Emerson Fisher GX User manual

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FisherrGX
Control Valve and Actuator System
Contents
Introduction 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Scope of Manual 1. . . . . . . . . . . . . . . . . . . . . . . . . .
Description 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Specifications 2. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Valve Installation 2. . . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Actuator Maintenance 4. . . . . . . . . . . . . . . . . . . . .
FIELDVUEtDVC2000 Digital Valve
Controller Mounting 9. . . . . . . . . . . . . . . . . . . . .
Packing Maintenance 11. . . . . . . . . . . . . . . . . . . . .
Replacing Packing 11. . . . . . . . . . . . . . . . . . . . . . .
Valve Trim Maintenance 15. . . . . . . . . . . . . . . . . .
Bellows Maintenance 18. . . . . . . . . . . . . . . . . . . . .
Handwheel Operation 20. . . . . . . . . . . . . . . . . . . . . .
Travel Stop Operation 20. . . . . . . . . . . . . . . . . . . . .
Parts Ordering 34. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Parts Kits 35. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Parts List 36. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Introduction
Scope of Manual
This instruction manual includes installation,
maintenance, and parts information for the Fisher
GX control valve and actuator system.
Do not install, operate or maintain a GX valve and
actuator system without first Dbeing fully trained and
qualified in valve, actuator and accessory
installation, operation and maintenance, and D
carefully reading and understanding the contents of
this manual. If you have any questions about these
instructions contact your Emerson Process
Management sales office before proceeding.
Figure 1. Fisher GX Control Valve, Actuator, and
FIELDVUE DVC2000 Series Digital Valve Controller
W8861
Description
The GX is a compact, state-of-the-art control valve
and actuator system, designed to control a wide
range of process gases, vapors, and fluids.
The GX is rugged, reliable, and easy to select. It
requires no actuator sizing -- the actuator selection
is automatic once the valve body construction is
selected.
The GX meets the requirements of both EN and
ASME standards. It is available with a complete
accessory package, including the FIELDVUE
DVC2000 Series integrated digital valve controller.
Instruction Manual
D103175X012
February 2009 GX Valve and Actuator

GX Valve and Actuator
Instruction Manual
February 2009
2
Table 1. Fisher GX Valve Specifications
Specifications EN ASME
Valve Body Size DN 15, 20, 25, 40, 50, 80, 100, 150 NPS 1/2, 3/4, 1, 1-1/2, 2, 3, 4, and 6
Pressure Rating PN 10 / 16 / 25 / 40 per EN 1092-1 CL150 / 300 per ASME B16.34
End Connections Flanged raised face per EN 1092-1 Flanged raised face per ASME B16.5
Valve Body/Bonnet
Materials
1.0619 steel ASME SA216 WCC steel
1.4409 stainless steel ASME SA351 CF3M stainless steel
CW2M (sizes DN 25 through DN 100 only) CW2M (NPS 1 through 4 only)
ASME SA352 LCC ASME SA352 LCC
Face-to-Face Dimensions Consistent with EN 558-1 Series 1 Consistent with ANSI/ISA 75.08.01
Shutoff per IEC 60534-4
and ANSI/FCI 70-2
Metal seat - Class IV (standard)
Metal seat - Class V (optional)
PTFE seat - Class VI (optional)(1)
Flow Direction Flow-up (CavitroltIII cage, Flow down)
Flow Control Characteristics Equal Percentage and Linear
Trim Style
Port Diameters Trim Style Description
4.8 mm Micro-Flow trim (unbalanced)
9.5, 14, 22 mm Stem-Guided with Contoured Plug (unbalanced)
or Port-Guided with Cavitrol III trim (unbalanced)
36, 46 mm Port-Guided Plug (unbalanced)
70, 90, 136 mm Balanced Trim with Contoured plug (standard) or Unbalanced Port-Guided
Plug (optional)
Handwheel Available as an option
Travel Stop Available as an option
1. For 4.8 to 14 mm ports, Class VI shutoff is achieved without PTFE seat.
Valve Installation
WARNING
Always wear protective gloves,
clothing, and eyewear when
performing any installation operations
to avoid personal injury.
Personal injury or equipment damage
caused by sudden release of pressure
or bursting of pressure retaining parts
might result if service conditions
exceed those for which the product
was intended. To avoid injury or
damage, provide a relief valve for over
pressure protection as required by
government or accepted industry
codes and good engineering practices.
Check with your process or safety
engineer for any additional measures
that must be taken to protect against
process media.
If installing into an existing
application, also refer to the WARNING
at the beginning of the Maintenance
section in this instruction manual.
CAUTION
This valve is intended for a specific
range of pressures, temperatures and
other application specifications.
Applying different pressure and
temperatures to the valve could result
in parts damage, malfunction of the
control valve or loss of control of the
process. Do not expose this product to
service conditions or variables other
than those for which the product was
intended. If you are not sure what
these conditions are you should
contact your Emerson Process
Management sales office for more
complete specifications. Provide the
product serial number (shown on the
nameplate, figure 2) and all other
pertinent information.
WARNING
If you move or work on an actuator
installed on a valve with loading
pressure applied, keep your hands and
tools away from the stem travel path to

GX Valve and Actuator
Instruction Manual
February 2009
3
Figure 2. Fisher GX Nameplate Examples
GE01296-99
WITH SPRING INFORMATION
WITHOUT SPRING INFORMATION
GE01296-G
avoid personal injury. Be especially
careful when removing the stem
connector to release all loading on the
actuator stem whether it be from air
pressure on the diaphragm or
compression in the actuator springs.
Likewise take similar care when
adjusting or removing any optional
travel stop. Refer to the relevant
actuator Maintenance Instructions.
If hoisting the valve take care to
prevent people from being injured in
case the hoist or rigging slips. Be sure
to use adequately sized hoists and
chains or slings to handle the valve.
1. Before installing the valve, inspect it to be certain
that the valve body cavity is free of all foreign
material. Clean out all pipelines to remove scale,
welding slag and other foreign material.
2. The control valve assembly may be installed in
any orientation unless limited by seismic criteria.
However, the normal method is with the actuator
vertical above the valve. Flow through the valve
must be in the direction indicated by the arrow cast
on the valve.
3. Use accepted piping practices when installing the
valve in the pipeline. Use a suitable gasket between
the valve and the pipeline flanges.
4. If continuous operation is required during
inspection or maintenance, install isolating valves on
either side of the control valve with a bypass valve to
control the flow while the control valve is receiving
maintenance.
WARNING
Personal injury could result from
packing leakage. Valve packing is
tightened before shipment; however
the packing might require some
readjustment to meet specific service
conditions.
Maintenance
WARNING
Avoid personal injury or property
damage from sudden release of
process pressure or bursting of parts.
Before performing any maintenance
operations:
DDo not remove the actuator from
the valve while the valve is still
pressurized.
DAlways wear protective gloves,
clothing, and eyewear when
performing any maintenance
operations to avoid personal injury.
DDisconnect any operating lines
providing air pressure, electric power
or a control signal to the actuator. Be
sure the actuator cannot suddenly
open or close the valve.
DUse bypass valves or completely
shut off the process to isolate the
valve from the process pressure.
Relieve the process pressure from
both sides of the valve.
DDepending on the actuator
construction, it will be necessary to
manage the pneumatic actuator
loading pressure and any actuator
spring pre-compression. It is essential
to refer to the relevant actuator

