Jordan Valve Mark 128PQC Series Control Valve - Manual (Page 4)

M
ark
128PQC S
erieS
C
ontrol
V
alVe
Changing Main Spring Range
Unless otherwise indicated, refer to Table 2 for parts
listings for replacement packing and trim assembly,
Figure 2 for packing and trim assembly key numbers
and Figure 4 for control valve assembly key numbers.
1. Isolate off the control valve from all pressure,
and release pressure from valve body and
actuator.
2. Release pressure and drain the process
media from both sides of the valve body. En-
sure the valve is completely closed.
3. If necessary, disconnect the input signal tub-
ing; remove the diaphragm casing nuts (Key
15), cap screws (Key 14) and upper dia-
phragm casing (Key 1).
4. For fail-close action applications, install main
springs (Key 12), using quantities and de-
scriptions as outlined in Table 2.
Note: It is important to avoid loosening the
stem-nut (Key 15), as this may prevent the
valve from shutting off or from fully opening at
full pressure, and resulting in the need for
complete disassembly of the control valve to
properly install the stem and diaphragm.
5. For fail-open applications, unfasten the lock
nut (Key 16), remove the flat washer (Key
33), diaphragm (Key 35), diaphragm plate
(Key 34), spring plate (Key 2), and main
springs (Key 12).
6. Refer to Table 1 and install main springs as
indicated.
7. Reassemble the removed parts (Keys 2, 34,
35, 33, and 16). The locknut (Key 16) must
be tightened to 12 foot-pounds (16 N•m).
8. Attach the upper diaphragm casing using the
cap screws, and casing nuts, tightening in an
even crisscross pattern to avoid crushing the
diaphragm. Tighten to 15 foot-pounds
(20 N•m).
9. Reconnect the input signal tubing to the
actuator connection of the appropriate dia-
phragm casing.
Reversing Action or Replacing Actuator Parts
Unless otherwise indicated, refer to Table 2 for parts
listings for replacement packing and trim assembly,
Figure 2 for packing and trim assembly key numbers
and Figure 4 for control valve assembly key numbers.
1. Isolate the control valve from all pressure,
and release pressure from valve body and
actuator and ensure the valve is completely
closed.
2. Remove the input signal tubing, diaphragm
casing nuts (Key 15), cap screws (Key 14)
and upper diaphragm casing (Key 1).
3. Remove the following:
3.1. Main springs (Key 12)
3.2. Stem nut (Key 15)
3.3. Locknut (Key 16) and lock washer
(Key 4)
3.4. Spring plate (Key 2)
3.5. Diaphragm plate (Key 34) and
diaphragm (Key 35)
3.6. Flat washer (Key 33)
4. Unscrew the four nuts (Key 32) from the
screws of the lower diaphragm casing. After
disconnecting the input signal tubing,
remove the actuator from the valve body
along with attached trim parts.
5. Remove the following:
5.1. Valve plug (Key 25)
5.2. Packing box washer (Key 27)
5.3. Slide the packing box (Key 28), O-
ring retainer (Key 18), stem O-ring
(Key 19) and the diaphragm casing
O-ring (Key 31) off the stem.
6. Replace the valve stem, bottom stem nut or
lock nut (Key 15 or 16) as required.
7. Refer to Figure 3 and ensure that the lower
shoulder of the bottom stem nut (Key 15) (for
fail-open assembly) or locknut (Key 16) (for
fail-close assembly) is the proper distance
from the plug end of the stem.
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