IMI SC Series User manual

SC/VHS - VALVE HYDRAULIC
ACTUATOR
Single acting stainless steel version type
INSTRUCTION MANUAL 5021

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STI S.r.l. – Via Dei Caravaggi 15, 24040 Levate (BG) – ITALY www.imi-critical.com
Manual 5021, rev. 00 10/2015 – SC/VHS - i -
Date Revision Description Compiled Approved
05/10/2016 00 Issue M. Bozzarelli E. Montagna
STI S.r.l has taken every care in collecting and verifying the documentation contained in this Instruction
Manual. The information herein contained are reserved property of STI S.r.l.

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STI S.r.l. – Via Dei Caravaggi 15, 24040 Levate (BG) – ITALY www.imi-critical.com
Manual 5021, rev. 00 10/2015 – SC/VHS - ii -
INDEX
1 GENERAL INFORMATION .................................................................................................................. 1
1.1 GENERAL WARNINGS ........................................................................................................................ 1
1.2 GENERALITIES .................................................................................................................................. 1
1.3 MANUFACTURER ............................................................................................................................... 1
1.4 TERMS AND CONDITIONS ................................................................................................................... 1
1.5 MANUFACTURER’S LIABILITY ............................................................................................................. 1
1.6 APPLICABLE STANDARDS AND DIRECTIVES ........................................................................................ 2
1.7 SYMBOLOGY USED ........................................................................................................................... 2
2 DEVICE DESCRIPTION ....................................................................................................................... 3
2.1 GENERAL DESCRIPTION .................................................................................................................... 3
2.2 IDENTIFICATION OF THE MAIN PARTS ................................................................................................. 3
2.3 ACTUATOR CODING DESCRIPTION ...................................................................................................... 4
3 TECHNICAL DATA ............................................................................................................................... 5
4 IDENTIFICATION PLATE ..................................................................................................................... 5
5 INSTALLATION .................................................................................................................................... 6
5.1 TRANSPORT ..................................................................................................................................... 6
5.2 RECEPTION ...................................................................................................................................... 7
5.3 STORAGE ......................................................................................................................................... 7
5.4 REQUIREMENTS OF STABILITY ........................................................................................................... 7
5.5 INTERFACE DOCUMENT AND DIMENSIONAL DRAWING ........................................................................... 7
5.6 INSTALLATION ................................................................................................................................... 8
5.7 DISASSEMBLING ............................................................................................................................. 11
6 OPERATION AND USE ...................................................................................................................... 12
6.1 OPERATION DESCRIPTION ............................................................................................................... 12
6.2 INTENDED USE ................................................................................................................................ 12
6.3 REASONABLY FORESEEABLE MISUSE ............................................................................................... 13
6.4 OPERATING LIMITS .......................................................................................................................... 13
6.5 RESIDUAL RISKS ............................................................................................................................ 13
7 INSTRUCTIONS FOR THE OPERATOR ........................................................................................... 14
7.1 START UP ...................................................................................................................................... 14
7.2 STROKE ADJUSTMENT ..................................................................................................................... 15
8 MAINTENANCE .................................................................................................................................. 16
8.1 PERIODIC INSPECTIONS .................................................................................................................. 16
8.2 SPECIAL MAINTENANCE ................................................................................................................... 17
8.3 REPAIRS ........................................................................................................................................ 20
8.4 REASSEMBLING .............................................................................................................................. 20
8.5 MECHANISM LUBRICATION............................................................................................................... 21
8.6 HYDRAULIC FLUID ........................................................................................................................... 21
9 TROUBLESHOOTING ........................................................................................................................ 22
10 PARTS LIST GENERAL ASSEMBLY ............................................................................................ 23
11 SPARE PARTS ............................................................................................................................... 27
12 DECOMMISSIONING ...................................................................................................................... 28
13 DECLARATION OF INCORPORATION ......................................................................................... 30