GX Valve and Actuator
Instruction Manual
February 2009
4
instructions in this manual to ensure
safe removal of the actuator from the
valve.
DUse lock-out procedures to be
sure that the above measures stay in
effect while you work on the
equipment.
DThe valve packing box may
contain process fluids that are
pressurized, even when the valve has
been removed from the pipeline.
Process fluids may spray out under
pressure when removing the packing
hardware or packing rings, or when
loosening the packing box pipe plug.
DCheck with your process or safety
engineer for any additional measures
that must be taken to protect against
process media.
Note
Whenever a gasket seal is disturbed
by removing or shifting gasketed
parts, install a new gasket during
reassembly. This ensures a good
gasket seal because the used gasket
may not seal properly.
Actuator Maintenance
The following sections provide procedures for
actuator maintenance. Refer to figures 18, 19, 20,
and 21.
The actuator soft parts may require periodic
replacement. This includes the diaphragm (key 10),
actuator rod bushing (key 19), and the actuator rod
seal (key 20).
If the actuator stroking direction (air-to-open or
air-to-close) is unknown, refer to the nameplate on
top of the actuator casing and figure 2.
There are several optional actuator constructions,
depending on supply pressure. Refer to the
nameplate on the top of the actuator to determine
the construction installed. Refer to figure 3 and
table 2 for proper spring configuration.
Note
Older GX actuator nameplates do not
contain spring configuration
information. If you require replacement
springs or wish to switch to an
optional actuator construction, consult
your Emerson Process Management
sales office.
Note
When the GX actuator is equipped with
the integrated FIELDVUE DVC2000
Series digital valve controller (figure
1), additional considerations may be
required. Refer to the FIELDVUE
DVC2000 Digital Valve Controller
Mounting section of this manual for
additional instruction.
Actuator Disassembly (For Air-to-Open
Constructions - see figures 18 or 19)
1. Connect a separate air supply to the lower
diaphragm casing via the air supply connection on
the yoke (as shown in figure 18 or 19) and apply
sufficient air pressure to raise the valve plug/stem off
the seat to mid-travel.
2. Remove the stem connector nut half (key 23),
stem connector bolt half (key 24), and travel
indicator (key 26).
3. Push the valve plug/stem (key 3) down until it
contacts the seat.
4. Loosen the locknut (key 28) and thread the stem
adjustor nut (key 27) down until it clears the top of
the valve plug/stem (key 3).
5. Shut off the air pressure and disconnect the
separate air supply to the lower diaphragm casing
(as shown in figure 18 or 19).
WARNING
To avoid personal injury or property
damage due to actuator springs (keys
12 and 82) being under compression,
remove the long cap screws (key 16)
last.
The upper actuator casing may remain
fixed to the diaphragm and lower
casing during disassembly, even if the
casing cap screws have been
loosened. If this happens, the actuator

GX Valve and Actuator
Instruction Manual
February 2009
5
springs are still under compression.
The upper casing could suddenly
come loose and jump, due to the
compressed energy of the springs. If
the upper casing is stuck to the
diaphragm and lower casing when you
begin loosening the casing cap
screws, pry the casings apart with a
prying tool. Always ensure that the
springs are dispersing energy and the
upper casing is moving against the
long bolts during disassembly.
6. Remove the short actuator casing cap screws
and hex nuts (keys 17 and 18) first. Once these
have been removed from the actuator assembly,
carefully remove the long actuator cap screws and
hex nuts (keys 16 and 18), alternating between them
to gradually release the spring energy
(compression).
7. Remove the upper diaphragm casing (key 9) and
the actuator springs (key 12 and/or 82).
8. Lift off the actuator stem/diaphragm assembly
(includes keys 22, 11, 10, 14, 13, and 15) and
remove the cap screw (key 14), actuator spacer
(key 13), actuator rod (key 22), and washer (key 15).
9. Replace the diaphragm (key 10), actuator rod
bushing (key 19), and actuator rod seal (key 20), as
needed.
Actuator Disassembly (For Air-to-Close
Constructions - see figure 20 or 21)
1. Remove the stem connector nut half (key 23),
stem connector bolt half (key 24), and travel
indicator (key 26).
WARNING
To avoid personal injury or property
damage due to actuator springs (key
12) being under compression, remove
the long cap screws (key 16) last.
The upper actuator casing may remain
fixed to the diaphragm and lower
casing during disassembly, even if the
casing cap screws have been
loosened. If this happens, the actuator
springs are still under compression.
The upper casing could suddenly
come loose and jump, due to the
compressed energy of the springs. If
the upper casing is stuck to the
diaphragm and lower casing when you
begin loosening the casing cap
screws, pry the casings apart with a
prying tool. Always ensure that the
springs are dispersing energy and the
upper casing is moving against the
long bolts during disassembly.
2. Remove the short actuator casing cap screws
and hex nuts (keys 17 and 18) first. Once these
have been removed from the actuator assembly,
carefully remove the long actuator cap screws and
hex nuts (keys 16 and 18), alternating between them
to gradually release the spring energy
(compression).
3. Remove the upper diaphragm casing (key 9).
4. Lift off the actuator stem/diaphragm assembly
(includes keys 22, 11, 10, 14, 13, and 15) and
remove the cap screw (key 14), actuator spacer
(key 13), actuator rod (key 22), and washer (key 15).
5. Remove the actuator springs (key 12 and/or 82).
6. Replace the diaphragm (key 10), actuator rod
bushing (key 19), and actuator rod seal (key 20), as
needed.

