they must be purchased separately or as part of a seat kit

the switch opens the control circuit to prevent thermal overloading

Where should the external equalizer be installed for this valve

What bearing type does this motor use

Its robust internal geartrain and spring return safety feature guarantee that dampers return to a predetermined position during power loss

Schneider Electric (Barber Colman) MK4-3121 Actuator 340793-762 they must be purchased separatelyThe 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