The Johnson Controls VA-8122-1 Valve Actuator; ELECTRIC; 22# PROP Control 5/16 INCH STRK 24 VAC; 0-10VDC INPUT; 22# FORCE;
The VA-8122 Proportional Valve Actuator is an electric actuator that provides proportional control of valves with up to a 5/16 in. stroke in Heating, Ventilating, and Air Conditioning (HVAC) applications. This compact, non-spring return actuator has a 22 lb minimum seating force in a compact, easy-to-install package. The VA-8122 can be ordered factory coupled to the 1/2 in. or 3/4 in. VG7000 Series bronze valves for hot or cold water service only. The VA-8122 can be used for retrofits of VT Series Terminal Unit Valves (with slotted stems) and VB-5×39 Series Flare Valves.
The actuator uses a reversible synchronous motor to accurately position the valve. The motor can reliably generate 22 pounds of force in either the Drive Down (DD) or Drive Up (DU) direction. Once the valve closes, a shutoff force builds up. When this force reaches 22 pounds, a lever within the actuator operates a force sensor that stops the motor. The constant load at the end of travel ensures tight valve seat shutoff and compensates for seat wear. Field calibration of shutoff is not required. The actuator maintains the shutoff force and its last position even if power is removed.