GX Valve and Actuator
Instruction Manual
February 2009
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GG00398-A
Figure 3. Spring Configuration

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Instruction Manual
February 2009
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Table 2. Actuator Spring Configuration Based on Minimum Supply Pressure(1)
ACTUATOR SIZE TRAVEL STEM MATERIAL MINIMUM SUPPLY
PRESSURE
SPRING CONFIGURATION
mm Air-to-Open Air-to-Close
225 20 S20910, N05500
S31603
4 bar (58 psi) A6 A3
3 bar (44 psi) A4 A3
2 bar (29 psi) A3 A2
225 20 S31803, N10665,
N06022
4 bar (58 psi) A6 A3
3 bar (44 psi) A4 A3
2 bar (29 psi) A3 A2
750 20 S20910, N05500
S31603
4 bar (58 psi) B6 B4
3 bar (44 psi) B6 B4
2 bar (29 psi) B4 B4
750 20 S31803, N10665,
N06022
4 bar (58 psi) B4 B4
3 bar (44 psi) B4 B4
2 bar (29 psi) B4 B4
750 40 S20910, N05500
S31603
4 bar (58 psi) C12 C6
3 bar (44 psi) C8 C3
2 bar (29 psi) C4 C3
750 40 S31803, N10665,
N06022
4 bar (58 psi) C8 C6
3 bar (44 psi) C8 C3
2 bar (29 psi) C4 C3
1200 40 or 60 S20910, N05500
S31603
4 bar (58 psi) D15 D15
3 bar (44 psi) D15 D15
2 bar (29 psi) N/A N/A
1. Only applicable to actuators with spring information on the nameplate (see figure 2).
Table 3. Fisher GX Maximum Rated Travel
ACTUATOR SIZE NUMBER OF
CASING BOLTS
TRAVEL
mm
225 6 20
750 10 20 or 40
1200 16 40 or 60
Table 4. Body Nut (Key 7) Torque Requirements
VALVE SIZE TORQUE
NSm lbfSft
DN 15, 20, 25
(NPS 1/2, 3/4, 1) 38.2 28.2
DN 40 and DN 50
(NPS 1-1/2 and 2) 65.5 48.3
DN 80 (NPS 3) 157 116
DN 100 and DN 150
(NPS 4 and 6) 284 209
Table 5. Yoke/Extension Bonnet Nut (Key 46) Torque
Requirements (used on Extension Bonnet and Bellows
Bonnet constructions)
VALVE SIZE TORQUE
NSm lbfSft
DN 15, 20, 25, 40,
and 50 (NPS 1/2,
3/4, 1, 1-1/2, and 2)
65.5 48.3
DN 80 and 100
(NPS 3 and 4) 157 116
Actuator Assembly For Air-to-Open
Constructions (or to Change Action to
Air-to-Open - see figure 18 or 19)
1. Install the diaphragm (key 10) on the diaphragm
plate (key 11). Insert the cap screw (key 14) through
the actuator spacer (key 13) and place this assembly
through the diaphragm/diaphragm plate assembly.
2. Place the washer (key 15) over the center hole of
the diaphragm, so that the convex part of the washer
is facing down toward the diaphragm.
3. Screw the actuator rod (key 22) onto the cap
screw (key 14) and torque to 65.5 NSm (48.3 lbfSft).
Install the actuator stem/diaphragm assembly back
into the actuator yoke (key 8).
4. Place the actuator springs (key 12 and/or 82)
onto the spring locators in the diaphragm plate
(key 11). See figure 3 and table 2 for proper spring
quantity and arrangement.
DIf the nameplate does not contain spring
information, use the same quantity and arrangement
as originally installed.
5. Install the upper diaphragm casing (key 9) so that
the ribs on the top of the upper diaphragm casing
are perpendicular with the yoke legs.

GX Valve and Actuator
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February 2009
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DFor size 225 and 750 actuators, install the 2
long cap screws (key 16) and hex nuts (key 18) 180
degrees apart from each other and in line with the
actuator yoke legs.
DFor size 1200 actuators, install the 4long cap
screws (key 16) and hex nuts (key 18) 90 degrees
from each other, with two of them in line with the
actuator yoke legs.
6. Tighten the long cap screws (key 16) and hex
nuts (key 18), alternating between them to gradually
compress the springs, until the two casing halves
and diaphragm touch.
7. Install the remaining short cap screws (key 17)
and hex nuts (key 18) to the casing.
8. Tighten the actuator casing cap screws evenly
using a cross-tightening procedure. Torque to 55
NSm (40 lbfSft).
9. If you had previously removed the actuator
assembly from the valve, place the actuator
assembly back onto the valve body (key 1). Install
the four body nuts (key 7), but tighten them only
finger-tight.
10. Connect a separate air supply to the actuator air
supply connection (as shown on the yoke in figure
18 or 19) and apply sufficient air pressure to raise
the actuator rod (key 22) to the travel stop.
Note: If converting from air-to-close to
air-to-open action, first move the vent cap
(key 21) from the air supply connection on the
yoke leg (see figure 20 or 21) to the top of the
casing (see figure 18 or 19).
11. For standard bonnet constructions
(figures 18, 19, 20, and 21), tighten the body nuts
(key 7) evenly using a cross-tightening procedure.
See table 4 for torque requirements.
For extension and bellows bonnet constructions
(figures 22 and 23), tighten the bonnet nuts
(key 46) evenly using a cross-tightening procedure.
See table 5 for torque requirements.
12. With the valve plug/stem (key 3) on the seat,
thread the stem adjustor nut (key 27) up until it is the
rated travel distance specified in table 3 from the
actuator rod (key 22). Thread the locknut (key 28) up
against the stem locknut and tighten per table 6.
Table 6. Stem Connector Torque Values
PART STEM
MATERIAL
TORQUE
NSm LbfSft
M8 Stem
Connector
Cap Screws
All 35 26
M10 Stem
Connector
Jam Nut (Rie
4606 Coated)
S31603,
S20910,
N05500
48 35
N06022,
S31803,
N10665
35 26
M14 Stem
Connector
Jam Nut
S31603,
S20910,
N05500
175 129
N06022,
S31803,
N10665
138 102
13. Stroke the actuator rod until it contacts the stem
adjuster nut (key 27) and install the stem connector
halves and travel indicator (keys 23, 24, and 26) with
the cap screws (key 25). Install the stem connector
halves in the proper orientation so that when looking
at the inside of the stem connector halves, the flats
are down and the beveled surfaces are up.
14. Align the pointer of the travel indicator (key 26)
with the appropriate mark on the travel scale.
15. Tighten the stem connector cap screws
(key 25) to 35 NSm (26 lbfSft).
16. Release the actuator pressure.
17. Note: For air-to-open action, the air supply
tubing must be connected to the actuator yoke at
the air supply connection, see figure 18 or 19. (If
converting from air-to-close to air-to-open, the
tubing will need to be re-routed to this location).
Actuator Assembly For Air-to-Close
Constructions (or to Change Action to
Air-to-Close - see figure 20 or 21)
1. Position the upper diaphragm casing (key 9)
upside down on the bench so that it lays flat and not
off balance.
Note: If converting from air-to-open to
air-to-close action, first move the vent cap
(key 21) from the top of the casing (see figure 18
or 19) and thread into the air supply connection
on the yoke leg (see figure 20 or 21).
2. Install the diaphragm (key 10) on the diaphragm
plate (key 11). Place the washer (key 15) over the
center hole of the diaphragm, so that the convex part
of the washer is facing down toward the diaphragm.
3. Insert the cap screw (key 14) through the washer
and diaphragm, install the actuator spacer (key 13),

