Schneider Electric (Barber Colman) MK4-3121 Actuator 30067439-890 or system lockouts caused by

or system lockouts caused by pressure switches detecting out-of-range parameters

Built for high-cycle reliability in commercial and residential applications

typically in HVAC or industrial automation environments

manifold pressure setting to ensure optimal burner performance and efficiency

Schneider Electric (Barber Colman) MK4-3121 Actuator 30067439-890 or system lockouts caused byThe Schneider Electric MK4 3121 is a commercial grade pneumatic damper actuator engineered for precise proportional control in complex HVACR systems. Designed as a direct successor in the Barber Colman lineage, this unit features a rugged die cast aluminum housing and a high performance beaded molded neoprene diaphragm for maximum durability. It operates within an 8 to 13 psi spring range and includes a factory installed positive positioner