EZ-C, ET-C, and EWT-C Valves
Instruction Manual
Form 5376
August 2006
11
Design ET-C and EWT-C Valve Plug
Maintenance
CAUTION
To avoid the valve plug seal ring (key
28) not sealing properly and affecting
valve performance, be careful not to
scratch the surfaces of the ring groove
on the valve plug or any of the
surfaces of the replacement ring.
1. With the valve plug (key 2) removed, according to
the disassembly portion of the Trim Maintenance
procedure, proceed as follows:
2. The spring-loaded seal ring may be removed by
first working the retaining ring (key 27) off with a
screwdriver. Then carefully slide the metal backup
ring (key 29) and seal ring (key 28) off the valve plug
(key 2).
3. A spring-loaded seal ring must be installed so
that its open side faces toward the valve stem, or
toward the seat of the plug depending on flow
direction, as shown in view A of figure 9. To install a
spring-loaded seal ring, slide the seal ring (key 28)
onto the valve plug followed by the metal backup
ring (key 29).
4. Then install the retaining ring (key 27) by
inserting one end in the groove and, while turning
the plug, press the ring into the groove. Again, be
careful not to scratch any surfaces of the ring or
plug.
CAUTION
To avoid weakening the stem that may
cause failure in service, never reuse an
old stem with a new valve plug. Using
an old stem with a new plug requires
drilling a new pin hole in the stem,
which will weaken the stem. However,
a used valve plug may be reused with
a new stem.
5. To replace the valve stem (key 7), drive or drill
out the pin (key 8). Unscrew the valve plug from the
stem.
6. Screw the new stem into the valve plug. Tighten
to the torque value given in table 5. Refer to table 5
to select the proper drill size. Drill through the stem
using the hole in the valve plug as a guide. Remove
any chips or burrs and drive in a new pin to lock the
assembly.
Design ET-C and EWT-C Trim Assembly
Key number locations are shown in figure 9, unless
otherwise noted.
1. Install the seat ring gasket (key 13), and seat ring
(key 9) or disk seat (key 22). With composition seat
constructions, install the disk (key 23) and disk
retainer (key 21).
2. Install the cage (key 3). Any rotational orientation
of the cage with respect to the valve body is
acceptable.
3. Lower the valve plug (key 2) and stem assembly
into the cage. Make sure the seal ring (key 28) is
evenly engaged in the entrance chamfer at the top of
the cage (key 3) to avoid damaging the ring.
4. Place the gaskets (keys 12 and 10) and the shim
(key 51) on top of the cage.
5. With an 8-inch Design ET-C or 10X8 Design
EWT-C valve, install the load ring (key 26).
6. Mount the bonnet on the valve body and
complete assembly using the Replacing Packing
procedures in the Maintenance section. Torque
guidelines for body-to-bonnet bolting are shown in
table 4.
7. If the valve has soft metal-to-metal seats, refer to
the Coining Soft Metal-to-Metal Seats section,
below.
Coining Soft Metal-to-Metal Seats
Soft metal-to-metal seat constructions consist of a
valve plug with hardfaced CoCr-A seat and a
non-hardfaced S31600 seat ring. For optimum
shutoff performance of these constructions, coin
seats by stroking the valve plug into the seat ring at
least three times with maximum actuator force.
CAUTION
To avoid possible product damage
which may affect performance, do not
lap soft metal-to-metal seats.