GX Valve and Actuator
Instruction Manual
February 2009
9
and screw the actuator rod (key 22) onto the cap
screw (key 14) finger-tight.
4. Radially align the spring locators in the
diaphragm plate assembly (key 11) with the casing
cap screw holes in the diaphragm (key 10). This will
ensure that the springs do not cover the air path in
the yoke.
5. Torque the cap screw (key 14) to the actuator rod
(key 22) to 65.5 NSm (48.3 lbfSft) and lay this
assembly into the upper diaphragm casing (key 9).
6. Place the actuator springs (key 12 and/or 82)
onto the spring locators in the diaphragm plate
(key 11). See figure 3 and table 2 for proper spring
quantity and arrangement.
DIf the nameplate does not contain spring
information, use the same quantity and arrangement
as originally installed.
7. Remove and replace the actuator rod bushing
(key 19) and actuator rod seal (key 20) in the
actuator yoke (key 8), if necessary.
8. Set the actuator yoke (key 8) down onto the
assembly that is resting in the upper diaphragm
casing (key 9) so that the yoke legs are
perpendicular with the ribs on the top of the upper
diaphragm casing (key 9).
DFor size 225 and 750 actuators, install the 2
long cap screws (key 16) and hex nuts (key 18) 180
degrees apart from each other and in line with the
actuator yoke legs.
DFor size 1200 actuators, install the 4long cap
screws (key 16) and hex nuts (key 18) 90 degrees
from each other, with two of them in line with the
actuator yoke legs.
9. Tighten the long cap screws (key 16) and hex
nuts (key 18), alternating between them to gradually
compress the springs, until the two casing halves
and diaphragm touch.
10. Install the remaining short cap screws (key 17)
and hex nuts (key 18) to the casing.
11. Tighten the actuator casing cap screws evenly
using a cross-tightening procedure. Torque to 55
NSm (40 lbfSft).
12. If you had previously removed the actuator
assembly from the valve, place the actuator
assembly back onto the valve body (key 1). For
standard bonnet constructions (figures 18, 19,
20, and 21), install the body nuts (key 7) and tighten
evenly using a cross-tightening procedure.
See table 4 for torque requirements.
For extension and bellows bonnet constructions
(figures 22 and 23), install the bonnet nuts (key 46)
and tighten evenly using a cross-tightening
procedure. See table 5 for torque requirements.
13. With the valve plug/stem (key 3) in the closed
position (on the seat), thread the stem adjustor nut
(key 27) up until it is at the rated travel (see table 3)
from the actuator rod (key 22). Thread the locknut
(key 28) up against the stem locknut and tighten per
table 6.
14. Stroke the actuator rod until it contacts the stem
adjuster nut (key 27) and install the stem connector
halves and travel indicator (keys 23, 24, and 26) with
the cap screws (key 25). Install the stem connector
halves in the proper orientation so that when looking
at the inside of the stem connector halves, the flats
are down and the beveled surfaces are up.
15. Align the pointer of the travel indicator (key 26)
with the appropriate mark on the travel scale.
16. Tighten the stem connector cap screws
(key 25) to 35 NSm (26 lbfSft).
17. Note: For air-to-close action, the air supply
tubing must be connected to the actuator upper
casing at the air supply connection, see
figure 20 or 21. (If converting from air-to-open to
air-to-close, the tubing will need to be re-routed
to this location).
FIELDVUE DVC2000 Digital Valve
Controller Mounting
This section provides instruction on mounting the
FIELDVUE DVC2000 Series digital valve controller
to the GX control valve. For further detail on the
operation and maintenance of the DVC2000, refer to
the DVC2000 instruction manual.
The FIELDVUE DVC2000 Series digital valve
controller mounts directly to an interface pad on the
GX actuator yoke leg, eliminating the need for
mounting brackets (see figure 1). Internal
passageways in the actuator route the pneumatic
output to the actuator casing, which eliminates the
need for external air supply tubing in the air-to-open
(spring-to-close) constructions. (The GX will also
accommodate other valve positioners, using the
NAMUR mounting pads on the side of the yoke
legs.)

GX Valve and Actuator
Instruction Manual
February 2009
10
POLE PIECES
M8 MOUNTING BOLTS
A: EXTERNAL PNEUMATIC
OUTPUT PORT (1/4 NPT
OR G1/4 PLUG)
B: INTEGRAL MOUNTING
PNEUMATIC OUTPUT
PORT (R1/8 PLUG)
FOR AIR-TO-OPEN, INSTALL THE O-RING SEAL
BEFORE MOUNTING TO THE GX ACTUATOR
Figure 4. DVC2000 Digital Valve Controller Mounting Details
The DVC2000 features linkage-less position
feedback when mounted to the GX control valve.
There are no touching parts between the controller
and the valve stem, which simplifies controller
installation. If maintenance is required, the DVC2000
can be easily removed from the valve.
In the air-to-open (spring-to-close) configuration, the
air signal to the actuator casing is supplied through
the air supply connection on the GX actuator yoke
leg (see figure 18 or 19). In the air-to-close
(spring-to-open) configuration, the air signal is
supplied to the actuator through the air supply
connection on the top of the actuator casing (see
figure 20 or 21).
For an air-to-open construction, a DVC2000 will
mount to the actuator (figure 18 or 19). The air signal
is transmitted to the lower casing through the
pneumatic passageway marked “air supply
connection” in figure 18 or 19.
For an air-to-close construction, DN 15 through
DN 100 (NPS 1/2 through 4) only: in the actuator
design (figure 20 or 21), the pneumatic signal is
connected directly to the air supply connection in the
upper actuator casing. The yoke is symmetrical and
the air passageways serve as a vent, whereby the
DVC2000 can be easily moved from one side of the
valve to the other without rotating the actuator.
DVC2000 Mounting Procedures
Steps A and B of the following instructions apply to
the actuator construction shown in figures 18, 19,
20, and 21.
A. Mounting the DVC2000 to an air-to-open GX
actuator (spring-to-close) (see figure 4 and figure
18 or 19):
1. Attach the magnetic feedback array (supplied
with the DVC2000) to the valve stem connector
using the alignment template (supplied with the
mounting kit) for accurate alignment.
2. Remove the plug (R1/8) from the back of the
DVC2000 housing (Port B in figure 4). This
pneumatic output port on the DVC2000 lines up with
the integral GX actuator air supply connection (see
figure 18 or 19).
3. Install the plug (either G1/4 or 1/4 NPT, included
in the mounting kit) to the external output pneumatic
port (Port A in figure 4).
4. Remove the digital valve controller’s cover.
5. Using a 6mm hex wrench, attach the digital valve
controller to the GX actuator mounting pad on the
side that has the open pneumatic port. Be sure to
place the O-ring seal between the digital valve
controller’s pneumatic output and the actuator
mounting pad (Port B, as shown in figure 4).

