Honeywell M847D-ZONE Truezone Replacement Actuator The M847D is a two position, 24 Vac spring return actuator designed to operate ARD, EARD and ZD zone dampers. Low voltage, spring-return damper actuator. Equipped with anti-rotation and drive shaft extensions for direct mounting to 7/16 inch diameter coupling style dampers. Adjustable range stops. Direct replacement for M847D1004