Jordan Valve Mark 128PQC Series Control Valve - Manual (Page 5)

M
ark
128PQC S
erieS
C
ontrol
V
alVe
Reversing Action or Replacing Actuator Parts
cont’d
8. Perform the following assembly sequenc-
es as necessary to achieve the required
control valve action:
8.1. Fail–close action: install the follow
ing parts: flat washer (Key 33),
diaphragm (Key 35), diaphragm
plate (Key 34), spring plate (Key
2), lock washer (Key 4) and stem
nut (Key 15). Tighten stem nut
to 12 foot-pounds (16 N•m).
8.2. Fail-open action, install the follow-
ing parts: lock washer (Key 4),
spring plate, diaphragm
plate, diaphragm, flat washer (Key
33) and locknut (Key 16). Tighten
the lock nut to 12-foot-pounds (16
N•m).
9. With fail-open application, place the main
springs (Key 12) into the lower diaphragm
casing, ensuring that the lower ends of the
springs rest over the weld stud heads of
the lower diaphragm casing.
10. Following steps 6 through 10 of the “Re-
placing Packing and Trim” section, install
packing and trim parts to secure the stem.
11. When reversing action from previous direc-
tion, move the vent (Key 3) to the 1/4-inch
NPT actuator connection of the lower
diaphragm casing (for fail-open action) or
upper diaphragm casing (for fail-close ac-
tion).
12. For fail-close application, place the main
springs so that they rest in the spring plate
holes and will not touch the upper dia-
phragm casing vent boss.
13. Mount the upper diaphragm casing, cap-
screws, and casing nuts, tightening in an
even crisscross pattern to avoid crush
ing the diaphragm. Tighten to 15
foot-pounds (20 N•m).
14. Replace the actuator and attached trim
parts into the valve body (Key 26) with nuts
(Key 15) to the lower diaphragm casing
integral assembly screws. Tighten nuts to
15 foot-pounds (20 N•m).
15. Reconnect the input signal tubing to the
actuator connection of the appropriate
diaphragm casing.
P
arts
o
rderIng
Mark 128-PQC valves have individual serial numbers,
found on the valve nameplate. Please refer to that
number when ordering parts or contacting your Jordan
Valve Sales Representative. Individual parts numbers
are listed as follows. Please include these numbers
when ordering replacement parts.
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