9650 Valve Series
Installation and Maintenance Manual
32
6.2
MAINTENANCE – 3 PIECE THREADED/SOCKET WELD VALVES
Caution: following ANY valve maintenance it is required to fully test valve operation and to complete fps valve
automated valve repair check sheet FP081.0.
NOTE: FPS DOES NOT AUTHORIZE BODY OR ACTUATOR REPAIRS ON FM APPROVED VALVES. PLEASE CONTACT
THE FACTORY FOR ANY REPLACEMENT OF VALVE OR ACTUATOR.
CAUTION: BALL VALVES CAN TRAP FLUIDS IN THE BALL CAVITY WHEN CLOSED. RELIEVE LINE PRESSURE PRIOR TO
SERVICING VALVE.
Rebuilding:
A repair kit may be ordered for these valves, consisting of seats, stem seals, stem O-ring, gland packing and gaskets.
See Section 9 for applicable part numbers.
To replace the seats and seals:
Disassembly (Refer to exploded view of threaded/socket weld valve):
1)
Ensure valve is in its fail-safe (not actuated) position fully open or closed position before disassembly. Pressure
trapped in the valve or actuator if partially stroked could be hazardous.
2)
De-pressurize process media and instrument air and turn off electrical power to the valve before attempting
any repair.
3)
Remove the handle/actuator/solenoid /limit switch.
4)
Place the valve in the open position using a wrench on the valve stem.
5)
Remove the end cap bolts.
6)
Separate the end caps from the valve body.
7)
Remove old seats and ball.
8)
Remove the valve stem from the bottom of the valve body including the stem seals and O-ring.
9)
Remove the gland packing from the top of the valve body.
10)
Clean all sealing surfaces of the valve including the ball.
Notes:
The ball and surfaces against which the seats and seals are installed must be undamaged, clean and free of pit marks
and scratches. Light marring from the action of the ball against the seats is normal and will not affect the operation
of the valve. Flaws which can be seen but not detected with fingertips are acceptable. The stem and body surfaces
that the thrust bearings and stem seals contact must be undamaged, clean and free from pit marks and scratches.
For Socket Weld connection valves, special care must be taken when welding the pipe to the valve as soft seat seals
(ie PTFE, Teflon) are used. The following precautions and procedures must be taken:
1)
Welding cannot be applied to the valve when assembled.
2)
The end cap must be removed prior to welding.
3)
The following procedures must be taken:
a.
remove the end cap from the valve
b.
weld the straight pipe to the end cap
c.
wait until the end cap has cooled down
d.
fit the end cap to the valve body; see section 6, page 10 for body bolt torque
Assembly (Refer to exploded view of threaded/socket weld valve):
1)
Lightly lubricate the ball and seats with AeroShell Grease 22.
2)
Place new gland seal on top of the valve body.
3)
Place new stem seals, and O-ring on stem.
4)
With the stem in the closed position replace the ball and seats. The scribed line on the top indicates direction
of flow through the ball.
5)
Place valve in the open position.
6)
Ensure that all seats and body seals are in the correct position.
