Flowserve Valtek FlowTop V746 User manual

USER INSTRUCTIONS
Valtek FlowTop
General Service Control Valve
Type V746 and V748
FCD VLENIM8610A4 11/18
Experience in Motion
This document is the Original Instructions’
Installation
Operation
Maintenance

Valtek FlowTop General Service Valve FCD VLENIM8610A4 11/18
2
GeneralServiceControlValve-ValtekFlowTop
The Valtek FlowTop product line is low cost, compact and light-weight. Yet, it is
rugged and can be used safely and confidently in a wide range of general service
applications plant-wide. Its modular design provides trim and material options to
suit most service situations. Simplicity of design reduces maintenance and parts
inventory costs. It is ideally suited for flow and pressure control of liquid and gas
media in oil and gas, power, chemical and petrochemical processing and related
industries. The Valtek FlowTop control valve package provides flow rates, control
accuracy and reliability at levels comparable to special engineered service control
valves, but at a significantly lower cost. The Valtek FlowTop is manufactured to ISO
9001 standards.
The following instructions are designed to assist in unpacking, installing and per-
forming maintenance as required on Flowserve Valtek FlowTop control valves. This
instruction manual does not include specific product design data. Such data can
be found on the valve’s serial plate or specification documents; additionally, dimen-
sional information can be found in the Valtek FlowTop technical bulletin. Procure
needed documents as necessary before you begin any work on the valve.
User Instructions cannot deal with all possible situations and installation options.
It is required that only trained and qualified technicians are authorized to adjust,
repair or work on control valves, actuators, positioners and other accessories.
Review this bulletin prior to installing, operating or performing any maintenance on
the valve. Additional Installation, Operation, and Maintenance Instructions (IOMs)
cover other features (actuators, handwheels, packing and positioners).
To avoid possible injury to personnel or damage to valve parts, WARNING and
NOTICE indicators must be strictly followed. Modifying this product, substituting
non-factory parts or using maintenance procedures other than outlined could
drastically affect performance and be hazardous to personnel and equipment and
may void existing warranties. This manual should be used in conjunction with
applicable local and national laws. Failure to comply with User Instructions will
render the manufacturer’s guarantee and liability null and void. Unless otherwise
agreed, the manufacturer’s general terms and conditions of sale shall apply.
Read the user instructions carefully before use.
Keep for future reference.
Contents
1 Scope of Manual 3 10 Valve Quick-Check 7 - 8
2 Intended Use 3 11 Valve Maintenance 8 - 10
3 Product Identification 3 12 Troubleshooting 10 - 11
4 Valtek FlowTop Modification 3 - 4 13 Disassembly and Reassembly 12 - 19
5 Safety 4 14 Torque Requirements 20
6 Packaging and Transport 4 15 Lubricants 21
7 Storage 4 16 Special Tools 21
8 Unpacking 4 - 5 17 Disposal 21
9 Installation 5 - 7 18 Parts List 22 - 23
Figure 1: Valtek FlowTop with Standard Bonnet
Figure 2: Valtek FlowTop with Bellows Seal

