Resideo CPRD10 Damper 326058 756 The Johnson Controls VA9104 GGA 2S is The Johnson Controls VA9104 GGA 2S is a heavy duty non spring return actuator designed for proportional control of 1 2" to 2" ball valves in commercial HVAC systems Dual Circuit Control: The DPST N O design allows for simultaneous control of multiple heating banks or a combination of heat and blower stages depending on the static pressure settings and duct run restrictions Adjust the counterweight along the calibrated arm until the blade remains closed during a full system call and only begins to crack open at the designated static pressure limit once zones start closing