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Schneider Electric MK-7821, MK-7921 Floor Mounted Damper Actuators

Floor Mounted Damper Actuators
MK-7821, MK-7921

For proportional pneumatic actuator used to control inlet vanes on small and medium size fans or large jackshafted dampers.


• Dual actuators, operating a single shaft and piloted by a position, provide maximum capacity for heavy loads.
• Lever with multiple holes facilitates stroke adjustment to suit various applications.
• Rigid steel base provides firm actuator support.


Select a link under the "item" tab below to order.

Cat #Diaph.Area (Total) in.² (cm²)4(102)5(127)6(152)7(178)8(203)9(229)10(254)11(279)12(305)13(330)Max.Torque Power Stroke Ib-in.(N-m)Return Stroke Ib-in.(N.m)Nominal Torque for Proportional Controlª Ib-in.(N-m)
MK-7821 Single20(129)135(600)108(480)90(400)77(343)68(302)60(267)54 (240)49(218)45(200)42(187)315 (35.5)630 (71.0)360(40.6)67.5 (7.6)
MK-7921 Dual40(258)270(1201)216(961)180(801)154(685)136(605)120 (534)109(465)98(436)90(400)84(374)630 (71.0)720(81.2)135 (15.2)
Housing: Die cast aluminum
Diaphragm: Replaceable beaded molded neoprene
Assembly: Actuator(s) and positive positioner (AK-42309-500) are factory mounted on a frame of channel and angle iron
Rotary output: Provided by a driving lever arm connected to a bearing supported jackshaft
Stroke: Rotary output of 60° driving lever arm connecting point adjustable from 4 to 13 in. (102 to 330 mm), in 1 in. (25.4 mm) increments, from centerline of jackshaft
Nominal damper area: Actuator sizing should be done in accordance with damper manufacturer’s specifications
Connecting linkage: AM-394 adjustable 15-3/4 to 24-3/4 in. (400 to 629 mm) is included to link actuator to damper
Spring: Retracts actuator shaft on loss of air pressure
Maximum air pressure: 30 psig (207 kPa)
Ambient temperature limits:
Shipping: -40 to 160°F (-40 to 71°C)
Operating: -20 to 160°F (-29 to 71°C)
Air connections: Barbed fitting for 1/4 in. plastic tubing
Mounting: Floor
Dimensions: 30-1/2 H x 16 W x 20 D in. (775 x 406 x 508 mm)


30-1/2 H x 16 W x 20 D in. (775 x 406 x 508 mm)

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