Emerson Fisher 785C User manual

www.Fisher.com
Fisher™785C Piston Actuators
Contents
Introduction 1.................................
Scope of Manual 1.............................
Description 3.................................
Specifications 3...............................
Educational Services 3.........................
Principle of Operation 3.........................
Installation 7..................................
Actuator Earth Grounding 9.....................
Three‐Way Valve Applications Note 9.............
Manual Override 9.............................
Handwheel Operation 10.......................
Manual Hydraulic Handpump Operation 12........
Actuator Mounting 22...........................
Maintenance 23................................
Actuator Removal 23..........................
Disassembling the Pneumatic Cylinder 24.........
Replacing the Pneumatic Cylinder Seals 25........
Assembling the Pneumatic Cylinder 27...........
Lubrication 28................................
Disassembling the Handpump Hydraulic Cylinder 30
Handpump Hydraulic Cylinder Seals Replacement 30
Handpump Hydraulic Cylinder Reassembly 30.....
Other Maintenance Specifications 32.............
Troubleshooting 35.............................
Parts Ordering 36...............................
Parts Kits 36...................................
Parts List 47...................................
Assembly Drawings 50..........................
Figure 1. Fisher 785C Single-Acting Spring Return
with Handpump
X1851
Introduction
Scope of Manual
This instruction manual includes installation, maintenance, and parts information for the Fisher 785C piston actuator.
Refer to separate instruction manuals for information regarding other equipment and accessories used with these
actuators.
Do not install, operate, or maintain 785C actuators without being fully trained and qualified in valve,
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
D104483X012
785C Actuator
May 2022

Instruction Manual
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785C Actuator
May 2022
2
Table 1. Specifications
Operating Pressure(1)
Minimum: 2.7 barg (40 psig)
Maximum Allowable: 10.3 barg (150 psig)
Consult your Emerson sales office for supply
pressures under 2.7 barg (40 psig)
Travel(2)
16 mm (0.625 inch) through 610 mm (24 inch)
See table 2 and 4
Thrust Capabilities
See table 3, 6, and 7
Stroking Speeds
Varies with actuator size, spring, travel, and supply
pressure. If stroking speed is critical, consult your
Emerson sales office.
Piston Diameter and Area(2)
Available diameters range from 280 to 685 mm
(11 to 27 inches).
See table 2, 4, and 5
For additional sizes, contact your Emerson sales
office.
Operative Temperature Limits(3)
Standard: -20 to 100_C (-4 to 212_F)
Low Temperature Options:
-40 to 100_C (-40 to 212_F) or
-60 to 100_C (-76 to 212_F)
High Temperature Option:
-20 to 200_C (-4 to 392_F)
Yoke Boss and Valve Stem Diameter
Standard: J90 mm (3-9/16 inch) yoke boss with
19 mm (3/4 inch) stem J127 mm (5 inch) yoke boss
with 25.4 mm (1 inch) stem J127 mm (5H) yoke
boss with 32 mm (1-1/4 inch) stem J178 mm
(7 inch) yoke boss with 51 mm (2 inch) stem
High Performance: J127 mm (5H) yoke boss with
32 mm (1-1/4 inch) stem J178 mm (7 inch) yoke
boss with 51 mm (2 inch) stem
Pressure Connections
Standard: 3/4 NPT
Optional: 1 and 1-1/4 NPT
Instrument Mounting
Standard mounting kits are available for use with
FIELDVUE DVC6200 Series digital valve controllers up
to 610 mm (24 inch) travel. High performance
mounting kits are available for travel above 203 mm
(8 inch).
Construction Materials(4)
Part Material
Cylinder Carbon Steel
Nameplate and Travel Scale Stainless Steel
Piston Carbon Steel
Piston Rod Stainless Steel
Stem Connector Carbon Steel or Stainless Steel
Tie Rod Carbon Steel or Stainless Steel
Upper/Lower Heads Carbon Steel
Yoke Carbon Steel
Lifting Point Load Ratings
See table 8 and figure 2
Options
JTop mounted handwheel
JSide mounted handpump
JPneumatic fail mode via Fisher 377 trip valve
JVolume boosters
Optional Certifications(5)
JPressure Equipment Directive (PED) 2014/68/EU
and Machinery Directive 2006/42/EC
JATEX Group II Category 2 Gas and Dust
JCustoms Union Technical Regulations (CUTR)
010/2011 and 012/2011
JSafety Instrumented System, SIL 3 Capable
JInspection Documents EN 10204 3.1 Certificate
1. The pressure/temperature limits in this bulletin and any other applicable standard or code should not be exceeded.
2. Consult your Emerson sales office for longer travels or larger cylinder diameters. The Fisher 585C family of actuators can be used for smaller travels or cylinder diameters.
3 Standard temperature -20 to 100_C (-4 to 212_F) and -40 to 100_C (-40 to 212_F) are PED 2014/68/EU and 2006/42/EC compliant. The low ambient temperature option, -60 to 100_C (-76 to 212_F)
is not PED compliant. The high temperature option, if used in conjunction with ATEX, is limited to 135_C (275_F).
4. Full stainless steel constructions are available upon request.
5. Refer to the product nameplates to determine which certifications each actuator construction possesses

