Change Diapragm Actuator from Fail Close to Fail Open

How-To  Change from Fail Open to Fail Close

KOMOTO AO-3600  Change from Fail Open to Fail Close

KOMOTO AO-3600  Change from Fail Close to Fail Open

Step by Step Instructions:

WARNING: KOMOTO AO-3600 Actuators with preloaded springs are under tension. They can be identified by three long bolts protruding from the bottom of the actuator. These should be removed last, and installed first upon re-assembly.

1. With the actuator removed from the valve, unscrew the nuts and bolts on the diaphragm case.
    
2. Lift off the top diaphragm case.
    
3. Remove the diaphragm plate assembly consisting of the diaphragm plate, diaphragm, and actuator stem from the actuator case.
    
4. Remove the springs.
    
5. Clamp the bottom section of the actuator stem into a vise using protective jaws, ensuring the actuator stem is not damaged.
    
6. Remove the collar nut.
    
7. Remove the diaphragm plate from the actuator stem, flip upside-down and place them back onto the actuator stem.
    
8. Re-install the collar nut.
    
9. If necessary, apply a suitable lubricant to the actuator stem.
    
10. Install the diaphragm plate assembly together with the actuator stem pointing downward into the bottom diaphragm case.
     
11. Place the springs onto the diaphragm plate, centering them in the intended recesses. The final actuator spring range will determine the appropriate springs to be installed.
     
12. Place the top of the actuator case onto the assembly. Ensure that the air connections on the cases are correctly aligned with each other.
     
13. Fasten the top and bottom diaphragm cases together using the nuts and bolts. Observe tightening torques