Emerson Fisher 657C User manual

www.Fisher.com
Fisher™657C Diaphragm Actuator
Sizes 40i, 46i, and 60i
Contents
Introduction 1.................................
Scope of Manual 1.............................
Description 2.................................
Specifications 2...............................
Educational Services 3.........................
Installation 3..................................
Mounting the Actuator on the Desuperheater 4....
Discussion of Bench Set 7.......................
Spring Verification 7...........................
Installing the Stem Connector Assembly 9.........
Friction Discussion 10..........................
Deadband Measurement 11.....................
Loading Connection 11.........................
Maintenance 12................................
Actuator Maintenance 12.......................
Top‐Mounted Handwheel Assembly 14...........
Casing‐Mounted Adjustable Travel Stops 16.......
Parts Ordering 18...............................
Parts Kits 18...................................
Kits for Top‐Mounted Handwheels 18.............
Kits for Adjustable Down Travel Stops 18..........
Parts List 19...................................
Actuator Assembly (figures 7, 8, and 9) 19.........
Figure 1. Fisher 657C Actuator
Introduction
Scope of Manual
This instruction manual provides information on installation, adjustment, maintenance, and parts ordering for the
Fisher 657C actuator in sizes 40i, 46i, and 60i. Refer to separate instruction manuals for information about the
desuperheater positioner and other accessories used with these actuators.
Do not install, operate, or maintain a 657C actuator without being fully trained and qualified in Yarway™
desuperheater, actuator, and accessory installation, operation, and maintenance. To avoid personal injury or property
damage, it is important to carefully read, understand, and follow all the contents of this manual, including all safety
cautions and warnings. If you have any questions about these instructions, contact your Emerson sales office before
proceeding.
Instruction Manual
D104496X012
657C Actuator (40i, 46i, and 60i)
November 2019

Instruction Manual
D104496X012
657C Actuator (40i, 46i, and 60i)
November 2019
2
Table 1. Specifications
SPECIFICATION ACTUATOR SIZE
40i 46i 60i
Nominal Effective Area cm
2
445 1006 1006
Inch
2
69 156 156
Acceptable Desuperheater
Stem Diameters 12 mm or 1/2 inch 12 mm or 1/2 inch 16 mm
Yoke Boss Diameters mm 71 71 91
Inches 2‐13/16 2‐13/16 3‐9/16
Maximum Allowable
Output Thrust(1)
N 12010 30246 30246
Lb 2700 6800 6800
Maximum Travel(3) mm 89 105 105
Inches 3-1/2 4-1/8 4-1/8
Maximum Casing
Pressure for
Actuator Sizing(1)
Bar 4.5 2.8 2.8
Psig 65 40 40
Maximum Diaphragm
Casing Pressure(1)(2)
Bar 5.2 3.4 3.4
Psig 75 50 50
Operating Temperature Range Nitrile Elastomers: -40 to 82_C (-40 to 180_F),
Silicone Elastomers: -54 to 149_C (-65 to 300_F)
Pressure Connections
(internal)
1/4 NPT X X X
1/2 NPT
(optional) X X X
Approximate Weights kg 34 66 72
Lb 75 146 160
1. Normal operating diaphragm pressure must not exceed maximum diaphragm casing pressure and must not produce a force on the actuator stem greater than the maximum allowable
output thrust or the maximum allowable stem load. Contact your Emerson sales office for more information concerning maximum allowable stem load.
2. This maximum casing pressure is not to be used for normal operating pressure. Its purpose is to allow for typical regulator supply settings and/or relief valve tolerances.
3. Actuator travel may be less than the value listed after connecting the actuator to the valve.
Description
The Fisher 657C actuators (figure 1) are long stroke, spring opposed, direct‐acting diaphragm actuators. They are
designed for Yarway desuperheater line of products (AT-38/48, AT-37/47, AT-18/28, and 4300 Templow™). They are
suitable for push‐down‐to‐open (PDTO) applications and are available in sizes 40i, 46i and 60i to provide 89 mm (3.5
inch), or 105 mm (4.125 inch) maximum actuator travel.
A 657C actuator can be equipped with a top-mounted handwheel assembly. Adjustable casing-mounted down travel
stop is also available for this actuator.
Specifications
Refer to table 1 for Specifications of the 657C actuator. See the actuator nameplate for specific information about your
actuator.