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Description
The 785C product lines encompass medium to large spring-return single-acting and double-acting piston actuators
that provide accurate, high thrust output for short to long travel applications. These actuators are designed for use
with a variety of medium to large Fisher sliding-stem control valves.
The single-acting actuators feature an internal bias spring that forces the actuator piston rod to extend or retract upon
a loss of supply pressure, thereby ensuring a fail-closed or fail-open mode of operation. This effectively eliminates the
need for a trip valve and volume tank in most constructions.
Specifications
Specifications for the 785C line of piston actuators are shown in tables 1 to 8. Refer to the nameplate affixed to the
actuator yoke for specifications specific to individual constructions.
Educational Services
Emerson Automation Solutions
Educational Services - Registration
Phone: [phone]
E-mail: [email protected]
emerson.com/mytraining
Principle of Operation
785C piston actuators utilize a pneumatically controlled piston that moves inside of a cylinder to generate thrust. A
seal contained on the circumference of the piston provides a seal between the top and bottom of the cylinder,
preventing supply pressure leakage.
785C single-acting or double-acting spring-return piston actuators utilize a spring below the piston (outside the
pressurized chamber) that will drive the piston rod upon a loss of supply pressure. This fail action will result in forcing
an attached control valve to either fail-open or fail-closed. The fail action of 785C double-acting springless piston
actuators relies on pneumatic system such as system with Fisher 377 trip valve.
From an equilibrium state, the actuator operates by reacting to a force unbalance that is created by change of supply
pressure on one side of the piston for single-acting, or a change of differential pressure between each side of the
piston for double-acting. This moves the piston up or down, and results in a repositioning of the attached control
valve. Travel can be adjusted using travel limits within a valve positioner, which limit the travel range of the actuator.
The option of a hard travel stopper is also available, consult your Emerson sales office for details. The optional manual
override does not have the ability to act as a hard travel stop.
An optional manual override (top mounted handwheel or side mounted handpump) is capable of extending or
retracting the actuator manually and can be engaged at any position from full open to full close. The top-mounted
handwheel utilizes an engagement lever that couples the handwheel and piston rod. The handpump has a hydraulic
cylinder attached to the piston rod. This enables the handpump to operate the actuator manually, unless the
handpump is set to bypass position.

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Table 2. 785C Double-Acting Springless Standard Constructions(1)
ACTUATOR
SIZE
PISTON AREA VALVE STEM
CONNECTOR SIZE
YOKE BOSS
DIAMETER MAX TRAVEL
Without Manual
Override
With Manual
Override(2)
cm2Inch2cm2Inch2mm Inch mm Inch mm Inch
280 616 95 616 95
19 3/4 90 3 9/16 203 8
25 1 127 5
32 1 1/4 127 5H 610 24
335 881 137 881 137
19 3/4 90 3 9/16 203 8
25 1 127 5
32 1 1/4 127 5H 610 24
385 1164 180 1164 180
19 3/4 90 3 9/16 203 8
25 1 127 5
32 1 1/4 127 5H 610 24
51 2 178 7
435 1486 230 1474 228
25 1 127 5 203 8
32 1 1/4 127 5H 610 24
51 2 178 7
485 1847 286 1828 283
25 1 127 5 203 8
32 1 1/4 127 5H 610 24
51 2 178 7
535 2248 348 2228 345
25 1 127 5 203 8
32 1 1/4 127 5H 610 24
51 2 178 7
585 2688 417 2660 412 32 1 1/4 127 5H 610 24
51 2 178 7
635 3167 491 3139 487 32 1 1/4 127 5H 610 24
51 2 178 7
685 3685 571 3657 567 32 1 1/4 127 5H 610 24
51 2 178 7
1. Consult your Emerson sales office for additional sizes.
2. Actuator size 280-385 are available with a top mounted handwheel. Size 435-685 are available with a side mounted manual handpump.
3. High Performance Yoke required for ODV packages with travel greater than 8 inches. Optional for use in high vibration or fast stroke package. When ordering a high performance yoke boss
you will need to order a high performance mounting kit as well.
Table 3. 785C Double-Acting Springless Available Thrust
ACTUATOR SIZE
MAXIMUM ALLOWABLE
CYLINDER PRESSURE
MAXIMUM ALLOWABLE THRUST
Without Manual Override With Manual Override(1)
barg psig N lb N lb
280
10.3 150
63682 14316 32635 7337
335 91157 20493 46715 10502
385 120399 27067 61700 13871
435 153702 34554 78726 17698
485 191066 42953 132291 29740
535 232492 52266 132291 29740
585 277979 62492 172788 38844
635 327527 73631 172788 38844
685 381137 85683 238555 53629
1. Actuator size 280-385 are available with a top mounted handwheel. Size 435-685 are available with a manual handpump.

