page 10
ASSEMBLY OF MAIN PMX ACTUATOR ASSEMBLY
1. Check actuator operating stem for surface nish condition and ID threads. Apply never seize to internal threads.
2. Clean and inspect groves of down stop. Grease thoroughly and install two down stop seal O-rings in the down stop.
3. Slide drift shims over the male stem and then place the down stop on top of the shims.
4. Place operating stem down onto the male stem and rotate clockwise to engage.
5. Place stem shoulder ring down and onto the OD of the actuator operating stem, stopping on shoulder.
6. Grease thrust bearing and place it onto the top of the stem shoulder ring.
7. Place spring over bonnet nose and nest properly in the lower plate.
8. Place the piston on a at surface. Install stem seal o-ring into piston. Grease thoroughly using Dow Corning 111 or equivalent.
9. Slide the ID bore of the piston over the actuator operating stem. Push continuously until the piston sets on the thrust bearing
and exposes the retainer ring groove on the operating stem.
10. Install the piston retainer bushing into the top of the piston counter bore. The piston retaining ring must be installed properly
for the bushing to keep the piston retaining ring captured. Grease area slightly. Install spiral wound retainer ring.
11. Place lower plate/bonnet assembly in a vertical position as installed on a valve.
12. Place piston and operating stem assembly down onto spring and center carefully. Rotate clockwise to engage male stem.
13. Install the handwheel split ring on the actuator operating stem groove. Hold the split ring in place and lower the handwheel
down and over the split ring. Seat handwheel carefully.
14. Align hole in the actuator operating stem and handwheel and insert the hex head screw through hole. Place lock washer and
hex nut on the end of the hex head screw and secure tightly.
15. Place at washer over the end of the actuator operating stem and thread a hex head bolt into the end of the operating stem.
16. Set the gate valve drift per instructions in this manual.
17. Remove handwheel once the gate valve drift has been set.
18. Grease thoroughly using Dow Corning 111 or equivalent and install the piston o-ring and backup ring to the o-ring groove on
the outer OD surface.
19. Place two O-rings in the ID grooves of the piston housing.
20. Lube upper shaft and slide piston housing over the top of actuator operating stem down onto piston and lower plate assembly.
21. With the two C-Clamps or some other equivalent method, uniformly depress the piston housing while forcing down until the
cylinder snap ring can be installed in the groove of the piston housing.
22. Insert cylinder snap ring between piston housing and lower plate assembly ring groove to secure.
23. Release tension from C-Clamps.
24. Thread hex bolts and at washer in lower plate assembly holes and tighten.
25. Install relief tting in the NPT port in the top of actuator assembly.
26. Install the handwheel split ring on the actuator operating stem groove. Hold the split ring in place and lower the handwheel
down and over the split ring. Seat handwheel carefully.
27. Align hole in the actuator operating stem and handwheel and insert the hex head screw through hole. Place lock washer and
hex nut on the end of the hex head screw and secure tightly.
28. Place at washer over the end of the actuator operating stem and thread a hex head bolt into the end of the operating stem.
29. Stroke actuator a minimum of three times at operating pressure.
30. Retighten bolts in the bonnet clamp rings on lower part of actuator.
31. Check actuator for leaks and proper operation. Operation should be smooth.
32. Apply Pressure to actuator and stroke three times at operating pressures proper actuation.
33. Open and close valve manually to insure proper operation.
34. Note: Never jam the valve fully open or fully closed. Always back off a quarter (1/4) turn after fully opening and closing to
ensure proper sealing of gate, seat and metal-metal bonnet seal.