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Manual 5021, rev. 00 10/2015 – SC/VHS - 1 -
1 GENERAL INFORMATION
1.1 General Warnings
Important This Instruction Manual is an integral part of the machine, it should be carefully
read before carrying out any operation and it should be kept for future
references.
This Instruction Manual covers the SC/VHS actuators in the base version without
any accessories and/or control panel.
In case accessories and/or control panel are foreseen mounted on the actuator
an additional Section to this Instruction Manual will be attached to the specific
actuator.
This Instruction Manual is realized in accordance with the Directive 2006/42/CE.
1.2 Generalities
STI S.r.l. actuators are conceived, manufactured and controlled according to the Quality Control System
in compliance with EN ISO 9001 International Standard.
1.3 Manufacturer
With respect to Machinery Directive 2006/42/EC the Manufacturer of the described SC/VHS actuator
series, is STI S.r.l. as specified on the machinery label.
Address : STI S.r.l.
Via Dei Caravaggi, 15
24040 Levate (Bergamo) – Italy
1.4 Terms and conditions
STI S.r.l. guarantees each single product to be free from defects and to conform to current goods
specifications. The warranty period is one year from the date of installation by the first user, or eighteen
months from the date of shipment to the first user, whichever occurs first.
The warranty does not cover special products or components not covered by warranty in their turn by
subcontractors. No warranty is given for products which have been subject to improper storage, improper
installation, misuse, or corrosion, or which have been modified or repaired by unauthorised personnel.
Repair work due to improper use will be charged at standard rates.
1.5 Manufacturer’s Liability
STI S.r.l. declines all liability in the event of:
- use of the actuator in contravention of local safety at work legislation
- incorrect installation, disregard or incorrect application of the instructions provided on the actuator
nameplate and in this manual
- modifications without STI’s authorisation
- work done on the unit by unqualified or unsuitable persons.

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Manual 5021, rev. 00 10/2015 – SC/VHS - 2 -
1.6 Applicable Standards and Directives
- EN ISO 12100:2010: Safety of machinery - General principles for design. Risk asses and risk
reduction.
- 2006/42/EC Machinery Directive.
- 97/23/EC Pressure Equipments Directive (PED)
- 2006/95/EC Directive for Low Voltage Equipment (LV)
- 2004/108/EC Directive relating to the Electromagnetic Compatibility (EMC)
- 94/9/CE Directive concerning equipment for use in potentially explosive atmospheres (ATEX)
1.7 Symbology Used
1.7.1 Signs of warning
Be careful where these symbols are shown, they indicate a potentially hazardous situation and they
warn that if the steps are not properly performed, MAY RESULT CAUSING serious injury, death or
long-term risks to the health of exposed persons.
1.7.2 Sings of obbligation
General
obligation (with
the possible
supplementary
signboard)
Must wear
protective
clothing.
Obligation to
wear
protective
footwear.
Is required to
wear a helmet.
Is required to
protect the
eyes.
Obligation to
protect your
hearing.
GENERAL DANGER DANGER POWER SUPPLY CRUSHING HAZARD

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Manual 5021, rev. 00 10/2015 – SC/VHS - 3 -
2 DEVICE DESCRIPTION
2.1 General Description
SC/VHS single acting hydraulic actuators are suitable for the operation of linear valves for ON-OFF and
modulating heavy-duty service.
The actuator is made up of a customized adapting valve and an hydraulic cylinder which is necessary to
transmit the linear motion for the valve operation.
The linear stroke of the valve is adjustable by means of the external mechanical stop for upward position
and by the adjustment of the coupling of valve stem to actuator joint for the downward position.
The actuator pedestal has a flange with threaded holes to fix the actuator to the valve.
STI can offer different types of control system according to specific Customer's requirements.
2.2 Identification of the Main Parts
The SC/VHS actuator is composed by the following main parts:
1) Adapting valve assembly
2) Hydraulic cylinder
3) Stop setting screw kit
Fig. 1: Main parts for SC/VHS actuator series

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Manual 5021, rev. 00 10/2015 – SC/VHS - 4 -
2.3 Actuator coding description
-
V
SCVHS
yyy
xxx
H
HW
HWR
HP
Manual handwheel with reduction
Hydraulic hand pump
CYLINDER DIAMETER
Accessories
Manual handwheel
Stroke
Hyyy xxx
-
V
Version
Single acting

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Manual 5021, rev. 00 10/2015 – SC/VHS - 5 -
3 TECHNICAL DATA
DATA
Supply medium Hydraulic fluid (see Section 8.6)
Operating temperature ranges Standard : -20°C +100°C
Optional : -60°C +100°C
Cylinder design pressures Up to 350 bar (special version on request)
Operating pressure range Data are available on actuator nameplate (depending
on customer requirements and specifications.)
Max operating thrust Data are available on actuator nameplate
Applications On-Off
Modulating service (on request)
The nameplate fastened on the actuator contains the main actuator operating condition.
It is forbidden to modify the information and the marks without previous written authorization by STI S.r.l.
4 IDENTIFICATION PLATE