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Table 4. 785C Single-Acting Spring Return Standard Constructions(1)
ACTUATOR
SIZE
PISTON AREA VALVE STEM
CONNECTOR
SIZE
YOKE BOSS
DIAMETER MAX TRAVEL
Without Manual Override With Manual Override(2)
Rod Extends Rod Retracts Rod Extends Rod Retracts
cm2Inch2cm2Inch2cm2Inch2cm2Inch2mm Inch mm Inch mm Inch
335 881.4 136.6 868.9 134.7 881.4 136.6 868.9 134.7
19 3/4 90 3 9/16
203 8
25 1 127 5
32 1 1/4 127 5H
385 1164 180.4 1152 178.5 1164 180.4 1152 178.5
19 3/4 90 3 9/16 203 8
25 1 127 5
32 1 1/4 127 5H 318 12
51 2 178 7
435 1486 230.4 1474 228.4 1474 228.4 1474 228.4
25 1 127 5 203 8
32 1 1/4 127 5H 420 16
51 2 178 7
485 1847 286.4 1835 284.4 1828 283.3 1835 284.4
25 1 127 5 203 8
32 1 1/4 127 5H 420 16
51 2 178 7
535 2248 348.4 2235 346.5 2228 345.4 2235 346.5
25 1 127 5 203 8
32 1 1/4 127 5H 420 16
51 2 178 7
585 2688 416.6 2660 412.2 2660 412.2 2660 412.2 32 1 1/4 127 5H 420 16
51 2 178 7
635 3167 490.9 3139 486.5 3139 486.5 3139 486.5 32 1 1/4 127 5H 420 16
51 2 178 7
685 3685 571.2 3657 566.8 3657 566.8 3657 566.8 32 1 1/4 127 5H 420 16
51 2 178 7
1. Consult your Emerson sales office for additional sizes.
2. Actuator size 335-385 are available with a top mounted handwheel. Size 435-685 are available with a side mounted manual handpump.
Table 5. 785C Double-Acting Spring Return Standard Constructions(1)
ACTUATOR
SIZE
PISTON AREA VALVE STEM
CONNECTOR
SIZE
YOKE BOSS
DIAMETER MAX TRAVEL
Without Manual Override With Manual Override(2)
Rod Extends Rod Retracts Rod Extends Rod Retracts
cm2Inch2cm2Inch2cm2Inch2cm2Inch2mm Inch mm Inch mm Inch
280 615.8 95.4 603.2 93.5 615.8 95.4 603.2 93.5
19 3/4 90 3 9/16
203 8
25 1 127 5
32 1 1/4 127 5H
335 881.4 136.6 868.9 134.7 881.4 136.6 868.9 134.7
19 3/4 90 3 9/16
203 8
25 1 127 5
32 1 1/4 127 5H
385 1164 180.4 1152 178.5 1164 180.4 1152 178.5
19 3/4 90 3 9/16 203 8
25 1 127 5
32 1 1/4 127 5H 318 12
51 2 178 7
435 1486 230.4 1474 228.4 1474 228 1473 228.4
25 1 127 5 203 8
32 1 1/4 127 5H 420 16
51 2 178 7
485 1847 286.4 1835 284.4 1828 283 1835 284.4
25 1 127 5 203 8
32 1 1/4 127 5H 420 16
51 2 178 7
535 2248 348.4 2235 346.5 2228 345 2235 346.5
25 1 127 5 203 8
32 1 1/4 127 5H 420 16
51 2 178 7
585 2688 416.6 2660 412.2 2660 412 2660 412.2 32 1 1/4 127 5H 420 16
51 2 178 7
635 3167 490.9 3139 486.5 3139 486.5 3139 486.5 32 1 1/4 127 5H 420 16
51 2 178 7
- continued -