Valtek FlowTop General Service Valve FCD VLENIM8610A4 11/18
3
flowserve.com
1 Scope of Manual
The following user information covers the Valtek FlowTop
general service control valve:
• English ASME Units - Class 150, NPS ½ - 6 - Type V746
• English ASME Units - Class 300, NPS ½ - 6 - Type V748
• Assembled with a pneumatic actuator
• Comes with or without ancillary equipment
2 Intended Use
WARNING
Control valves are pressure ves-
sels designed and rated for spe-
cific application conditions. Before installation, check the
serial number and / or the tag number to ensure that the
valve and actuator being installed are correct for the in-
tended application. Do not use the valve outside of its rated
design limits. Exceeding the design limits may cause haz-
ardous conditions including leakage of the process media
or rupture of the pressure boundary resulting in possible
process loss, equipment or environmental damage, or seri-
ous personal injury or death.
The specific product design data can be found on the valve’s
serial plate, data sheet and the calculation sheet (in acc. to the
IEC 60534-7:2010).
The Valtek FlowTop handles a wide variety of general service
applications, while offering high flow capacity. All sizes come
standard with unbalanced trim; for high pressure drop appli-
cations optional pressure balanced trim is available for NPS
size 3 to 6.
The Valtek FlowTop consists of the body, bonnet, trim,
and actuator. The valve is designed with a high level of in-
terchangeability allowing the user to assemble the greatest
possible number of variations from a minimum number of
components to match each application. There are five bon-
net designs: standard bonnet or extended bonnet (either as
unbalanced or pressure balanced), and bellows seal bonnets.
See Figure 1 and Figure 2.
The Valtek FlowTop is designed in compliance with EN
1349:2009 - Industrial Process Control Valves (DIN EN 1349
and VDE 0409-1349).
The Valtek FlowTop is designed for use in MODERATE and
WORLDWIDE environmental conditions, ambient tempera-
ture range -40°F to 180°F (-40°C to +82°C), air humidity up
to 93% non-condensing, air pollution up to 300 µg/m3, unless
restricted by the accessories.
The product offering may include optional ancillary equip-
ment, such as positioners, air-filter regulators, solenoid
valves, limit switches or boosters. Digital, I/P, or pneumatic
positioners can be mounted directly, with a mounting bracket
or according to NAMUR standards. Refer to the relevant man-
ufacturer‘s user instructions for information regarding other
ancillary equipment.
3 Product Identification
Each Valtek FlowTop (V746 and V748) control valve comes
with an attached serial plate which includes key information
specifically for each control valve:
Figure 3: Serial Plate (WW-design, WorldWide)
R
Made in Villach - Austria
Tag.No.
Kennzeichnung
Fabrikations Nr.
Serial No.
Type
Typ
DN PN/Class
Gehaeuse / Atteste
Body / Certificate
Kegel
Plug Seat
Sitz
Kvs / Cv
Innenteile
Trim
Antrieb
Actuator
S
Betriebstemperatur
Working Temperature
max.
Betriebsdruck
Working Pressure
Characteristic / Stroke
for Actuator
Arrangement
Supply
Sicherheitsstellung
< 30°
Druecke sind Ueberdruecke
Pressures are gauge pressures
Umgebungstemperatur
Ambient Temperature
max.
min.
Kennlinie / Hub
dp
fuer Antrieb
max.
Einbaulage
Besonderheiten
Specialities
Zuluft
Federlaufbereich
Spring Range
Failure Position
min. / max.
Figure 4: Serial Plate (EU-design, European Union)
The same serial number shown on the plate will appear on
all Valtek FlowTop data sheets, dimensional drawings, bills
of material, and spare parts lists. Other information located
on the serial plate is self-explanatory for the Valtek FlowTop
control valve.
You can download .pdf versions of the Valtek FlowTop docu-
mentation including a technical bulletin and user instructions
at www.flowserve.com. It is the user’s responsibility to keep
this and related documentation on file and accessible for the
Valtek FlowTop product.
4 Valtek FlowTop Modification
Valtek FlowTop control valves are generally delivered as tested
and assembled units, with factory-mounted actuators.