GX Valve and Actuator
Instruction Manual
February 2009
11
Pneumatic tubing is not required because the air
passages are internal to the actuator. Also, install
the insulating gaskets around the mounting bolts.
6. Check for clearance between the magnet
assembly and the DVC2000 feedback slot. The
magnet assembly should be positioned such that the
index mark in the feedback slot of the DVC2000
housing is between the valid range on the magnet
assembly throughout the range of travel.
(See figure 4).
B. For air-to-close GX actuator (spring-to-open)
(see figure 4 and figure 20 or 21):
1. Attach the magnetic feedback array (supplied
with the DVC2000) to the valve stem connector
using the alignment template (supplied with the
mounting kit) for accurate alignment.
2. In the air-to-close configuration it is required that
an R1/8 plug be installed into the integral mount
pneumatic port on the back of the DVC2000 housing
(Port B of figure 4).
3. Remove the digital valve controller’s cover.
4. Using a 6mm hex wrench, attach the digital valve
controller to the GX actuator mounting pad.
Note
The O-ring seal and G1/4 or 1/4 NPT
plugs (supplied in the mounting kit)
are not used with this actuator
construction.
5. Check for clearance between the magnet
assembly and the DVC2000 feedback slot. The
magnet assembly should be positioned such that the
index mark on the pole pieces (back of the controller
housing) is between the marks on the magnet
assembly throughout the range of travel. (See
figure 4.)
6. Install tubing between the external pneumatic
output connection of the DVC2000 (Port A of
figure 4) to the air supply connection (see figure 20
or 21) on top of the actuator casing.
When changing actuator action:
When field converting a GX actuator from
air-to-open to air-to-close closed (or vice-versa), you
will need to change the plugs for the pneumatic
passages in the DVC2000 housing.
DTo convert from air-to-close to air-to-open
(spring-to-close), remove the R1/8 pneumatic plug
on the back of the DVC2000 housing and install an
O-ring (Port B of figure 4). Plug the external
pneumatic output with a 1/4 NPT or G1/4 plug
(depending on the housing version). (Port A of
figure 4.)
DTo convert from air-to-open to air-to-close
(spring-to-open), remove the external pneumatic
plug (1/4 NPT or G1/4 plug, depending on the
housing version from Port A of figure 4). Install an
R1/8 plug on the back of the DVC2000 housing (Port
B of figure 4). Install tubing between the pneumatic
output connection of the DVC2000 (Port A) to the air
supply connection on top of the actuator casing (see
figure 20 or 21).
Packing Maintenance
Key numbers refer to figures 15, 18, 19, 20, 21, 22,
and 23.
Packing Adjustment
For spring-loaded single PTFE V-ring packing
(figure 15) or for Graphite ULF packing (figure 16),
the Belleville spring pack (key 34) maintains a
sealing force on the packing. If leakage is detected
around the packing follower (key 29) check to be
sure that the packing follower (key 29) is tight. Using
a wrench, tighten the packing follower (key 29) in 1/4
turn intervals until the leakage is stopped. If leakage
cannot be stopped in this manner, proceed to the
Replacing Packing section in this manual.
Replacing Packing
This section provides instruction on replacing
packing in standard bonnets, extension bonnets, and
bellows extension bonnets.
Isolate the control valve from the line pressure,
release pressure from both sides of the valve body
and drain the process media from both sides of the
valve. Shut off all pressure lines to the actuator and
release all pressure from the actuator. Use lock-out
procedures to ensure that the above measures stay
in effect while you work on the equipment.
1. For air-to-open constructions:
a. Connect a separate air supply to the lower
diaphragm casing via the air supply connection
on the yoke (as shown in figure 18 or 19) and
apply sufficient air pressure to raise the valve
plug/stem off the seat to mid travel.

GX Valve and Actuator
Instruction Manual
February 2009
12
b. Remove the stem connector nut half (key 23),
stem connector bolt half (key 24), and travel
indicator (key 26).
c. Push the valve plug stem (key 3) down until it
contacts the seat.
d. Loosen the locknut (key 28) and thread the
stem adjustor nut (key 27) down until it clears the
top of the valve plug stem (key 3).
e. Shut off the air pressure and disconnect the
separate air supply to the lower diaphragm
casing (as shown in figure 18 or 19).
2. For air-to-close constructions, as shown in
figure 20 or 21, remove the stem connector nut half
(key 23), stem connector bolt half (key 24), and
travel indicator (key 26).
WARNING
To avoid personal injury or property
damage by uncontrolled movement of
the actuator yoke (key 8), loosen the
body/yoke nuts (figures 18, 19, 20, and
21, key 7) or bonnet/yoke nuts (figures
22 and 23, key 46) by following the
instructions in the next step. Do not
remove a stuck actuator yoke by
pulling on it with equipment that can
stretch or store energy in any other
manner. The sudden release of stored
energy can cause uncontrolled
movement of the actuator yoke.
Note
The following step also provides
additional assurance that the valve
body fluid pressure has been relieved.
3. For standard bonnet constructions (figures
18, 19, 20, and 21), body nuts (key 7) attach the
actuator yoke (key 8) to the valve body (key 1).
Loosen these nuts approximately 3mm (1/8 inch).
For extension and bellows bonnet constructions,
bonnet nuts (key 46) attach the actuator yoke (key 8)
to the extension bonnet (key 39). Loosen these nuts
approximately 3mm (1/8 inch).
4. Then loosen the valve-to-yoke gasketed joint by
either rocking the actuator yoke or prying between
the valve and actuator yoke. Work the prying tool
around the actuator yoke until it loosens.
WARNING
If there is evidence of process fluid
under pressure leaking from the joint,
retighten the valve body/joint nuts and
return to the Warning at the beginning
of the Maintenance section to ensure
proper steps have been taken to
isolate the valve and relieve process
pressure.
5. If no fluid leaks from the joint, loosen the packing
follower (key 29) two turns to relieve the packing
compression load.
6. For standard bonnet constructions (figures
18, 19, 20, and 21), remove the body nuts (key 7)
completely.
For extension and bellows bonnet constructions
(figures 22 and 23), remove the bonnet nuts
(key 46) completely.
CAUTION
To avoid property damage, place the
actuator yoke on a protective surface,
as described in the following
procedure.
7. Carefully lift off the actuator yoke and set it on a
protective surface to prevent damage.
For standard bonnet constructions, if the bonnet
(key 4) together with the valve stem plug assembly
has a tendency to lift with the actuator yoke, ensure
it does not drop from the actuator.
For extension and bellows constructions, ensure
the bonnet (key 4) does not lift with the actuator
yoke.
For DN150 balanced constructions, if the bonnet,
guide sleeve, or valve stem assembly have a
tendency to lift with the actuator yoke, ensure they
do not drop from the actuator.