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Manual 5021, rev. 00 10/2015 – SC/VHS - 6 -
5 INSTALLATION
5.1 Transport
Important: The lifting and handling should be made by qualified staff and in compliance
with the laws and provisions in force.
Warning: Lift the actuator as shown in Fig.2.
The fastening points are appropriate for the lifting of the actuator alone and not for
the valve + actuator assembly.
Warning: Avoid that during the handling, the actuator passes above the staff.
The actuator should be handled with appropriate lifting means.
The weight is reported on the delivery bill and on overall-dimensions drawings
furnished with the documents accompanying the actuator.
For base actuator dimensions and weights please consult www.stiactuation.com
Fig. 2 – Lifting points for SC/VHS actuator series
Important: Not performing the following procedures will invalidate the product guarantee.

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Manual 5021, rev. 00 10/2015 – SC/VHS - 7 -
5.2 Reception
- Check that the model, the serial number of the actuator and the technical data reported on the
identification plate correspond with those of order confirmation (Sect. 4).
- Check that the actuator is equipped with the fittings as provided for by order confirmation.
- Check that the actuator was not damaged during transportation: if necessary renovate the painting
according to the specification reported on the order confirmation.
- If the actuator is received already assembled with the valve, its settings have already been made at
the factory.
- If the actuator is delivered separately from the valve, it is necessary to check, and, if required, to
adjust, the settings of the mechanical stops (Sect. 7.2).
5.3 Storage
All the actuators SC/VHS leave the factory in perfect condition. Performances of each unit are guaranteed
by individual test and data reported on a specific test certificate issued for each unit.
In order to maintain these characteristics until the SC/VHS actuator is installed on site, proper attention
must be observed for preservation during the storage period.
If the actuator needs storage, before installation follow these steps:
- Place it on a wood surface pallet or on metallic support, so that they are not in direct contact with the
ground, in order not to deteriorate the area of valve coupling, later it must be packed with appropriate
covering.
- Make sure that plastic plugs are present on the hydraulic and electrical connections (if present).
- Check that the limit switch box (if any) is properly closed.
If the storage is long-term or outdoor:
- Keep the actuator protected from direct weather conditions.
- Replace plastic plugs of hydraulic and electrical connections (if any) with metal plugs that guarantee
perfect tightness.
- Coat with oil, grease or protection disc, the valve coupling area.
- Periodically operate the actuator (Sect.6).
5.4 Requirements of Stability
- Conditions in which the machinery meets the requirement of stability during use, transportation,
assembly, dismantling when out of service, testing or foreseeable breakdowns, are shown in Fig.2.
- The actuator must be put, with extreme caution, in a right position on a plane surface and with
adapted capacity to the load to support.
- Do not use actuator eye bolts lifting of valve-actuator package.
- Concerning the requirement of stability during installation and disassembling it ‘s possible to refer to
the next chapters 5.6 and 5.7.
5.5 Interface document and dimensional drawing
- Hydraulic diagrams, wiring diagrams and dimensional drawing are furnished with document
accompanying the actuator.

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Manual 5021, rev. 00 10/2015 – SC/VHS - 8 -
5.6 Installation
Warning: Before proceeding with any Installation the following instructions must be
respected:
- Always wear protective clothing, gloves, and eyewear to prevent personal
injury.
- Use the lifting point foreseen on the actuator to move the actuator: if
different instructions are not well specified the lifting points foreseen on
the actuator must be used only to move the actuator.
- Check with your process or safety engineer for any additional measures
that must be taken to protect against process media.
5.6.1 Checks to be performed before installation
If the SC/VHS actuator is purchased separately, proceed as follows before assembling it onto the valve:
1) Check that the coupling dimensions of the actuator/coupling block flange and stem meet the
specified coupling dimensions.
2) Prepare the necessary tools for the assembly and setting of the unit.
3) Check that the outer surface of the actuator is free from dust and dirt.
4) Clean the actuator flange and remove anything that might prevent a perfect adherence to the
actuator/coupling block flange and joint especially all traces of grease.
5.6.2 Assembling of the actuator on the valve
The actuator can be assembled on top of the valve flange by using the lifting eyelets installed on
hydraulic cylinder flange.
The assembly position of the actuator, with reference to the valve, must comply with the plant
requirements
To assemble the actuator onto the valve proceeds as follows:
 Check that the coupling dimensions of the valve flange and stem, or of the
relevant extension, meet the actuator coupling dimensions (valve stem and
flange).
 To make easier the assembly, the valve stem has to be in perfect vertical
position.
 Disassemble the two halves of actuator shell joint (Fig. 7.2) by unscrewing
the retaining screws.
 Lift the actuator by utilizing the proper lifting eyelets, and unscrew the nuts
and the stud bolts from the actuator pedestal.
 Assemble the actuator onto the valve, and arrange it in its correct vertical
position proper to connection between valve stem and actuator cylinder rod.
 Connect the valve stem and the actuator stem in their place inside into the
shell joint and refit the second half, tighten the screws fixing common
 Screw the stud bolts into the actuator pedestal flange, and screw the nuts on
the stud bolts.
 Tighten according to the nut size torque requirements.
Fig. 3

