Instruction Manual
D103211X012
NotchFlo DST Valve
March 2011
14
4. Attach a handle, such as a piece of strap iron secured by stem locknuts, to the valve stem. Rotate the handle
alternately in each direction to lap the seats.
5. After lapping, disassemble as necessary (you may mark the position of the seat ring and cage with a soft tip
marker). Clean the seating surfaces, replace the gaskets, reassemble (taking care to return the seat ring and cage to
their original positions), and test for shutoff. Repeat the lapping procedure if necessary.
Trim Replacement
WARNING
Observe the warning at the start of the Maintenance section.
After all trim maintenance has been completed, reassemble the valve body by following the numbered steps below.
Be certain that all gasketed surfaces have been well cleaned. Key numbers referenced in this procedure are shown in
figures 7 through 12, except where indicated.
CAUTION
Inspect the seat ring, cage, bonnet, and body gasket surfaces. These surfaces must be in good condition, with all foreign
material removed. Small burrs less than approximately 0.076 mm (0.003 inches) in height (the thickness of a human hair)
can be ignored. Scratches or burrs that run across the serrations are not permitted under any conditions, since they will
prevent the gaskets from sealing properly.
1. Install the seat ring gasket (key 12) into the valve body. Install the seat ring (key 4).
2.
For CL600, CL900, and CL1500
v
NPS 4 valves,
install the second seat ring gasket (key 12) onto the seat ring.
For CL1500
w
NPS 6 and CL2500 valves,
install the first cage gasket (key 65) onto the seat ring.
3. Install the cage.
4.
For a NotchFlo DST balanced valve,
install the anti‐extrusion rings (key 63) onto the valve plug (key 5). Install the
seal ring (key 8) onto the valve plug (key 5). Install the ring with the open side facing the valve plug stem end of the
valve plug for flow‐up applications (view A of figures 7 through 12). Slide the backup ring (key 9) onto the valve
plug. Secure with the retaining ring (key 10).
5. Install the valve plug into the cage.
6. Install the bonnet gasket (key 11).
For CL1500
w
NPS 6 and CL2500 valves,
install the second cage gasket (key 65)
onto the cage.
7. Install the bonnet over the valve stem and onto the valve body.
Note
The prelubricated hex nuts (key 14) referred to in step 8 can be identified by a black film coating on the nut threads.
The proper bolting procedures in step 8 include‐‐but are not limited to‐‐ensuring that the bonnet stud threads are clean, and that
the hex nuts are evenly tightened to the specified torque values.