NIBCO Rubber-Seated Butterfly Valves - Manual (Page 10)

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VII. KEY DRIVE REPLACEMENT INSTRUCTIONS –
2” THRU 12” UL / FM BUTTERFLY VALVES
NOTE: All replacement parts must be obtained from your NIBCO distributor. Key drive
material and size is specifically designed to meet performance requirements of UL and
FM. Failure to use the properly sized replacement parts may void the UL and FM ratings.
Drive Key (section of weakness) will shear if excessive torque is applied to the input of
the gear operator while the disc is blocked partially open.
1. Loosen the set screw (B) that secures the flag (A) to the stem. Remove the flag.
2. Remove the four (4) hex head cap screws (C) that fasten the gear operator (D) to the
valve. The wrench sizes are 9/16” for 2” – 8” valves and 3/4” for the 10” – 12” valves.
3. Lift the gear operator straight up from the valve. In most cases the adapter bushing (F)
will stay in the segment quadrant gear because the broken key causes interference
between the gear and adapter bushing.
4. Pull the adapter bushing from the gear. Some force may be required.
5. After removing the adapter bushing, remove the broken key.
6. Place the new key in keyway of adapter bushing.
7. With drive bushing and key in place within gear operator, carefully slide the gear
operator over stem until it rests flush on the valve operator mounting flange. The
handwheel may need to be turned in order to align bolt holes and the orientation pin.
8. Secure gear operator with four (4) hex head screws, replace flag on stem and then
tighten set screw on flag.
9. Check operation of valve by turning handwheel from fully open to fully closed position.
NOTE BEFORE ASSEMBLY: All replacement parts must be obtained from the
manufacturer to assure proper operation of the valve. Parts are available from your
NIBCO distributor.