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Table 5. 785C Double-Acting Spring Return Standard Constructions(1) (continued)
ACTUATOR
SIZE
PISTON AREA VALVE STEM
CONNECTOR
SIZE
YOKE BOSS
DIAMETER MAX TRAVEL
Without Manual Override With Manual Override(2)
Rod Extends Rod Retracts Rod Extends Rod Retracts
cm2Inch2cm2Inch2cm2Inch2cm2Inch2mm Inch mm Inch mm Inch
685 3685 571.2 3657 566.8 3657 566.8 3657 566.8 32 1 1/4 127 5H 420 16
51 2 178 7
1. Consult your Emerson sales office for additional sizes.
2. Actuator size 280-385 are available with a top mounted handwheel. Size 435-685 are available with a manual handpump.
Table 6. Handwheel Specification
ACTUATOR
SIZE
OUTPUT THRUST HANDWHEEL DIAMETER TURNS PER mm
OF TRAVEL
TURNS PER INCH
OF TRAVEL
MAXIMUM RIM
FORCE REQUIRED
N lbs mm Inch N lbs
280 32635 7337 850 33 0.2 4.2 437 98
335 46715 10502 1200 47 0.2 4.2 435 98
385 61700 13871 1400 55 0.2 4.2 489 110
Table 7. Handpump Specification
ACTUATOR SIZE HYDRAULIC CYLINDER OUTPUT THRUST
mm Inch N lbf
435 135 5.3 78726 17698
485 175 6.9 132291 29740
535 175 6.9 132291 29740
585 200 7.9 172788 38844
635 200 7.9 172788 38844
685 235 9.3 238555 53629
Table 8. Lifting Point Load Ratings
ACTUATOR SIZE LIFTING ORIENTATION NUMBER OF LIFTING
POINTS USED
MAXIMUM WELDED EYELET LOAD
AT LIFTING ANGLE a3205
(SEE FIGURE 2)
Kg lbs
280
Actuator Centerline Horizontal(1)
2 1572 3466
335 2 1572 3466
385 2 1572 3466
435 2 1572 3466
485 2 5697 12560
535 2 5697 12560
585 2 5697 12560
635 2 5697 12560
685 2 5697 12560
ACTUATOR SIZE LIFTING ORIENTATION NUMBER OF LIFTING
POINTS USED
MAXIMUM LOAD AT EYEBOLT
LIFTING ANGLE a3455
(SEE FIGURE 2)
Kg lbs
280
Actuator Centerline Vertical(2)
4 864 1905
335 4 864 1905
385 4 864 1905
435 4 864 1905
485 4 3096 6826
535 4 3096 6826
585 4 3096 6826
635 4 3096 6826
685 4 3096 6826
1. Welded eyelets for horizontal lifting are only available for the 785C Spring Return.
2. Vertical lifting loads are applicable to both the 785C Springless and Spring Return.

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Figure 2. Lifting Angle N
N
SPRING RETURN ACTUATOR
CENTERLINE HORIZONTAL LIFT
785C ACTUATOR
VERTICAL HORIZONTAL LIFT
aa
aa
Installation
Key numbers in this procedure are shown in figures 9 to 28, unless otherwise indicated.
WARNING
To avoid personal injury or property damage caused by cylinder fracture as a result of piston impact, install the stem
connector securely before supplying pressure to the positioner. Use only a regulator-controlled air supply to move the
actuator piston so that you can install the stem connector. Do not use the positioner to move the actuator piston before
installing the stem connector.
Always wear protective gloves, clothing, and eyewear when performing any installation operations to avoid personal
injury.
If installing into an existing application, also refer to the warning at the beginning of the Maintenance section in this
manual.
Check with your process or safety engineer for any additional measures that must be taken to protect against process
media.
To avoid personal injury or property damage caused by bursting of pressure‐retaining parts, be certain the cylinder
pressure or other pressure ratings do not exceed the limits listed in table 1. Use pressure‐limiting or pressure‐relieving
devices to prevent cylinder pressure or other pressures from exceeding these limits.
To avoid personal injury or equipment damage, use proper lifting and rigging practices while lifting the actuator or
valve/actuator assembly. For all mounting procedures use an adequately sized chain, sling, hoist, or crane to handle the

