for enhanced control accuracy. This MK4‑7121 variant sits within Schneider Electric’s MK4 family of pneumatic actuators, delivering dependable damper actuation at moderate pressure ranges and enabling precise, energy‑efficient HVAC control.