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Manual 5021, rev. 00 10/2015 – SC/VHS - 9 -
Important To guarantee the correct transmission from the actuator to valve stem
without phenomena of slip it is important to remove any trace of oil and/or
grease from the mating surfaces of valve and actuator or bracket and tighten
the nuts fixing the bolts with the torque specified into the following Table 1
Table 1
Threading Tightening torque (Nm) Threading Tightening torque (Nm)
M8 20 M24 550
M10 40 M27 800
M12 70 M30 1200
M14 110 M33 1400
M16 150 M36 1800
M20 300
The torque values in Table 1 have been calculated considering the materials ASTM A320 grade L7/ASTM
A193 grade B7 for screws or tie rods and ASTM A194 grade 4 for the nuts.
Alternative bolting permitted i.e. ASTM A193 B8M (or B8M3) for tie rods and ASTM A194 Gr.8M for the
nuts, provided that yield strength of screws or tie rods is over than 450 Mpa.
5.6.3 Hydraulic Connections
Warning
Check that the values of hydraulic supply available are compatible with those reported on
the identification plate of the actuator.
Use pipes and connections appropriate as for type, rating, material and dimensions.
The connection should be made by qualified staff.
- Properly deburr the ends of rigid pipes.
- Properly clean the interior of pipes sending through them plenty of the supply fluid used in the system.
- Carry out the flushing operation before assembling the pipes.
- Mould and fasten the connection pipes so that no irregular strains at entries or loosening of threaded
connections occur.
- Make the connections according to the operating diagram.
- Check the absence of leakages from hydraulic connections. If necessary tighten the nuts of the pipe-
fittings.

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Manual 5021, rev. 00 10/2015 – SC/VHS - 10 -
5.6.4 Electrical Connections (If any)
Warning
Before carrying out electrical connections, switch off any power and control lines.
Use components appropriate as for type, material and dimensions.
The connections should be made by qualified staff.
- Introduce connection cables.
- Make the connections in compliance with applicable wiring diagrams on the documentation supplied.
- Screw the cable gland.
- Replace the plastic plugs of unused entries with metal plugs.
5.6.5 Earting connection
If the hearting connection is not guaranteed trough mechanical parts where actuator is mounted, it is
necessary ensure a directly hearting connection on provided point of actuator.

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Manual 5021, rev. 00 10/2015 – SC/VHS - 11 -
5.7 Disassembling
Fig. 4 – Disassembling of the actuator
Warning Before starting the disassembly operations it is mandatory to disconnect the
hydraulic power and to exhaust the cylinder and any other pressure retaining
component mounted on the actuator.
Before removing the screws between actuator and valve or adaptor flange or mounting
bracket, the actuator should be connected with appropriate lifting means. Lift the actuator
as shown in Fig.3. The lifting points are appropriate for handling the actuator alone and
not for the valve + actuator assembly.
Screws to remove

