Parts Ordering - Fisher 128-PQC Instruction Manual

If the valve is equipped with an optional handjack, be
sure the handjack assembly is not restricting the valve
from closing. Rotate the handles or handjack body
(key 48 or 47 in figure 9), if necessary, to allow the
main springs (key 19) to close the valve. Unscrew the
handles or pipe plugs and remove the indicator cover
(key 41 in figure 9). Drive out the groove pin (key 50 in
figure 9) and remove the stem nut and thrust washer
(keys 49 and 51 in figure 9).
The optional handjack is used only with spring-close
valves. If changing the action of a spring-close valve
with a handjack to spring-open action, the only func-
tion the handjack performs is to restrict the valve from
closing.
2. Disconnect the input signal line and remove the
diaphragm casing nuts (key 14), cap screws (key 21),
and upper diaphragm casing (key 20).
3. Remove the main springs (key 19), stem nut
(key 14), locknut (key 46), lock washer (key 29),
spring plate (key 18), diaphragm plate (key 17), dia-
phragm (key 16), and flat washer (key 15).
4. Remove the four nuts (key 14) from the integral
screws of the lower diaphragm casing. Lift the casing
and attached trim parts off of the valve body.
5. Unscrew the valve plug (key 3A) and remove the
packing box washer (key 4).
6. Pull the packing box (key 9), O-ring retainer
(key 39), O-ring (key 11), and diaphragm casing O-
ring (key 35) off the stem.
7. Remove the stem (key 3B), and replace it, the bot-
tom stem nut (key 14), or the locknut (key 46) as nec-
essary.
8. When reinstalling the stem nut (key 14) or locknut
(key 46), make sure the distance between the bottom
shoulder of the nut and the plug end of the stem is
equal to dimension A in figure 6.
9. Begin the following procedure as appropriate, de-
pending on whether the desired control valve action is
spring-close or spring-open.
For spring-close action, install the flat washer
(key 15), diaphragm (key 16), diaphragm plate (key
17), spring plate (key 18), lock washer (key 29), and
stem nut (key 14). Tighten the stem nut to 12 lbf ft
(16 N m).
For spring-open action, install the lock washer
(key 29), spring plate (key 18), diaphragm plate
(key 17), diaphragm (key 16), flat washer (key 15),
and locknut (key 46). Tighten the locknut to 12 lbf ft
(16 N m).
10. For spring-open action only, install the main
springs (key 19) into the lower diaphragm casing so
that the lower ends of the springs rest over the weld
stud heads of the lower diaphragm casing.
11. Install the stem and diaphragm assembly into the
lower diaphragm casing. For spring-open action, make
sure that the assembly is oriented so that the spring
plate holes fit over the upper ends of the springs.
12. Secure the stem by installing the packing and trim
parts according to steps 5 through 9 of the Replacing
Packing and Trim section.
13. If reversing action from what it was previously,
remove the vent assembly (key 31), and install it in the
1/4-inch NPT connection of the lower diaphragm cas-
ing for spring-open action or the upper diaphragm cas-
ing for spring-close action.
14. For spring-close action only, install the main
springs, making sure they rest in the spring plate holes
and will not ride on the upper diaphragm casing vent
boss.
15. Install the upper diaphragm casing, cap screws,
and casing nuts. To avoid crushing the diaphragm,
tighten the cap screws and nuts evenly in a crisscross
pattern to 15 lbf ft (20 N m).
16. Install the actuator and attached trim parts back
into the valve body (key 1), and secure with the four
nuts (key 14) attached to the lower diaphragm casing
assembly screws. Tighten the nuts to 15 lbf ft (20
N m).
17. Connect the input signal line to the 1/4-inch NPT
connection of the appropriate diaphragm casing.
18. If an optional handjack is used, reinstall the hand-
jack parts. Be sure to secure the stem nut (key 49 in
figure 9) with the groove pin (key 50 in figure 9).

Parts Ordering

The Type 128-PQC control valve is assigned a serial
number which can be found on the nameplate. A typi-
cal nameplate is shown in figure 2. Refer to the serial
number when contacting your Fisher Controls repre-
sentative or sales office for assistance. When ordering
replacement parts, refer to the serial number and to
the 11-character part number from the following
Parts List .
Parts Kits
Key Description
Type 128-PQC Repair Kits (soft parts only.
Kit includes key 5, 8, 10, 11, 12, and 35)
w/PTFE V-ring packing
w/Nitrile/cotton packing
For additional kit information, see the Replacement Packing
and Trim Assembly Part Number table.
128-PQC
Part Number
RPQCX000012
RPQCX000022
7