GX Valve and Actuator
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13
GE02918-6
AA
G
B
B
H
DF
E
CC
C
DF
E
DN15, 20, 25
(NPS 1/2, 3/4, 1)
DN40, 50, 80, 100
(NPS 1-1/2, 2, 3, 4)
A
B
E
F
C
C
J
KD
DN150
(NPS 6)
DN25 Cav III
(NPS 1)
GG01215
C
OF
OG
D
E
H
B
A
Figure 5. Seat Ring Removal and Installation Tool
Table 7. Seat Ring Removal and Installation Tool Dimensions
Valve Size A B C D E FOGOHJOK
DN NPS mm
15, 20, 25 1/2, 3/4, 1 24 15 15.2 9 54 40 45 10 - - - - - -
25 (Cavitrol III) 1 (Cavitrol III) 24 18 13 6 30 39 45 10 - - - - - -
40(1) 1-1/2(1) 36 20 2X 13.2 7.5 58 53 - - - - - - - - - - - -
50(1) 2(1) 46 28 2X 13.2 7.5 63 63 - - - - - - - - - - - -
80 3 60 36 2X 15.2 8.5 100 93 - - - - - - - - - - - -
100 4 70 44 2X 17.2 9.5 114 113 - - - - - - - - - - - -
150 6 100 50 2X 43 10.5 170.5 174 - - - - - - 153 20
1. Also used for Cavitrol III cage removal.
CAUTION
For extension and bellows bonnet
constructions, lifting the bonnet with
the actuator yoke may cause possible
damage to the valve plug and to the
bellows.
8. Remove the stem adjustor nut (key 27) and
locknut (key 28).
9. For standard bonnet constructions, remove
the bonnet and the valve plug/stem assembly and
set on a protective surface.
For extension and bellows bonnet constructions,
remove only the bonnet (key 4).
For DN150 balanced constructions, remove the
guide sleeve, bonnet, and valve plug stem
assembly.

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14
Table 8. Packing Follower Torque
Valve Size Packing
Style
Torque
NSm
(lbfSft)
Packing
Style
Torque
NSm
(lbfSft)
DN15, 20,
25, 40, and
50
PTFE 10 (7.4) ULF 35 (26)
DN80 and
100 PTFE 23 (17) ULF 50 (37)
DN150 PTFE 36 (26) ULF 68 (50)
10. Remove the valve/yoke gasket
(figures 18, 19, 20, and 21 key 5, figures 22 and 23
key 47) and cover the opening of the valve to protect
the gasket surface and prevent foreign matter from
getting into the valve cavity.
11. Remove the packing follower (key 29) from the
bonnet (key 4).
12. Remove the Belleville spring pack (key 34) and
packing spacer (key 30) from the bonnet (key 4).
Carefully push out the remaining packing box parts
from the bonnet (key 4) using a rounded rod or other
tool which will not scratch the packing box wall.
Clean the packing box and the metal packing box
parts.
CAUTION
Inspect the valve stem, threads and
packing box surfaces for any sharp
edges that might cut the packing.
Scratches or burrs could cause
packing box leakage or damage the
new packing.
13. Inspect the valve stem, threads and packing box
surfaces for any sharp edges that might cut the
packing. Scratches or burrs could cause packing box
leakage or damage the new packing. If the surface
condition cannot be improved by light sanding,
replace the damaged parts.
14. Remove the covering protecting the valve
cavity and install a new valve/yoke gasket
(figures 18, 19, 20, and 21 key 5, figures 22 and 23
key 47) making sure that the gasket seating surfaces
are clean and smooth.
For DN150 balanced constructions, two gaskets
are required; one between the valve body and guide
sleeve, and the other between the guide sleeve and
bonnet. Ensure the gasket seating surfaces are
clean and smooth for both gaskets.
15. Carefully install the bonnet (key 4) onto the
valve stem.
16. Install the new packing and the metal packing
box parts according to figure 15 for PTFE packing
and according to figure 16 for Graphite ULF packing.
Place a smooth-edged pipe over the valve stem and
gently tap each soft packing part into the packing
box. Apply anti-seize lubricant to the threads and
install the packing follower (key 29).
17. Install the locknut (key 28) and stem adjustor
nut (key 27).
For standard bonnet constructions, install the
valve plug/bonnet sub assembly into the valve body
(key 1).
18. Mount the actuator onto the valve and install the
body nuts (figures 18, 19, 20, 21 key 7, figures 22
and 23 key 46), but tighten them only finger-tight.
19. For air-to-open, connect a separate air supply
to the lower diaphragm casing air supply connection
(as shown in figure 18 or 19) and apply sufficient air
pressure to raise the actuator rod (key 22) to the
travel stop. Proceed to the next step.
For air-to-close, proceed to the next step.
20. For standard bonnet constructions, tighten
the body nuts (key 7) evenly using a cross-tightening
procedure. See table 4 for torque requirements.
For extension and bellows bonnet constructions,
tighten the bonnet nuts (key 46) evenly using a
cross-tightening procedure. See table 5 for torque
requirements.
21. Thread the stem lock adjustor (key 27) up until it
is the rated travel distance specified in table 3 from
the actuator rod (key 22). Thread the locknut
(key 28) up against the stem locknut and tighten to a
torque of 55 NSm (40 lbfSft) for 10mm stems or 148
NSm (110 lbfSft) for both 14mm and 19mm stems.
22. Stroke the actuator rod until it contacts the stem
adjuster nut (key 27) and install the stem connector
halves and travel indicator (keys 23, 24, and 26) with
the cap screws (key 25). Install the stem connector
halves in the proper orientation so that when looking
at the inside of the stem connector halves, the flats
are down and the beveled surfaces are up.
23. Align the pointer of the travel indicator (key 26)
with the appropriate mark on the travel scale.
24. Tighten the stem connector cap screws (key 25)
to 35 Nxm (26 lbfxft).

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15
Table 9. Seat Ring / Cage Torque Requirements
VALVE SIZE TORQUE
DN NPS NSm lbfSft
15, 20, 25 1/2, 3/4, 1 170 124
40 1-1/2 320 234
50 2 460 337
80 3 1020 747
100 4 1520 1113
150 6 3400 2500
Table 10. Stem Extension Torque Requirements
VALVE SIZE TORQUE
DN NPS Nxm Lbfxft
15, 20, 25, 40, 50 1/2, 3/4, 1, 1-1/2, 2 40 30
80, 100 3, 4 120 89
Table 11. Bellows Nut Torque Requirements
VALVE SIZE TORQUE
DN NPS Nxm Lbfxft
15, 20, 25, 40, 50 1/2, 3/4, 1, 1-1/2, 2 350 260
80, 100 3, 4 650 480
25. Tighten the packing follower (key 29) to the
torque specified in table 8.
Alternately, the packing follower can be tightened by
the following method:
a. Tighten the packing follower until the Belleville
springs are compressed 100% (or completely
flat), as detected by a rapid increase in nut
torque.
b. For DN 15 through DN 100 (NPS 1/2
through 4), loosen the packing follower 60_of
rotation.
For DN 150 (NPS 6), loosen the packing follower
90_of rotation.
26. For air-to-open, release the actuator pressure.
27. For air-to-open, ensure the vent (key 21) is
installed into the upper diaphragm casing
(see figure 18 or 19).
For air-to-close, ensure the vent (key 21) is
installed into the actuator yoke air supply connection
(see figure 20 or 21).
Valve Trim Maintenance
Key numbers in this section refer to figures 18, 19,
20, 21, 22, and 23.
Valve Trim Disassembly
1. Remove the actuator and bonnet assembly as
described in the Replacing Packing section (steps 1
through 10).
DFor standard bonnet constructions
(figures 18, 19, 20, 21, and 25), proceed to the
Seat Ring / Cage Removal section.
DFor extension bonnet constructions
(figure 22), proceed to step 3.
DFor bellows bonnet constructions
(figure 23), proceed to step 2.
2. For bellows bonnet constructions (figure 23),
use a bellows nut tool made according to the
dimensions in figure 26 and table 12 to remove the
bellows nut (key 51) as follows:
a. Insert the bellows nut tool into the extension
bonnet (key 39). Be certain the tool lugs are
engaged in the corresponding recesses in the
bellows nut.
b. Use a torque gun or driver having sufficient
torque capabilities according to table 11. Connect
the gun to a socket that snugly fits the hex head
on the bellows nut tool.
c. Insert the socket onto the hex head of the
bellows nut tool.
WARNING
Be careful to hold the torque gun,
attached socket, and tool at right
angles to the bellows nut when
applying torque. Tilting the gun and
socket while applying torque may
cause the lugs on the bellows nut tool
to suddenly disengage from the lugs
on the bellows nut thus causing
possible damage to the bellows nut
and possible personal injury.
d. Remove the bellows nut (key 51).
3. For both extension and bellows bonnet
constructions: Body nuts (key 7) attach the
extension bonnet (key 39) to the valve body (key 1).
Loosen these nuts approximately 3mm (1/8 inch).
Then loosen the extension bonnet-to-body gasketed
joint by either rocking the extension bonnet or prying
between the body and extension bonnet. Work the

