Emerson Fisher EHD Instruction Manual page 13

Instruction Manual
D100394X012
Key numbers referenced in this procedure are shown in figure 18 for the EHD valve, figure 19 for the EHS valve, and
figure 20 for the EHT valve except where indicated.
1. Remove the actuator and bonnet by following steps 1 through 4 of the Replacing Packing procedure. Observe all
warnings and cautions.
2. Lift the valve stem and attached valve plug out of the valve body. If the valve plug is to be reused, tape or otherwise
protect the valve plug stem and the valve plug seating surface to prevent scratches.
3. Lift out the cage (key 2) and the top and bottom cage gaskets (key 11). For a valve with Cavitrol III two‐or
three‐stage cage, also remove the O‐ring (key 26, figure 21) that fits between the cage and the seat ring (key 6).
Constructions other than TSO trim
1. Use the seat ring retainer tool (figure 9) to remove the seat ring retainer (key 7) as follows:
a. Insert the tool into the valve body. Be certain the tool lugs are engaged in the corresponding recesses in the
retainer.
b. Use a power torque wrench or driver having torque capabilities equal to or greater than those shown in table 9.
Connect the torque wrench to an extension if necessary. The tool or extension must snugly fit the square hole in
the seat ring retainer tool. Refer to figure 9 for square hole sizes.
c. Insert the tool or extension into the square hole in the seat ring retainer tool.
d. Use the bonnet studs (key 13) to prevent a power torque wrench from rotating.
CAUTION
Hold the torque wrench or driver at right angles to the seat ring retainer when applying torque. Tilting the tool or
extension while applying torque may cause the lugs on the seat ring retainer tool to suddenly disengage from the recesses
in the retainer, damaging the retainer and seat ring.
e. Unscrew and remove the seat ring retainer.
2. Remove the seat ring (key 6) and the seat ring gasket or O‐ring (key 12).
3. Refer to the Valve Plug Maintenance procedure or to the Lapping Seats procedure.
TSO Trim
Refer to figure 7.
1. Remove the retainer, backup ring, anti‐extrusion rings, and piston ring.
2. Remove the set screws that lock the outer plug to the inner plug.
3. Using a strap wrench or similar tool, unscrew the outer plug from the inner plug. Do not damage the outer plug
guide surfaces.
4. Remove the protected soft seat seal (see figure 5).
5. Inspect the parts for damage and replace if needed.
6. Refer to the Valve Plug Maintenance procedure or to the Lapping Seats procedure.
EH (1-1/2x1 through 8x6)
July 2017
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