VA-4233 Series Electric Valve Actuators use a stepper motor to accurately position control valves in HVAC applications. In the event of a power failure, a spring in the actuator automatically returns the valve to the full stem-up position. These direct-mount, spring-return electric actuators provide a minimum 61 lbs [271 N] force output for floating control, and can be easily field mounted or ordered factory coupled to Johnson Controls 1/2 Inch through 1-1/4 Inch VG7000 Series Bronze Control Valves, with no additional linkages required. The VA-4233 Series can also be field mounted to select Barber-Colman valves, using mounting kits available from Johnson Controls. Proportional control models include an AUTO stroke calibration feature that eliminates the need for manual calibration or adjustment after installation. Integral auxiliary switches are available to indicate end-stop position or to perform switching functions. All models feature a hand crank for manual positioning of the valve, independent of a power supply.