NIBCO High-Performance Butterfly Valve - Manual (Page 8)

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8
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Revised 8/22/2013
Seat Replacement Procedure
7.15 Remove valve from piping per procedure above.
7.16 Place valve on bench with seat retainer (11) facing up. Remove cap screws (10) from retainer. Thread 2 of the removed
cap screws (10) into the 2 threaded holes in retainer (11) at 12 o’clock and 6 o’clock. This will assist in pushing the retainer
(11) from valve body (17).
7.17 Remove old seat (13) and discard.
7.18 Clean seat cavity and retainer (11). Clean, and inspect seal surfaces on disc (14). Polish disc edge to remove any small
scratches that may interfere with disc / seat seal.
7.19 With valve disc in partial OPEN position, install new seat (13) into valve body (17). Install retainer (11) onto seat and align
screw holes. Install cap screws (10) and snug. Position valve disc to CLOSED position. Torque cap screws using the “Cross-
over” diagonal method. Torque screws as follows:
SCREW SIZE TORQUE FT·LBS SCREW SIZE TORQUE FT·LBS
4 mm 4 ft·lbs 8 mm 11 ft·lbs
6 mm 8 ft·lbs 10 mm 15 ft·lbs
7.20 With disc in CLOSED position, visually inspect the disc to assure it is centered in the seat. If not, refer to
Section 4 for proper stop adjustment.
7.21 Open and close valve several times and check for proper operation before placing valve back in service.
Lower Seal Replacement Procedure
7.22 Remove valve from piping per procedure above.
7.23 Remove 4 caps screws (22) and lockwashers (21). Remove body cap (20) being careful not to lose disc spacer (18).
7.24 Being careful not to damage any seal surfaces, remove lower seal (19) from valve body (17) and discard.
7.25 Clean seal cavity and cap (20). Inspect for any damage.
7.26 Install new seal (19) into valve body (17). Install spacer (18), cap (20), cap screws (22), and lockwashers (21). Torque cap
screws evenly using the “Cross-over” diagonal method.
Installation, Operation and Maintenance Instructions
NIBCO 6822 and 7822 Series High Performance Butterfly Valves