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Manual 5021, rev. 00 10/2015 – SC/VHS - 12 -
6 OPERATION AND USE
6.1 Operation description
The SC/VHS series is hydraulic actuator designed for on-off and control service and is applicable over a
wide range of pressure, temperatures and environments.
Depending which hydraulic cylinder is pressurized or not, the valve either opens or closes by the action of
the piston (cylinder pressurized) or the spring (cylinder not pressurized).
6.2 Intended use
The machinery covered in this Instruction Manual is single acting hydraulic SC/VHS actuator
series designed to operate a linear industrial valve (globe valves, gate valves, choke valves, ..) for
ON-OFF or modulating heavy duty service.
This SC/VHS actuator is produced by STI srl [Manufacturer] and identified by a label with a product
designation code. STI srl will not be liable for any possible damage or physical injury resulting from use in
other than the designated applications or by lack of care during installation, operation, adjustment and
maintenance of the machine. Such risks lie entirely with the user. Depending on the specific working
conditions, additional precautions may be requested. Considering that STI srl has no direct control over
particular applications, operation or maintenance conditions, it is the operator’s responsibility to comply
with all applicable safety rules. Please inform STI srl urgently if you face unsafe situations not described
in this Instruction Manual. It is the sole responsibility of the operator to ensure that the local health and
safety regulations are adhered to.
SC/VHS actuator is designed in accordance with the applicable International Rules and Specifications,
but the following Regulations must be observed in any case:
- the general and safety regulations
- the plant specific regulations and requirements
- the proper use of personal and protective devices (glasses, clothing, gloves, etc)
- the proper use of tools, lifting and transport equipment.
Warning
It is severely forbidden to use the SC/VHS actuators series for purpose or
application other than those for which it was designed and here above specified.

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Manual 5021, rev. 00 10/2015 – SC/VHS - 13 -
6.3 Reasonably foreseeable misuse
A short list of reasonably foreseeable misuse :
- Installation in ambient with not planned conditions: i.e. climatic conditions different from the specified
conditions;
- Insert incorrect fluid into the system;
- Supply pressure out of required range;
- Lifting of the actuator with valve through eye bolts.
6.4 Operating limits
Operating conditions are described in paragraph 3, the nameplate fastened on the actuator contains the
main actuator operating condition for the specified application.
Warning
It is severely forbidden to use the actuator under conditions other than those
provided on the nameplate.
6.5 Residual Risks
Warning
The actuator has parts under pressure. Use the due caution.
Use individual protections provided for by the laws and provisions in force.
- Risk due to movements of loads during load displacements, assemblage and maintenance servicing.
- Electrical risk due to an incorrect application of the instruction.
- Crushing during assemblage and maintenance servicing.
- Extreme metal temperature at high (over than 80°C) or very low values as consequence of ambient
temperature as to be considered as a risk of person injury in case of contact.
- Emissions of hazardous substances where special medium is used as motive energy. (please refer
to material safety data sheet of the hydraulic fluid if it is different to those fluids shown in paragraph
8.6 )

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Manual 5021, rev. 00 10/2015 – SC/VHS - 14 -
7 Instructions for the operator
7.1 Start Up
During the start-up of the actuator, proceed as follows:
- Check that the pressure and quality of the hydraulic fluid (filtering degree,….) are as prescribed.
- Check that the feed voltage values of the electric components (solenoid valve coils, micro-switches,
pressure switches, etc.) are as prescribed.
- Connect the actuator to the hydraulic feed line with fittings and tubing in accordance to project
specifications. They must be sized correctly in order to guarantee the necessary oil flow for the
operation of the actuator, with pressure drops not exceeding the maximum allowable value. The shape
of the connecting piping must not cause excessive stress to the inlets of the actuator. The piping must
be suitably fastened so as not to cause excessive stress or loosening of threaded connections, if the
system undergoes strong vibrations.
- Every precaution must be taken to ensure that any solid or liquid contaminants, which may be present
in the hydraulic pipework to the actuator, are removed to avoid possible damages to the unit or loss of
performance.
- The inside of the pipes used for the connections must be well-cleaned before use: wash them with
suitable substances and blow through them with oil or nitrogen. The ends of the tubes must be well
deburred and cleaned.
- Connect the electrical feed, control and signal lines to the actuator, by linking them up with the
terminal blocks of the electrical components. In order to do this, the housing covers must be removed
without damaging the coupling surfaces, the O-rings or the gaskets.
- Remove the plugs from the cable entries.
- For electrical connections use components (cable glands, cables, hoses, conduits) in line with project
and hazardous area requirements and codes applicable to the plant specifications (mechanical
protection and/or explosion proof protection).
- Screw the cable glands tightly into the threaded inlets, so as to guarantee the weatherproof and
explosion proof protection (if applicable).
- Insert the connection cables into the electrical enclosures through the cable glands, and connect the
cable wires to the terminals according to the applicable wiring diagram.
- If conduits are used, it is advisable to carry out the connection to the electrical enclosures by inserting
hoses so as not to cause anomalous stress on the housing cable entries.
- Replace the plastic plugs of the unused enclosure entries by metal ones, to guarantee perfect
weatherproof tightness and to comply with the explosion proof protection codes (where applicable).
Once the connections are completed:
- check that the actuator controls work properly (remote control, local control, emergency controls, etc.)
- operate the actuator and check that it functions correctly, that the operation times meet the plant
requirements and that there are no leakages in the hydraulic connections. If necessary tighten the
nuts of the pipe fittings.
- Check that the required remote signals (valve position, oil pressure, etc.) are correct.
- Check that the setting of the components of the actuator control unit (pressure regulator, pressure
switches, flow control valves, etc.) meet the plant requirements.
- Remove all rust and, in accordance with the applicable painting specifications, repair paint-coat that
has been damaged during transport, storage or assembly.