Instruction Manual
D104496X012
657C Actuator (40i, 46i, and 60i)
November 2019
3
Figure 2. Schematic of Fisher 657C Actuator
SPRING LIFTS
STEM UP
AIR PUSHES
STEM DOWN
STEM
AF3833‐A
A0792‐2
Educational Services
For information on available courses for Fisher 657C diaphragm actuators, as well as a variety of other products,
contact:
Emerson Automation Solutions
Educational Services - Registration
Phone: [phone] or 1-800-338-8158
E-mail: [email protected]
emerson.com/fishervalvetraining
Installation
Key number locations are shown in figure 7 unless otherwise indicated. Also, refer to figure 3 for location of parts.
WARNING
Always wear protective gloves, clothing, and eyewear when performing any installation operations to avoid personal
injury.
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
To avoid parts damage, do not use an operating pressure that exceeds the Maximum Diaphragm Casing Pressure (table 1)
or produces a force on the actuator stem greater than the Maximum Allowable Output Thrust (table 1) or the maximum
allowable desuperheater stem load. (Contact your Emerson sales office with questions concerning maximum allowable
desuperheater stem load.)

Instruction Manual
D104496X012
657C Actuator (40i, 46i, and 60i)
November 2019
4
D Desuperheater/Actuator Assembly: If the actuator and desuperheater are shipped together as an assembly, it has
been adjusted at the factory, and may be installed in the pipeline. After installing the desuperheater in the pipeline,
refer to the Loading Connection procedures.
D Actuator Mounting: If the actuator is shipped separately or the actuator has been removed from the desuperheater,
the actuator should be mounted to the desuperheater before placing the desuperheater in the pipeline when
practical. Refer to the actuator mounting procedures before placing the desuperheater in service. You may perform
the Bench Set Spring Adjustment procedures in this section to confirm the adjustment has not changed since it was
shipped from the factory. Support actuator when in any other position than vertical.
D Positioner: If a positioner is installed, or is to be installed on the actuator, refer to the positioner instruction manual
for installation. During the adjustment procedures, it will be necessary to provide a temporary loading pressure to
the actuator diaphragm.
Mounting the Actuator on the Desuperheater
The 657C actuator spring loading pushes the actuator stem up towards the actuator diaphragm (see figure 2). This
spring action moves the stem away from the desuperheater while installing the actuator.
CAUTION
If the valve stem is allowed to remain in the up position (towards the actuator) during mounting, it can interfere with the
actuator mounting, possibly damage valve stem threads or bend the valve stem. Be sure the valve stem is pushed down
(into the valve body), away from the actuator while mounting.
Provide a temporary method of applying diaphragm loading pressure to the diaphragm to extend the actuator stem
during bench set spring adjustments. Provide a regulator to adjust the actuator stem during bench set spring
adjustments and a shut-off valve to isolate and prevent unwanted movement.
1. Provide a vise or some other method of supporting the desuperheater and the weight of the actuator during
assembly. Push the desuperheater stem down away from the actuator while mounting the actuator.
2. Screw the stem locknuts all the way onto the desuperheater stem. With the concave side of the travel indicator disk
(key 14, figure 7) facing the desuperheater, install the travel indicator disk on the desuperheater stem.
3. Lift or hoist the actuator onto the desuperheater yoke mounting boss:
a. Screw the yoke locknut onto the desuperheater yoke mounting boss and tighten the locknut. (Note: On small
size actuators, it may be necessary to remove the indicator disk and re‐install it while lowering the actuator on to
the desuperheater because the disk will not go through the actuator yoke opening.)
4. Do not connect the actuator stem to the desuperheater stem at this time. Whenever the actuator is installed on the
desuperheater , it is recommended to perform the Bench Set Spring Adjustment procedure to verify that the
actuator is still adjusted correctly.

Instruction Manual
D104496X012
657C Actuator (40i, 46i, and 60i)
November 2019
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Figure 3. Actuator Components for Size 40i, 46i, and 60i Actuators
DIAPHRAGM CASINGS
DIAPHRAGM
DIAPHRAGM PLATE
ACTUATOR SPRING
SPRING SEAT
SPRING ADJUSTOR
STEM CONNECTOR
TRAVEL INDICATOR
INTEGRAL INSTRUMENT PAD
YOKE
TRAVEL STOP
INDICATOR SCALE
ACTUATOR STEM
YOKE EXTENSION

Instruction Manual
D104496X012
657C Actuator (40i, 46i, and 60i)
November 2019
6
Figure 4. Construction of Yarway Desuperheater
MATCH LINE FOR
ACTUATOR
DESUPERHEATER STEM
YOKE LOCK NUT
YOKE BOSS DIAMETER
YARWAY DESUPERHEATER

