Series 816 - S767 ACTUATOR MAINTENANCE

SERIES 816 BUTTERFLY VALVE MAINTENANCE
The AVK S816 butterfly valve requires no scheduled maintenance. The valve should be exercised regularly. To
exercise the valve, open and close through one complete cycle.
S767 ACTUATOR MAINTENANCE
The S767 actuator is shown in Fgure 1. The actuator is factory lubricated with Mobilux EP1 grease. The unit is factory
adjusted, lubricated, and sealed. No adjustment or lubrication should be necessary. If the gear box operates roughly, remove
the cover and inspect for wear. All moving parts should be coated with grease. If necessary coat all moving parts with Mobilux
EP1. Buried gear boxes should be packed 90% with grease.

TROUBLESHOOTING
Leakage between valve and actuator: Replace O-rings
Bottom Trunnion is Leaking: Remove plug and replace O-ring
Leakage at flanges: Tighten Flange Bolts
Valve leaks when closed:
Verify the valve is within its pressure range.
Open and close the valve a few times to flush away any debris that may be in the seating area.
Check that the actuator bolts are tight and the actuator is not rotating back and forth when the valve is operated.
Check that the disc is centered in the valve body. Adjust actuator if necessary. See Stop Nut Adjustment below.

Check that the metal disc edge is free of scale and scratches. If damaged the valve must be returned for repair. Check that the metal disc edge is free of scale and scratches. If damaged the valve must be returned for repair. Check that the rubber seat is not damaged. The rubber seat is bonded to the valve body and cannot be replaced.
If a new rubber seat is required contact Customer Service for authorization and instructions.

REPAIR PROCEDURES
Stem Seal Replacement.
WARNING: Depressurize the line before performing this operation.
1. Remove the actuator
a. Open the valve halfway
b. Remove the actuator mounting bolts
c. Carefully slide the actuator from the valve stem. Do not lose the actuator plate pins or stem keys.
2. Remove the stem cover plate.
3. Using a small tool pull the upper o-ring packing ring off the valve stem
4. Using the same tool remove the o-ring
5. Insert a new o-ring
6. Replace the packing ring
7. Replace the stem cover plate
8. Reinstall the actuator
a. Place the actuator on the stem. Use the keys for round stems
b. Reinstall the actuator mounting bolts and tighten loosely.
c. Reinsert the plate pins.
d. Tighten the actuator bolts to 90 ft-lbs
Stop Nut Adjustment
Valves equipped with traveling nut manual actuators are set in the factory and rarely need to be adjusted. To adjust the stop
nuts.
1. Remove the cover plate
2. Remove the stop nut adjustment pin
3. Loosen the stop nut.
4. Rotate the valve disc until the valve has quit leaking
5. Rotate the stop nut against the slider nut.
6. Rotate the slider nut to the nearest slot that aligns with the adjustment hole.
7. Reinsert the adjustment pin
8. Re-grease if necessary. Mobilux EP1.
9. Reinstall the cover plate. Make sure the slider nut pin is in the guide groove.
Hard to open: Flush the valve by cycling open and closed a few times. Check grease in actuator to make all parts are
adequately lubricated.