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actuator and any attached accessories and/or valve. Use caution during lifting and handling to prevent slippage, swinging,
faulty equipment connections, or sudden shock loads.
NOTICE
Special care must be taken when installing an actuator in a horizontal service orientation. To avoid cantilever loads on the
valve stem and yoke, it is the customer’s responsibility to ensure proper support for a horizontal actuator.
The actuator may be installed in any orientation, but normal installation is with the actuator vertical above the valve.
If using a manual override in double acting application, a bypass valve should be furnished, allowing balance the
pressure within both sides of the piston before operating the manual override.
If using a manual handpump, the handpump must be installed vertical above the valve (see figure 7).
If the supply source is capable of exceeding the maximum actuator operating pressure or instrument supply pressure,
appropriate steps must be taken during installation to protect the instrument and all connected equipment against
overpressure.
When an actuator and control valve are shipped together as a control valve assembly, the actuator is normally
mounted on the valve. Follow the valve instructions when installing the valve in the pipeline. If the actuator is shipped
separately or if it is necessary to mount the actuator on the valve, perform the actuator mounting procedures in this
instruction manual. Refer to the individual product instruction manuals for the installation or mounting of a FIELDVUE
DVC6200 digital valve controller.
If the actuator is being installed without a positioner, the cylinder loading pressures should be supplied through a
4-way solenoid valve or a switching valve.
Pressure connections are located on top of the pneumatic cylinder end flange (key 2210) and on the side of the
pneumatic cylinder head flange (key 2201).
D The supply pressure medium should be clean, dry filtered air. If the supply source is capable of exceeding the
maximum actuator operating pressure or positioner supply pressure, appropriate steps must be taken during
installation to protect the positioner and all connected equipment against over pressurization.
D The control valve should be located where it will be accessible for servicing. Space should be left above and below
the control valve to permit removal of the actuator and valve plug.
Actuator Earth Grounding
All Fisher 785C series actuators are provided with a threaded actuator earth grounding interface on the yoke (spool)
for the earth connection as shown in the figure 3.
Note
Proper connection to the earth grounding interface is required for compliance with ATEX regulations.

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Figure 3. Actuator Earth Grounding Interface
ACTUATOR EARTH
GROUND INTERFACE
Three‐Way Valve Applications Note
In three-way valve applications where the actuator fully strokes at a frequency of once per minute or faster, and the
stroking speed is rapid (less than 0.5 seconds per stroke), there is a possibility that the stem can fracture at the plug if
the actuator cylinder pressure is greater than 5.5 bar (80 psig). This can cause loss of control of process fluid and
further damage to the actuator. Considerations should be given to the use of high-strength, fatigue-resistant stem
materials in these applications.
WARNING
To avoid loss of control of process fluid and subsequent personal injury or property damage caused by bursting of
pressure‐retaining parts, be sure the cylinder pressure does not exceed 5.5 bar (80 psig) in high cycle‐rate, fast stroking
speed, three‐way valve applications.
Manual Override
The actuator can be equipped with a manual override. The manual override can be executed with a Manual Handwheel
or a Manual Hydraulic Pump which can operate the actuator.

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Manual Handwheel Operation
If manual operation is required for actuator sizes 280, 335, and 385 a manual handwheel should be equipped as
standard construction.
NOTICE
To avoid damage to actuator parts and difficult operation of actuator handwheels, open the bypass valve before using a
handwheel. Do not disengage the handwheel if the spring thrust is not balanced by pneumatic load for spring return
actuator.
A bypass assembly is furnished only when an actuator with manual override is specified, see figure 4. The bypass
assembly allows the pressure to equalize on either side of the actuator piston, so that the manual override can be used
to position the control valve. Flow through the bypass tubing is controlled by an angle needle valve, which is operated
manually. This valve should be closed when air pressure is being used to operate the actuator.
Figure 4. Bypass Valve Examples for Double-Acting 785C Actuator with Manual Override
GH14579, sheet 1
ACTUATOR,
SPRING RETURN
GH14579, sheet 3
ACTUATOR,
SPRINGLESS

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The following steps reference figure 5 and 6. Refer to table 6 for handwheel specifications.
HANDLE
Figure 5. Top Mounted Manual Handwheel
HANDWHEEL INSTRUCTION
WARNING
Figure 6. Top Mounted Manual Handwheel
Engagement/Disengagement Instruction Label
ENGAGED
DISENGAGED
TO OPEN
TO CLOSE
1. Engage the manual override by rotating its handle, reference figure 5. Note that there is only one position (at 360°
rotation of the handwheel) where the handle will correctly engage the manual operation. To reach that position
during the rotation of the handle, slowly rotate the handwheel until the correct position, as indicated on the
warning plate shown in figure 5.
2. Turn the handwheel of the manual override clockwise to close, or counterclockwise to open, as indicated on the
instruction label shown in figure 6.
3. Check the correct operation of the actuator by monitoring the movement of the travel indicator.
4. Once manual operation is completed, the bypass valve should be close and remain shut off during pneumatic
supply air operation.
5. Ensure the unbalanced thrust, such as spring return actuator spring thrust, is balanced by applying a pneumatic
load and disengage the manual handwheel by rotating the handle as shown on the instruction plate. This allows the
actuator to be operated by the pneumatic supply.
If it is necessary to keep the valve in its position and if the pneumatic supply is not restored yet, do not disengage
the handwheel.
For spring return actuator, if it is not necessary to keep the valve in its position and if the pneumatic supply is not
restored yet, in order to disengage the handwheel, turn the handwheel to the end which spring would fully release
without applying any thrust to the handwheel, to get an easy disengagement of the handwheel.

