Instruction Manual
D103357X012
24003 Valve
January 2014
5
3. Unscrew the bonnet (key 3) by turning in a counterclockwise direction from the valve body (key 1). Lift the bonnet
up and off the plug and stem assembly (key 4).
4. Unscrew the lower seat ring retainer (key 5) from the valve body (key 1) and remove the plug and stem assembly
(key 4) (see figure 2). Wipe the parts with a clean soft cloth and examine for signs of wear.
Lapping the Valve Seat
If valve seat leakage becomes excessive, it may be necessary to lap the valve seat.
Lapping is the process of mating the valve plug to the seat ring, with an abrasive to produce a close fit. When valve seat
leakage becomes excessive, lapping becomes necessary. The plug and seat ring seating surfaces should be free of
large scratches or dents and the contact surface of the seats should be as narrow as possible.
1. Use a good quality lapping compound with a mixture that contains 280 to 600 grit. Apply at several spots around
the plug seating surface.
2. Replace the plug and stem assembly (key 4) through the bottom of the valve body (key 1) and screw in the lower
seat ring retainer (key 5).
3. Place the bonnet (key 3) loosely into the valve body to serve as a guide during the lapping operation.
4. Rotate the plug and stem assembly (key 4), applying light pressure to the plug/seat mating surface.
5. Lap as little as possible. Excessive lapping will shoulder the seat ring, and will not improve the seating. Repeat for
the second seating surface.
6. Clean the valve seats and plug thoroughly when the lapping is complete.
Replacing Packing
Refer to figure 2 and the standard and optional packing constructions (figures 3, 4, and 5) to determine the packing
that has been preinstalled in your valve.
1. Mount the valve in a vise.
2. Remove actuator, stem locknuts (key 27), travel indicator (key 58), packing follower (key 7), and yoke drive nut (key
8) per actuator instructions D103352X012.
3. Unscrew the bonnet (key 3) by turning in a counterclockwise direction from the valve body (key 1). Lift the bonnet
up and off the plug and stem assembly (key 4). Push the old packing out from the underside of the bonnet (key 3).
4. Standard Spring Loaded PTFE V-Ring Packing (figures 2 and 3): Carefully insert each piece in exact order shown in
figure 3. Turn the packing follower (key 7) until it shoulders on the bonnet (key 3). This will compress the packing
spring (key 9) to enable constant stem sealing throughout packing life.
5. Molded Graphite Ribbon Packing (figure 4): Carefully insert each piece in exact order shown in figure 4. Hand
tighten the packing follower (key 7). Use a wrench to increase tightness by turning the nut an additional 60
degrees.
6. ENVIRO-SEAL Packing (figure 5): Carefully insert each piece in exact order as shown in figure 5. Tighten the packing
follower (key 7) until the Belleville springs are compressed. This will be signaled by a significant increase in
resistance. Back off the follower 1/8 to 1/4 turn. A gap of approximately 1/16 inch between the packing follower
and the bonnet will ensure packing is seated properly.
CAUTION
Overtightening the packing may prevent stem movement and valve operation and result in equipment damage or loss of
control of the process.