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Manual 5021, rev. 00 10/2015 – SC/VHS - 15 -
7.2 Stroke adjustment
Important
It is assumed that the following instructions are executed in the workshop
using oil as the power fluid.
Instructions are applicable when the actuator is already installed on the valve.
It is important that the travel stops of the actuator (and not those of the valve) stop the linear stroke at
upper end of valve position, except when this is required by the valve operation.
The setting of the open/closed valve position (upward position) is performed by adjusting the travel stop
screw into the end flange of the hydraulic cylinder and by the adjustment of the coupling of valve stem to
actuator joint for the downward position.
For the adjustment of the travel stop screw in the end flange of the hydraulic cylinder proceed as follows
(Fig.5):
- Loosen the plug (3.4) from the travel stop protection (3.2) keeping the latter locked with a proper
wrench key.
- Adjust the valve stroke screw/unscrew the travel stop screw (3.1)
- After detected the right position, tight the travel stop protection (3.2) against the cylinder end flange
keeping the stopper screw (3.1) locked Screw the plug (3.4) into the travel stop protection (3.2).
Fig. 5 – Stroke adjustment
After stroke adjustment, operate the actuator with hydraulic supply to check that the
actuator moves properly and that there are no leakages.

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Manual 5021, rev. 00 10/2015 – SC/VHS - 16 -
8 MAINTENANCE
8.1 Periodic Inspections
Inspect the general conditions at regular intervals: recommended frequency of inspection is one time
every two years but this frequency could be changed depending on the installation and working
conditions.
- Check that the actuator operates the valve correctly and with the required operating times. If the
actuator operation is very infrequent, carry out a few opening and closing operations with all the
existing controls (remote control, local control, emergency controls, etc.), if this is allowed by the
conditions of the plant.
- Check that the signals to the remote control desk are correct.
- Check that the hydraulic supply pressure value is within the required range.
- If there is an filter on the actuator please check the proper functionality.
- Check that the external components of the actuator are in good conditions.
- Check all the paint-coat of the actuator. If some areas are damaged, repair the paint-coat according to
the applicable specification.
- Check that there is no leak in the hydraulic connections. If necessary tighten the nuts of the pipe-
fittings.
Warning: Take care that a build-up of dust or dirt on the actuator can inhibit cooling
and contribute to increase surface temperature. The user should plan and provide
for a periodic cleaning/maintenance program that will maintain the external surface
of the actuator free from excessive layer of dust.
Important: Use only STI: original spare parts. STI cannot accept responsibility for
any damages that occur from using spare parts or fastening materials from other
manufacturers.
If STI products (i.e. gasket, o-ring etc) have been on store for longer periods check
these for corrosion or deterioration before using these products.

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Manual 5021, rev. 00 10/2015 – SC/VHS - 17 -
8.2 Special maintenance
Under normal condition the actuator don’t need special maintenance. If there are leaks in the hydraulic
cylinder or a malfunction in the mechanical components, or in case of scheduled preventive maintenance,
the actuator must be disassembled and seals must be replaced with reference to the attached sectional
drawing and adopting the following procedures.
Important
Before performing any maintenance operations use always wear protective gloves,
clothing, and eyewear when performing any maintenance operations.
Warning
Before proceeding with any maintenance operation the following instructions must be
respected:
- Disconnect any operating lines providing hydraulic pressure, electric power, or a
control signal to the actuator. Be sure the actuator cannot suddenly open or close
the valve
- Close the hydraulic feed line and make sure that there is no pressure in the
actuator cylinder and the control unit, to ensure safety of maintenance staff.