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Manual Hydraulic Handpump Operation
If manual operation is required, actuator sizes 435, 485, 535, 585, 635, and 685 should be equipped with a manual
handpump as standard construction.
Note
The manual handpump control unit must be installed in vertical up direction per figure 7. For application requiring actuator
horizontal installation, a special design handpump support and hydraulic tubing must be used to install handpump in vertical up
direction per figure 7. Contact your Emerson sales office for further information of manual handpump for actuator horizontal
installation.
Figure 7. Handpump Orientation
HANDPUMP CONTROL UNIT
MUST BE INSTALLED IN
VERTICAL UPRIGHT DIRECTION
GRAVITY
DIRECTION
GH15114 sheet 1
A bypass assembly is furnished only when an actuator with manual override is specified. The bypass assembly allows
the pressure to equalize on either side of the actuator piston, so that the manual override can be used to position the
control valve. Flow through the bypass tubing is controlled by an angle needle valve, which is operated manually. This
valve should be closed when supply pressure is being used to operate the actuator.
The following steps are referenced in figures 8, 9, and 10. Refer to table 7 for handpump specifications and figures 11
through 17 for handpump schematics and more detail instructions.
1. Select “Manual Opening” or “Manual Closing” by rotating the Engagement/Disengagement handle as indicated on
the instruction plate from pneumatic operation “REMOTE” mode.
2. Actuate the handpump according to figure 11 through 17 handpump schematic detail instructions until the desired
position of the actuator is reached.
3. Check the correct operation of the actuator through the visual travel indicator.

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4. Once manual operation is completed, rotate the handle to the “REMOTE” position, as indicated on the instruction
plate in figure 8, to disengage the manual operator. Follow figure 11 through 17 handpump schematic detail
instructions to allow the “REMOTE “operation with the pneumatic supply. Once manual operation is completed, the
bypass valve should be close and remain shutoff during pneumatic supply air operation.
Figure 8. Manual Hydraulic Handpump Engagement/Disengagement Instructions Plate
Figure 9. Manual Hydraulic Handpump Typical Constructions
(Design Varies for Different Actuator Type and Handpump Type)
STOP VALVE FOR FAST STROKE TYPE MHQ
HANDPUMP
HANDLE
STOP VALVE
(MULTIPLE POSITIONS SHOWING)
ENGAGEMENT AND
DISENGAGEMENT
HANDLE

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Figure 10. Manual Hydraulic Handpump Typical Constructions
(Design Varies for Different Actuator Type and Handpump Type)
STOP VALVE FOR FAST STROKE TYPE MHQ
STOP VALVE
(MULTIPLE POSITIONS SHOWING)
HANDPUMP
HANDLE
Table 9. Handpump Schematics(1)
Actuator Type Handpump Type Schematics Figure
785C Spring Return Rod Extend (Fail Down)
Single- or Double-Acting
Fast Stroke MHQ 11
Standard Stroke MHP 12
785C Spring Return Rod Extend (Fail Up)
Single- or Double-Acting
Fast Stroke MHQ 13
Standard Stroke MHP 14
785C Springless, Double-Acting Standard Stroke MHP 15
Fast Stroke MHQ 16 or 17
1. Notice the 785C Spring Return schematics drawn as single-acting would also work for double-acting.

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Figure 11. Handpump Schematic: Fast Stroke MHQ Handpump for 785C Spring Return Rod Extend (Fail Down),
Single- or Double-Acting
PNEUMATIC SUPPLY
PNEUMATIC REMOTE CONTROL TO OPEN
PRESSURIZED PERMANENTLY THE PNEUMATIC SUPPLY LINE.
PNEUMATIC REMOTE CONTROL TO CLOSE
DE-PRESSURIZED THE PNEUMATIC SUPPLY LINE.
EMERGENCY MANUAL OPERATION
IN CASE OF PNEUMATIC SUPPLY FAILURE, CLOSE THE STOP VALVE 351B,
SELECT BY THE VALVE “5-D” THE OPENING OPERATION AND ACTUATE
THE HAND PUMP “5-P”.
AT THE END OF THE OPENING OPERATION CLOSE THE VALVE 351A.
NOTE: THE VALVE “5-D” MUST BE IN “REMOTE CONTROL” POSITION AND
THE STOP VALVES 351A AND 351B MUST BE OPEN TO ALLOW THE
OPERATION WITH PNEUMATIC SUPPLY.
1SINGLE-ACTING SPRING RETURN PNEUMATIC LINEAR ACTUATOR
3HYDRAULIC CYLINDER
5MANUAL OVERRIDE
R — RELIEF VALVE
P — HAND PUMP
D — HAND OPERATED DIRECTIONAL CONTROL VALVE
351STOP VALVE
395RELIEF VALVE
CLOSE