Instruction Manual
D104496X012
657C Actuator (40i, 46i, and 60i)
November 2019
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Discussion of Bench Set
The bench set pressure values are used to adjust the initial compression of the actuator spring with the
desuperheater‐actuator assembly “on the bench.” The correct initial compression is important for the proper
functioning of the desuperheater‐actuator assembly when it is put into service and the proper actuator diaphragm
operating pressure is applied.
The bench set values are established with the assumption that there is no packing friction. When attempting to adjust
the spring in the field, it is very difficult to ensure that there is no friction being applied by “loose” packing.
Accurate adjustment to the bench set range can be made during the actuator mounting process by making the
adjustment before the actuator is connected to the desuperheater (see the Spring Verification procedure).
Figure 5. Bench Set Adjustment
SPRING ADJUSTER
LOWER BENCH SET
LOADING PRESSURE
UPPER BENCH SET
PRESSURE MARK
VALVE STEM
RATED VALVE
TRAVEL MEASURE
MARK VALVE
STEM HERE
UPPER BENCH
SET LOADING
PRESSURE
ACTUATOR STEM
NOTES:
THE LOWER PSIG LOADING PRESSURE (MARKED ON NAMEPLATE) WHERE THE FIRST MOVEMENT OF
ACTUATOR STEM IS DETECTED.
THE UPPER PSIG LOADING PRESSURE EXTENDS ACTUATOR STEM.
MARK THIS POINT WITH TAPE OR A MARKER.
MEASURE DISTANCE OF TRAVEL. IT SHOULD EQUAL THE TRAVEL SPAN SHOWN ON THE NAMEPLATE.
2
3
1
3
4
1
2
3
4
Spring Verification
Ensure that the actuator stem is at the top of its travel as shown in figure 5 and not connected to the desuperheater.
Note
Some spring compression is required to move the diaphragm to the top of its travel.
The steps provided are for push-down-to-open desuperheaters.

Instruction Manual
D104496X012
657C Actuator (40i, 46i, and 60i)
November 2019
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WARNING
When moving the actuator stem with diaphragm loading pressure, use caution to keep hands and tools out of the actuator
stem travel path. Personal injury and/or property damage is possible if something is caught between the actuator stem and
other desuperheater assembly parts.
Also, provide a certified pressure gauge suitable to accurately read the diaphragm pressure from 0 through 0.3 bar (5
psig) above the upper operating range pressure marked on the nameplate. Apply loading pressure to the diaphragm.
CAUTION
Stroke the actuator a few times to ensure that the pressure gauge is working correctly, and that the actuator is functioning
properly. To prevent actuator damage, it is important to ensure that the actuator stem is stroking smoothly and not
exhibiting binding or excessive friction. Binding or excessive friction could be an indicator of incorrect assembly or
damaged parts.
1. If not already accomplished, provide a regulator to apply an adjustable loading pressure to the actuator during
bench set adjustments and a shut-off valve to isolate and prevent the unwanted movement.
2. Set the diaphragm loading pressure at 0 bar (0 psig). Then, slowly raise the pressure towards the lower bench set
pressure, as indicated on the nameplate, while checking for the first linear movement of the actuator stem. The
actuator stem should show movement at the lower bench set pressure. If movement occurs before or after the
lower pressure is reached, adjust the spring adjuster (see figure 5) into or out of the yoke until the actuator stem's
movement is first detected at the lower bench set pressure.
3. Be sure the spring adjuster is adjusted to meet the requirements of step 2 above.
4. Apply the upper bench set pressure, as indicated on the nameplate. This pressure extends the actuator stem down
toward the desuperheater. At the end of the actuator stem, use a marker or a piece of tape to mark the
desuperheater stem (see figure 5).
Note
The actuator stem may slide over the desuperheater stem as shown in figure 5. If the actuator stem does not pass over the
desuperheater stem, provide a method to mark this point of stem travel.
5. Slowly decrease the diaphragm loading pressure to the lower bench set pressure, as indicated on the nameplate.
6. Measure the distance between the marker or tape on the desuperheater stem to the end of the actuator stem. The
distance should match the rated travel indicated on the nameplate.
7. If the measured travel matches the nameplate travel, bench set is complete. Proceed to the Installing the Stem
Connector Assembly subsection.
8. If the measured travel is not exact, consider the spring free-length and spring rate tolerances may produce a slightly
different bench set than specified. Contact your Emerson sales office for assistance.