GX Valve and Actuator
Instruction Manual
February 2009
16
prying tool around the extension bonnet until it
loosens.
4. Remove the body nuts (key 7) completely and
carefully lift the extension bonnet (key 39), and valve
plug/stem extension assembly (key 3, 40 and 48) or
plug/bellows/stem extension assembly (key 3, 49
and 48) from the top of the valve body.
5. Use a wrench to unscrew the plug/stem assembly
(key 3) from the stem extension (key 40) or from
bellows/stem assembly (key 49) as follows:
a. Insert the wrench onto the stem extension hex
flats (see figures 22 and 23).
CAUTION
In the following procedure, take
precautions to ensure the valve plug
and stem finish are not damaged.
b. Clamp the plug/stem assembly (key 3) and
holding it stable, unscrew the stem extension
(key 40) or bellows/stem assembly (key 49). Take
precautions to ensure the valve plug and stem
finish are not damaged.
Note: There is a stem assembly locking insert
(figures 22 and 23, key 48) in the valve plug/stem
extension assembly. It is possible this insert
may drop out during stem disassembly. If this is
the case, ensure it is retained for reassembly of
the valve stem to the stem extension.
6. Remove the plug/stem assembly (key 3) and
bellows/stem assembly (key 49) from the extension
bonnet. Remove the bellows gasket (key 50).
7. Proceed to the Seat Ring Removal section.
Seat Ring / Cage Removal
CAUTION
Use care to avoid damaging the gasket
sealing surfaces.
The surface finish of the valve stem
(key 3) is critical for making a good
packing seal. The seating surfaces of
the seat ring (key 2), cage (key 99), and
the valve plug (key 3) are critical for
tight shutoff and should therefore also
be treated with care and properly
protected.
1. Packing parts can be removed from the bonnet if
desired. Replace these parts as described in the
section on Packing Maintenance.
2. Use a seat ring tool made according to the
dimensions in figure 5 and table 7 to remove the
seat ring (key 2) as follows:
a. Insert the tool into the valve body. Be certain
the tool lugs are engaged in the corresponding
recesses in the seat ring.
b. Use a torque gun or driver having sufficient
torque capabilities according to table 9. Connect
the gun to a socket that snugly fits the hex head
on the seat ring tool.
c. Insert the socket onto the hex head of the seat
ring tool.
WARNING
Be careful to hold the torque gun,
attached socket, and tool at right
angles to the seat ring when applying
torque. Tilting the gun and socket
while applying torque may cause the
lugs on the seat ring tool to suddenly
disengage from the lugs on the seat
ring thus causing possible damage to
the seat ring and possible personal
injury.
3. Remove the seat ring (key 2) from the valve
body.
4. Inspect parts for wear or damage that would
prevent proper operation of the valve body.
5. Replace trim parts as necessary.
Valve Trim Assembly
Assembly of Unbalanced Trim
Refer to figures 12, 18, 19, 20, 21, 22, 23, and 25.
1. Before installing the new seat ring / cage,
thoroughly clean the threads in the valve body port.
Apply suitable lubricant to the threads and to the 60q
surface of the new seat ring (key 4). Screw the seat

GX Valve and Actuator
Instruction Manual
February 2009
17
ring into the valve body. Using the seat ring tool,
tighten the seat ring and torque according to the
values in table 9. Remove all excess lubricant after
tightening.
2. For standard bonnet constructions, perform
the following. (Proceed to step 3 for extension
and bellows bonnets.)
a. Clean the body/yoke gasket seating surfaces
and install a new body/yoke gasket (key 5).
b. Remove any protective tape or covering from
the valve plug/stem assembly.
c. Insert the valve plug/stem assembly into the
seat ring.
CAUTION
If the packing is to be reused and was
not removed from the bonnet, perform
the following step carefully to avoid
damaging the packing with the stem
threads.
d. Install bonnet and actuator yoke onto the
valve body by completing the assembly according
to steps 15 to 27 of the section Replacing
Packing, omitting step 16 if new packing is not
being installed.
3. For extension and bellows bonnet
constructions, perform the following.
a. For bellows bonnet constructions, clean
the extension bonnet/bellows gasket seating
surfaces and install a new bellows gasket
(key 50).
b. Remove any protective tape or covering from
the valve plug/stem assembly (key 3). Then insert
the plug/stem assembly (key 3) through the
extension bonnet bushing (key 41).
c. Remove any protective tape or covering from
the stem extension (key 40) or the bellows stem
assembly (key 49). Screw the plug/stem
assembly (key 3) into the stem extension or
bellows/stem assembly. Note: Do not apply
lubricant to the threads of the plug/stem
assembly (key 3) or the bellows/stem
assembly (key 49).
Note: Ensure the stem assembly locking insert
(figures 22 and 23, key 48) has been first inserted
in the bottom of the threaded hole in the stem
extension.
CAUTION
In the following procedure, take
precautions to ensure the valve plug
and stem finish are not damaged.
d. Clamp the plug/stem assembly (key 3) and
hold it stable. Using a box spanner tool tighten
the plug/stem assembly (key 3) into the stem
extension (key 40) or into the bellows/stem
assembly (key 49) according to the stem
extension torque requirements listed in table 10.
Take precautions to ensure the valve plug and
stem finish are not damaged.
e. For bellows bonnet constructions, apply
suitable lubricant to the threads and to the bottom
surface of the bellows nut (key 51). Screw the
bellows nut into the extension bonnet. Using the
bellows nut tool, a lathe or boring mill, tighten the
bellows nut or torque according to the values in
table 11. Remove all excess lubricant.
f. Clean the body/extension bonnet seating
gasket surface and install the gasket (key 5).
g. Install the extension bonnet and plug/stem
assembly onto the valve body. Install the
body/yoke nuts (key 7) and tighten evenly using a
cross-tightening procedure. See table 4 for torque
requirements.
CAUTION
If the packing is to be reused and was
not removed from the bonnet, perform
the following step carefully to avoid
damaging the packing with the stem
threads.
h. Install the bonnet and actuator yoke onto the
extension bonnet by completing the assembly
according to steps 15 to 27 of the section
Replacing Packing, omitting step 16 if new
packing is not being installed.
Assembly of Balanced Trim
(Available in DN 80, 100, and 150 [NPS 3, 4, and 6]
only)

