Trim Replacement - Fisher EWS Series Instruction Manual

Instruction Manual
Form 2376
March 2007
stem or adaptor with a new plug
requires drilling a new pin hole in the
stem (or adaptor in case an
ENVIRO-SEAL bellows seal bonnet is
being used). This drilling weakens the
stem or adaptor and may cause failure
in service. However, a used valve plug
may be reused with a new stem or
adaptor except with Cavitrol III trim.
The valve plug and valve plug stem for
Cavitrol III trim are a matched set and
must be ordered together. If the
Cavitrol III valve plug or valve plug
stem is damaged, replace the entire
assembly (key 2, figure 26 and 27).
2. To replace the valve stem (key 7), drive out the
pin (key 8). Unscrew the valve plug from the stem or
adaptor.
3. To replace the adaptor (key 24, figure 21) on
ENVIRO-SEAL bellows seal bonnets, place the plug
stem assembly and valve plug in a soft-jaw chuck or
other type of vise so that the jaws grip a portion of
the valve plug that is not a seating surface. Drive out
the pin (key 36, figure 21). Reverse the plug stem
assembly and valve plug in the soft-jaw chuck or
vise. Grip the flat areas on the valve stem just below
the threads for the actuator/stem connection.
Unscrew the valve plug/adaptor assembly (key 24,
figure 21) from the valve stem assembly (key 20,
figure 21).
4. Screw the new stem or adaptor into the valve
plug. Tighten to the torque value given in table 7.
Refer to table 7 to select the proper drill size. Drill
through the stem or adaptor, 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.
5. For ENVIRO-SEAL bellows seal bonnets, grip the
flats of the stem extending out of the top of the
bellows shroud with a soft-jaw chuck or other type of
vise. Screw the valve plug/adaptor assembly onto
the valve stem. Tighten as necessary to align the pin
hole in the stem with one of the holes in the adaptor.
Secure the adaptor to the stem with a new pin.

Trim Replacement

Except where indicated, key numbers in this section
are referenced in figure 22 for Design EWD
constructions, figure 22 for restricted trim detail,
figure 23 for EWS construction, and figure 24 for
Design EWT constructions. Refer to figures 26
Note
Table 7. Valve Stem to Plug Torque and Pin Replacement
VALVE STEM STEM TORQUE,
DIAMETER MINIMUM TO MAXIMUM
mm Inch
NSm
12.7 1/2 81 to 115
19.1 3/4 237 to 339
25.4 1 420 to 481
31.8 1-1/4 827 to 908
and 27 for Cavitrol III, figure 16 for Whisper Trim III,
and figure 29 for WhisperFlo constructions.
1. With a restricted-trim seat ring construction,
install the adaptor gasket (key 14) and seat ring
adaptor (key 5).
2. Install the seat-ring gasket (key 13), seat ring
(key 9), or disk seat (key 22). With a PTFE-seat
construction install the disk and disk retainer
(keys 21 and 23). With an NPS 8x6 CL900 Design
EWT valve with Cavitrol III cage, install the spiral
wound gasket (key 12) on the seat ring.
3. Install the cage or cage/baffle assembly (key 3).
Any rotational orientation of the cage or assembly
with respect to the valve is acceptable. A Whisper
Trim III cage designated by level A3, B3, or C3 may
be installed with either end up. The level D3
cage/baffle assembly or Cavitrol III cage assembly,
however, must be installed with the hole pattern end
next to the seat ring. If a cage retainer (key 31) is to
be used, place it on top of the cage.
4. For constructions other than TSO (tight
shutoff trim), slide the valve plug (key 2) and stem
assembly or valve plug and ENVIRO-SEAL bellows
seal assembly into the cage. Make sure the piston
ring or seal ring (key 6 or 28) is evenly engaged in
the entrance chamfer at the top of the cage (key 3)
or cage retainer (key 31) to avoid damaging the ring.
5. For TSO (tight shutoff) trim constructions,
perform the following steps (refer to figures 7 and 8).
D Thread the outer plug onto the inner plug until
the parts seat metal to metal, using a strap wrench
or similar tool that will not damage the outer plug
guide surfaces.
D Mark the top of the inner plug and outer plug
with alignment marks in the assembled position.
D Disassemble the outer plug from the inner plug
and install the seal over the inner plug, so that the
seal rests below the threaded area.
D Thread the outer plug onto the inner plug and
tighten with a strap wrench or similar tool until the
EW Valve
Data
DRILL SIZE,
INCHES INCHES
LbfSft
60 to 85 0.125
175 to 250 0.1875
310 to 355 0.25
610 to 670 0.25
15