NIBCO Technical Services • Phone: 1.888.446.4226 • Fax: 1.888.336.4226
14
IX.
KEY DRIVE REPLACEMENT INSTRUCTIONS
– 2” THRU 12” UL / FM BUTTERFLY
VALVES
NOTES:
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. See Fig. 9.
2.
Remove the four (4) hex head cap screws (C) that fasten the gear operator (D) to the valve.
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 (F).
7.
With drive adapter 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 hand wheel
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 (securely tighten), replace flag on stem
and then tighten set screw on flag.
9.
Check operation of valve by turning hand wheel from fully OPEN to fully SHUT position.
FIGURE 9
Tools Required
All valves
1/8” Hex Allen Wrench
2” – 8” valves
9/16” Socket Wrench
10” – 12” valves
3/4” Socket Wrench
TABLE 7