GX Valve and Actuator
Instruction Manual
February 2009
18
Refer to figure 10.
CAUTION
To protect the valve plug seal ring (key
37) and to ensure it seals properly, be
careful not to scratch the surfaces of the
ring groove in the valve plug or any of
the surfaces of the replacement ring.
1. With the valve plug (key 3) removed according to
the Disassembly portion of the Valve Trim
Maintenance procedure, proceed as appropriate:
The seal ring (key 37) cannot be reused because it
is a closed ring which must be pried and/or cut from
the groove. Once the seal ring is removed, the
elastomeric backup ring (key 38), which is also a
closed ring, can be pried from the groove.
To install a new backup ring and seal ring onto the
valve plug, apply a general purpose silicone-base
lubricant to both rings (keys 38 and 37). Place the
backup ring over the valve plug (key 3) and into the
groove. Place the seal ring over the top edge of the
valve plug (key 3) so that it enters the groove on one
side of the valve plug. Slowly and gently stretch the
seal ring and work it over the top edge of the valve
plug. The PTFE material in the seal ring must be
permitted time to cold-flow during the stretching
procedure, so avoid jerking sharply on this ring.
Stretching the seal ring over the valve plug may
make it seem unduly loose when in the groove, but it
will contract to its original size after insertion into the
bonnet.
2. Install the seat ring, valve plug/stem, bonnet and
actuator yoke into the valve body by completing the
assembly according to steps 1 to 3 of the section
Assembly of Unbalanced Trim.
Repair Nameplate
If required by the end-user, an optional repair
nameplate is available for recording changes made
to the valve trim during maintenance (see figure 28).
This nameplate can be ordered as a spare part, and
is easily mounted to the actuator casing using a
casing bolt. (Reference the Parts Ordering section of
this manual.)
As shown in figure 28, the repair nameplate provides
locations for maintenance personnel to record trim
data, such as:
DDate of maintenance
DTrim material
DPort diameter
DFlow capacity (Cv/ Kv)
DFlow characteristic
DActuator Action ATO/ATC
Bellows Maintenance
This section provides instruction on the replacement
of the bellows / stem assembly (see key 49 in
figure 23).
1. Remove the actuator, bonnet assembly as
described in the Replacing Packing section (steps 1
through 10).
2. Remove the plug/stem assemblies as described
in the Valve Trim Disassembly section (steps 2
through 6).
3. To install the new bellows / stem assembly
(key 49), perform the Valve Trim Assembly (step 3).

GX Valve and Actuator
Instruction Manual
February 2009
19
GE11642-1 AIR-TO-CLOSE, SPRING-TO-OPEN AIR-TO-OPEN, SPRING-TO-CLOSE
STUD AND
NUT (4) STUD AND
NUT (4)
LOCKING
SCREW
LOCKING
SCREW
Figure 6. Fisher GX Handwheel Assembly
AIR-TO-CLOSE, SPRING-TO-OPENAIR-TO-OPEN, SPRING-TO-CLOSE
GE05809-D GE05810-D
APPLY LUBRICANT
Figure 7. Fisher GX Handwheel Orientation and Grease Zerk Location

GX Valve and Actuator
Instruction Manual
February 2009
20
Handwheel Operation
CAUTION
This handwheel is designed only for
use with size 225 and 750 actuators
with 20 mm travel. To avoid equipment
damage, do not assemble this travel
stop on size 750 actuators with 40 mm
travel or size 1200 actuators.
Principle of Operation
The GX handwheel is designed to compress the
actuator springs and override the actuator fail action.
Turning the handwheel drives the screw, nut, and
levers. The levers push against the stem connector
to transfer this motion. Reversing the direction of the
handwheel will move the nut and levers in the
opposite direction. Once the levers are no longer in
contact with the stem connector, the locking screw
should be used to secure the handwheel against
undesired movement. To prevent damage due to
overtravel, the handwheel should not be turned more
than 2 full turns past the point at which the levers no
longer contact the stem connector.
WARNING
To avoid personal injury or loss of
process control due to equipment
damage, ensure the levers are
completely disengaged and the
locking screw is tight while the valve is
in normal pneumatic operation.
During normal pneumatic operation when the
handwheel is not needed, a locking screw (see
figure 6) is provided on the side of the handwheel
housing to lock the handwheel levers out of the way.
WARNING
To avoid personal injury or equipment
damage due to possible sudden
shifting or falling of the valve
assembly, do not lift the valve
assembly by the handwheel.
GX Handwheel Installation
(for use with 20mm travel only)
1. Note the orientation of the levers to the stem
connector for either the air-to-close, spring-to-open
configuration or for the air-to-open, spring-to-close
configuration, as shown in figure 7.
2. Adjust the handwheel to allow positioning the
levers above the stem connector before installation.
3. Install the handwheel to the GX mounting pad
with four studs and nuts, as shown in figure 6.
Torque to 24 NSm (18 lbfSft).
4. Apply lithium grease to the grease zerk and to the
tip of the levers (where they contact the stem
connector), as shown in figure 7.
Travel Stop Operation
Principle of Operation
CAUTION
This travel stop is designed only for
use with size 225 and 750 actuators
with 20 mm travel. To avoid equipment
damage, do not assemble this travel
stop on size 750 actuators with 40 mm
travel or size 1200 actuators.
The GX travel stop is designed to mechanically limit
and stop the valve at a preset position in an
emergency or upon loss of instrument air. This
assembly is mounted on the yoke with four studs.
The lever pushes against the stem connector to stop
the travel. Travel position can be adjusted by two
adjustable cap screws on the lever, as shown in
figure 8. A cover plate assembly is available to
prevent pinch point damage caused by the lever, as
shown in figure 8.
WARNING
To avoid personal injury or equipment
damage due to possible sudden
shifting or falling of the valve
assembly, do not lift the valve
assembly by the travel stop.
To avoid personal injury or loss of
process control due to equipment
damage, screw the adjustable cap
screws to ensure the lever is
completely disengaged while the valve
is in normal pneumatic operation.