Instruction Manual
D104496X012
657C Actuator (40i, 46i, and 60i)
November 2019
9
Installing the Stem Connector Assembly
When installing the stem connector assembly (key 26), the actuator and desuperheater stem threads should engage
the threads of the stem connector by the distance equal to the diameter of the stem.
WARNING
Install the stem connector securely before a positioner is mounted to the actuator and pressurized, using only a
regulator-controlled air supply, not the positioner, to move the actuator stem.
To avoid personal injury or property damage, keep hands and tools out of the actuator stem travel path while applying
loading pressure to move the actuator stem in the following steps.
CAUTION
To avoid damaging the seating surfaces, do not rotate the desuperheater plug while it is seated. Exercise care while
installing the stem connector assembly to avoid damage to the desuperheater plug stem and desuperheater stem threads.
Note
Replacement stem connectors are an assembly of two stem connector halves, cap screws, and a spacer between the connector
halves. Remove the spacer and discard, if present, before clamping the actuator and desuperheater stems together. Use only a
mated pair of stem connector halves.
1. Pull the desuperheater stem up so that it is touching the seat ring.
If necessary, screw the desuperheater stem locknuts down, away from the connector location. For all actuators,
ensure that the travel indicator disk (key 14) is located on top of the locknuts.
2. Actuator should be at lower bench set.
3. Place the stem connector half with the threaded holes, approximately half way between the actuator and
desuperheater stems, and align with the stem connector. A slight change to loading pressure may be necessary to
align the threads. Refer to figure 7 to help locate the connector position.
CAUTION
Incomplete engagement of either the desuperheater stem or actuator stem in the stem connector can result in stripped
threads or improper operation. Be sure that the length of each stem clamped in the stem connector is equal to or greater
than one diameter of that stem. Damage to threads on either stem or in the stem connector can cause the parts to be
replaced prematurely. Do not loosen the cap screws when the stem connector has spring or loading pressure force applied.
4. Install the other half of the stem connector and insert the lubricated cap screws and tighten them while ensuring
even spacing between the stem connector halves on all sides. If installing a positioner, also attach the feedback
bracket at the same time.
CAUTION
Over‐tightening the desuperheater stem locknuts can make disassembly difficult.

Instruction Manual
D104496X012
657C Actuator (40i, 46i, and 60i)
November 2019
10
5. Screw the desuperheater stem locknuts up until the indicator disk contacts the bottom of the stem connector. Do
not overtighten the locknuts.
6. Slowly stroke the desuperheater from fully closed to fully open and verify full rated travel is achieved.
Be sure the desuperheater is in the closed position. Loosen the screws (key 17) on the travel indicator scale (key 18),
and align it with the travel indicator disk (key 14). Stroke the desuperheater full travel to ensure that the travel
matches the rated travel on the nameplate. If desuperheater travel is not correct, repeat the stem connector
procedure.
Friction Discussion
If you are attempting to adjust the bench set after the actuator is connected to the desuperheater and the packing
tightened, you must take friction into account. Make the spring adjustment so full actuator travel occurs at the bench
set values
a. Add the friction force divided by the effective diaphragm area with increasing diaphragm pressure, or,
b. Subtract the friction force divided by the effective diaphragm area with decreasing diaphragm pressure.
If the stem connector assembly has been installed, the desuperheater friction may be determined by the following
procedure:
1. Install a pressure gauge in the actuator loading pressure line that connects to the actuator diaphragm casing.
Note
Steps 2 and 4 require that you read and record the pressure shown on the pressure gauge.
2. Increase the actuator diaphragm pressure and read the diaphragm pressure as the actuator reaches a travel
position in the rated travel of the desuperheater that does not contact a travel stop. Make a reference mark on the
travel indicator scale using tape or some other method at this point.
3. Increase the actuator diaphragm pressure until the actuator is at a travel position greater than the position
referenced in step 2 using the reference point to identify first movement.
4. Decrease the actuator diaphragm pressure and read the diaphragm pressure as the actuator returns to the position
referenced in step 2.
The difference between the two diaphragm pressure readings is the change in the diaphragm pressure required to
overcome the friction forces in the two directions of travel.
5. Calculate the actual friction force:
Friction
Force, = 0.5
pounds
Difference
in pressure
readings, psig

Effective
diaphragm area,
inches2
Refer to table 1 for the effective diaphragm area.
It is difficult to rotate the spring adjustor (key 12, figure 7) when the full actuator loading pressure is applied to the
actuator. Release the actuator loading pressure before adjusting. Then re-apply loading pressure to check the
adjustment.
Note
The actuator down stop is the limit for downward movement, and the desuperheater seat is the limit for upward (away from the
desuperheater) movement.