Instruction Manual
D104483X012
785C Actuator
May 2022
16
Figure 12. Handpump Schematic: Standard Stroke MHP Handpump for 785C Spring Return Rod Extend (Fail Down),
Single- or Double-Acting
PNEUMATIC SUPPLY
PNEUMATIC REMOTE CONTROL TO OPEN
PRESSURIZED PERMANENTLY THE PNEUMATIC SUPPLY LINE.
PNEUMATIC REMOTE CONTROL TO CLOSE
DE-PRESSURIZED THE PNEUMATIC SUPPLY LINE.
EMERGENCY MANUAL OPERATION
IN CASE OF PNEUMATIC SUPPLY FAILURE, SELECT BY THE VALVE “5-D”
THE OPENING OPERATION AND ACTUATE THE HAND PUMP “5-P”.
AT THE END OF THE OPENING OPERATION CLOSE THE VALVE 351.
NOTE: THE VALVE “5-D” MUST BE IN “REMOTE CONTROL” POSITION
AND THE STOP VALVES 351 AND MUST BE OPEN TO ALLOW THE
OPERATION WITH PNEUMATIC SUPPLY.
1SINGLE-ACTING SPRING RETURN PNEUMATIC LINEAR ACTUATOR
3HYDRAULIC CYLINDER
5MANUAL OVERRIDE
R — RELIEF VALVE
P — HAND PUMP
D — HAND OPERATED DIRECTIONAL CONTROL VALVE
351STOP VALVE
395RELIEF VALVE
CLOSE

Instruction Manual
D104483X012
785C Actuator
May 2022
17
Figure 13. Handpump Schematic: Fast Stroke MHQ Handpump for 785C Spring Return Rod Retract (Fail Up),
Single- or Double-Acting
PNEUMATIC SUPPLY
PNEUMATIC REMOTE CONTROL TO CLOSE
PRESSURIZED PERMANENTLY THE PNEUMATIC SUPPLY LINE.
PNEUMATIC REMOTE CONTROL TO OPEN
DE-PRESSURIZED THE PNEUMATIC SUPPLY LINE.
EMERGENCY MANUAL OPERATION
IN CASE OF PNEUMATIC SUPPLY FAILURE, CLOSE THE STOP VALVE
351B, SELECT BY THE VALVE “5-D” THE CLOSING OPERATION AND
ACTUATE THE HAND PUMP “5-P”.
AT THE END OF THE CLOSING OPERATION CLOSE THE VALVE 351A.
NOTE: THE VALVE “5-D” MUST BE IN “REMOTE CONTROL” POSITION
AND THE STOP VALVES 351A AND 351B MUST BE OPEN TO ALLOW
THE OPERATION WITH PNEUMATIC SUPPLY.
1SINGLE-ACTING SPRING RETURN PNEUMATIC LINEAR ACTUATOR
3HYDRAULIC CYLINDER
5MANUAL OVERRIDE
R — RELIEF VALVE
P — HAND PUMP
D — HAND OPERATED DIRECTIONAL CONTROL VALVE
351STOP VALVE
395RELIEF VALVE
OPEN

Instruction Manual
D104483X012
785C Actuator
May 2022
18
Figure 14. Handpump Schematic: Standard Stroke MHP Handpump for 785C Spring Return Rod Retract (Fail Up),
Single-or Double-Acting
PNEUMATIC SUPPLY
PNEUMATIC REMOTE CONTROL TO CLOSE
PRESSURIZED PERMANENTLY THE PNEUMATIC SUPPLY LINE.
PNEUMATIC REMOTE CONTROL TO OPEN
DE-PRESSURIZED THE PNEUMATIC SUPPLY LINE.
EMERGENCY MANUAL OPERATION
IN CASE OF PNEUMATIC SUPPLY FAILURE, SELECT BY THE VALVE “5-D”
THE CLOSING OPERATION AND ACTUATE THE HAND PUMP “5-P”.
AT THE END OF THE CLOSING OPERATION CLOSE THE VALVE 351.
NOTE: THE VALVE “5-D” MUST BE IN “REMOTE CONTROL” POSITION
AND THE STOP VALVES 351 MUST BE OPEN TO ALLOW THE OPERATION
WITH PNEUMATIC SUPPLY.
1SINGLE-ACTING SPRING RETURN PNEUMATIC LINEAR ACTUATOR
3HYDRAULIC CYLINDER
5MANUAL OVERRIDE
R — RELIEF VALVE
P — HAND PUMP
D — HAND OPERATED DIRECTIONAL CONTROL VALVE
351STOP VALVE
395RELIEF VALVE
OPEN

