Types 66, 66Z, and 66ZZ
9
instructions. Continue to step 7 if further
disassembly is required.
7. Remove the lower diaphragm plate (key 4), the
top stem gasket (key 18), the diaphragm spacer
(key 16), the middle stem gasket (key 18), and
the upper balancing diaphragm plate (key 15).
8. To aid in assembly, record the position of the
lower diaphragm casing with respect to the valve
body. Unscrew and remove the cap screws
(key 20) and washers (key 34) that hold the lower
diaphragm casing to the valve body (key 1).
Remove the lower diaphragm casing (key 3).
9. Remove and inspect the balancing diaphragm
(key 14) and the gasket (key 35).
If no further maintenance is required, proceed
to steps 5 through 19 in the Assembly section.
For further disassembly, proceed with step 10.
10. Remove the lower balancing diaphragm plate
(key 15) and the lower stem gasket (key 18).
11. Remove the 5/16-inch (7,94 mm) or smaller rod
from the valve body pipe plug hole so that the
valve plug and stem assembly can be moved.
Slide a seat ring puller, T-wrench, or other
suitable tool over the valve plug stem. Engage
the tool with the seat ring lugs. If a suitable
tool will not fit over the valve plug stem, remove
the valve body bottom flange (key 7) using
steps 1 and 2 of the Replacing Plug O-Ring
or Metal Seated Valve Plug section and remove
the valve plug and stem assembly. Unscrew
the seat ring (key 11).
Assembly
1. Apply a good grade of piping compound to the
seat ring (key 11) threads. Thread in the seat ring
using the seat ring puller or a similar device. Wipe
off any excess piping compound.
2.
if the valve plug and stem assembly was not
removed,
proceed to step 3.
if the valve plug and stem assembly was
removed,
place the assembly in the valve body
and insert the 5/16-inch (7,94 mm) or smaller
rod through the pipe plug and valve stem holes.
Use steps 5 through 7 of the Replacing Plug
O-Ring or Metal Seated Valve Plug section to
secure the bottom flange (key 7).
3. Place the lower stem gasket (key 18) on the
valve plug stem (key 13).
4. Place one balancing diaphragm plate (key 15) on
the valve plug stem (key 13) with “cupped” side
facing the valve plug.
5. Align the gasket (key 35) holes with the valve body
pitot tube and cap screw holes and place the
gasket on the valve body.
6. Align the balancing diaphragm (key 14), pitot tube
(key 12), and cap screw holes with the holes in the
valve body and place the balancing diaphragm on
top of the gasket (key 35).
7. Align the lower diaphragm casing (key 3) using the
position recorded in the Disassembly section
step 8 so that the pitot tube (key 12) will be open.
Secure the casing (key 3) with the washers
(key 34) and cap screws (key 20), tightening
the cap screws using an even, crisscross pattern.
8. Place the balancing diaphragm plate (key 15) on
the balancing diaphragm so that the “cupped” side
of the plate faces the main diaphragm (key 5).
9. Place the middle stem gasket (key 18) on top of
the balancing diaphragm plate.
10. Slide the diaphragm spacer (key 16) onto the
valve plug stem.
11. Place the upper stem gasket (key 18) on the
valve plug stem.
12. Position a diaphragm plate (key 4) so that its
“cupped” side faces the balancing diaphragm.
13. Align the main diaphragm cap screw holes with
the diaphragm casing cap screw holes and place
the diaphragm (key 5) on the diaphragm plate
(key 4).
14. Place another diaphragm plate (key 4) on the main
diaphragm (key 5) so that the plate “cupped” side
faces the main spring (key 6).
15.
For the Types 66 and 66Z regulators,
place
the lower spring seat (key 17) and the washer
(key 36) on the valve plug stem. Secure these
parts with the stop nut (key 23).
For the Type 66ZZ regulator,
screw on a stop nut
(key 23) to secure the diaphragm plates (key 4).
