The preload tension on the actuator sanitary valve should be adjusted so that the sanitary valve plug begins to lift at the correct signal pressure when the full process pressure is acting upon the plug. (Air to Open valve)
Adjusting Preload
1. With full process pressure acting on the sanitary valve, connect the air signal to the actuator and note at what signal pressure the sanitary valve plug begins to lift.
2. If plug lifts below the lower signal limit (3 or 6 PSIG depending upon range) screw valve stem out of the actuator stem. Apply air to the actuator so that the plug is not turning on the seat while making the adjustment.
3. If the plug does not lift until significantly over the lower signal limit screw the valve stem further into the actuator stem
4. Adjust the valve stem until the valve is shut off at 3 PSI signal but lifts just above this pressure.
5. Once adjustment is complete lock valve stem position using the two stem nuts. Note: A valve that has been set to lift at 3 PSI with full process pressure will lift at a considerably higher start pressure when the process pressure is removed.
Adjusting Preload
1. With full process pressure acting on the sanitary valve, connect the air signal to the actuator and note at what signal pressure the sanitary valve plug begins to lift.
2. If plug lifts below the lower signal limit (3 or 6 PSIG depending upon range) screw valve stem out of the actuator stem. Apply air to the actuator so that the plug is not turning on the seat while making the adjustment.
3. If the plug does not lift until significantly over the lower signal limit screw the valve stem further into the actuator stem
4. Adjust the valve stem until the valve is shut off at 3 PSI signal but lifts just above this pressure.
5. Once adjustment is complete lock valve stem position using the two stem nuts. Note: A valve that has been set to lift at 3 PSI with full process pressure will lift at a considerably higher start pressure when the process pressure is removed.
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