Instruction Manual
D104483X012
785C Actuator
May 2022
19
Figure 15. Handpump Schematic: Standard Stroke MHP Handpump for 785C Springless Double-Acting
PNEUMATIC SUPPLY
TO CLOSE
PNEUMATIC REMOTE CONTROL TO OPEN
PRESSURIZE THE OPENING PNEUMATIC SUPPLY LINE.
THE OPENING TIME IS ADJUSTABLE BY THE FLOW REGULATOR 5-Fa.
PNEUMATIC REMOTE CONTROL TO CLOSE
PRESSURIZE THE OPENING PNEUMATIC SUPPLY LINE.
THE CLOSING TIME IS ADJUSTABLE BY THE FLOW REGULATOR 5-Fc.
EMERGENCY MANUAL OPERATION
DE-PRESSURIZE BOTH PNEUMATIC SUPPLY LINE AND OPEN
BOTH STOP VALVES 351A/B.
SELECT BY THE VALVE “D” THE OPENING OR CLOSING OPERATION
AND ACTUATE THE HAND PUMP “P”.
CLOSE THE STOP VALVE 351A TO KEEP THE ACTUATOR IN OPEN
POSITION OR CLOSE THE STOP VALVE 351B TO KEEP THE
ACTUATOR IN CLOSED POSITION.
NOTE: THE VALVE “D” MUST BE IN “REMOTE CONTROL” POSITION
AND THE STOP VALVES 351A AND 351B MUST BE OPEN TO ALLOW
THE OPERATION WITH GAS SUPPLY.
1DOUBLE-ACTING PNEUMATIC LINEAR ACTUATOR
3HYDRAULIC CYLINDER
5MANUAL OVERRIDE
R — RELIEF VALVE
P — HAND PUMP
D — HAND OPERATED DIRECTIONAL CONTROL VALVE
Fa — UNIDIRECTIONAL FLOW REGULATOR (OPENING OPERATION)
Fc — UNIDIRECTIONAL FLOW REGULATOR (CLOSING OPERATION)
351STOP VALVE
395RELIEF VALVE
CLOSE
PNEUMATIC SUPPLY
TO OPEN

Instruction Manual
D104483X012
785C Actuator
May 2022
20
Figure 16. Handpump Schematic: Fast Stroke MHQ Handpump Type 1 for 785C Springless Double-Acting
PNEUMATIC SUPPLY
TO CLOSE
PNEUMATIC REMOTE CONTROL TO OPEN
PRESSURIZE THE OPENING PNEUMATIC SUPPLY LINE.
THE OPENING TIME IS ADJUSTABLE BY THE FLOW REGULATOR 5-Fa.
PNEUMATIC REMOTE CONTROL TO CLOSE
PRESSURIZE THE OPENING PNEUMATIC SUPPLY LINE.
THE CLOSING TIME IS ADJUSTABLE BY THE FLOW REGULATOR 5-Fc.
EMERGENCY MANUAL OPERATION
DE-PRESSURIZE BOTH PNEUMATIC SUPPLY LINE AND OPEN BOTH
STOP VALVES 351C AND OPEN BOTH STOP VALVES 351A/B.
SELECT BY THE VALVE “D” THE OPENING OR CLOSING OPERATION
AND ACTUATE THE HAND PUMP “P”.
CLOSE THE STOP VALVE 351A TO KEEP THE ACTUATOR IN OPEN
POSITION OR CLOSE THE STOP VALVE 351B TO KEEP THE
ACTUATOR IN CLOSED POSITION.
NOTE: THE VALVE “D” MUST BE IN “REMOTE CONTROL” POSITION
AND THE STOP VALVES 351 MUST BE OPEN TO ALLOW THE
OPERATION WITH GAS SUPPLY.
1DOUBLE-ACTING PNEUMATIC LINEAR ACTUATOR
3HYDRAULIC CYLINDER
5MANUAL OVERRIDE
R — RELIEF VALVE
P — HAND PUMP
D — HAND OPERATED DIRECTIONAL CONTROL VALVE
Fa — UNIDIRECTIONAL FLOW REGULATOR (OPENING OPERATION)
Fc — UNIDIRECTIONAL FLOW REGULATOR (CLOSING OPERATION)
351STOP VALVE
395RELIEF VALVE
CLOSE
PNEUMATIC SUPPLY
TO OPEN