Valtek FlowTop General Service Valve FCD VLENIM8610A4 11/18
4
Unauthorized modification of the Valtek Flow-
Top control valve voids the product test certi-
fication and product warranties, could drasti-
cally affect product performance, and could
be hazardous to personnel and equipment.
NOTICE
Before Valtek FlowTop re-use, all necessary
tests must be repeated and recorded in
compliance with all test routines, guidelines and engineering
standards.
5 Safety
Safety terms - WARNING and NOTICE - are used to highlight
specific dangers and / or provide additional information
that may not be readily apparent in the User Instructions.
WARNING directions must be strictly followed.
WARNING
or WARNING indicates that
severe personal injury,
death and substantial property damage can occur if proper
precautions are not taken.
NOTICE
NOTICE indicates practices or provides ad-
ditional technical information.
Green fields indicate safety-related informations.
6 Packaging and Transport
Pay close attention to shipping marks and
transport pictograms.
Careful packing, loading and transport arrangements are
required to prevent products from being damaged during
transport. Standard packaging includes a cardboard box, with
or without a wooden pallet base as needed. Special packaging
may include a wooden box. Packaging may use cardboard,
plastic wrap, foam, or paper as packing material. Filling
material may be a carton type or paper.
Shipping marks display product and package dimensions and
weight (for further information see Packaging and Sending
Instructions, Form L 002). Packing guidelines for export
follow HPE standards. (Nonreturnable packaging may contain
up to 90% recyclable materials.)
7 Storage
Maximum storage time for control valves is
6 months.
NOTICE
The packing box begins to break down after
6 months. Leakage may develop.
Upon arrival on site, store the Valtek FlowTop on a solid base
in a cool, dry closed room. Until its installation, the valve
must be protected from the weather, dirt and other potentially
harmful influences.
Do not remove the protective covers from the body flanges of
the control valve or from the instrument ports of the actuator
and accessories until the valve is ready for installation at the
site.
8 Unpacking
Hoisting and lifting are inherently danger-
ous activities and require safe rigging and
proper training to mitigate hazards. Use
standard industry safety practices, personal
protection, and warranted lifting devises.
WARNING
Crushing hazard ! Arrange rigging
to prevent tipping of the control
valve. Do not allow the valve assembly to rotate during re-
moval. Do not stand under suspended loads. Failure to do
so can cause serious personal injury and damage the valve
or nearby equipment.
NOTICE
Be aware that the center of gravity may be
above the lifting point. Do not allow the sling
to touch the stem, travel indicator or peripheral equipment.
Observe the maximum permitted carrying capacity.
1. Check the packing list against materials received to
ensure all components and accessories are present.

Valtek FlowTop General Service Valve FCD VLENIM8610A4 11/18
5
flowserve.com
2. Place a sling around the actuator case just above the
yoke.
3. You can alternatively hook a
double-leg sling (if necessary
a triple-leg sling) into the lifting
rings mounted on the actuator
(Actuator sizes 500 and 700 cm2,
observe the permissible loading
force).
Figure 5: Triple-leg sling
4. Upon removing the control valve from the packaging,
we recommend that you:
• Promptly touch up any damage to the corrosion pro-
tection.
• Contact your shipper immediately to report any
damage.
• Call your Flowserve representative if you experience
any problems.
• Do not remove the protective covers from the body
flanges of the control valve or from the instrument
ports of the actuator and accessories until the valve
is ready for installation at the site.
Prior to installation of the actuator, we require, that you check the following conditions to reduce the risk of malfunction and
safety related incidents.
No. Check Possible malfunction or safety related incident
1Confirm that the nominal / operational data on the
serial plate matches the operational data of the
facility.
An operational mismatch can cause considerable damage to
the valve or may lead to a failure at the facility.
2Confirm that the line is clear of dirt, welding slag,
chips, scale or other foreign material.
The risk of control valve damage due to foreign particles will be
reduced if a suitable strainer is installed upstream of the valve.
(Suggested mesh size of 0.004 inch (0,1 mm)
3Confirm the piping flanges are coaxial, parallel, and
correspond with the face-to-face dimension of the
valve.
Incompatible sizing may result in excessive tension, valve
malfunction or flange connection leakage.
4Confirm the piping is routed correctly and the valve is
free of additional piping forces.
Incorrect routing may result in leakage and / or potential valve
failure.
5Confirm that the control valve can be installed in an
upright position whenever possible.
Non-upright positioning may increase wear in the packing,
resulting in leakage and premature wear.
9 Installation
The control valve must be installed and com-
missioned by qualified staff - personnel who are
familiar with the installation, commissioning
and operation of this product and possess the
relevant qualifications in their field of activity.
Table 1: Basic safety massages for installing the valve (continued on next page 6)

Valtek FlowTop General Service Valve FCD VLENIM8610A4 11/18
6
No. Check Possible malfunction or safety related incident
6Confirm the actuator has enough overhead clearance
to disassemble the plug from the valve body.
Actuator
Code
Removal Space ≈ R
mm inch mm inch
253
180 7.1
260 10.2
503 290 11.4
701 330 13.0
Table 2: Overhead clearance dimensions
Height of
valve
Face to face
dimensions
≈ R
Removal space
for actuator
Height of
actuator
Figure 6: Overhead clearance drawing
7Confirm there are suitable piping lengths upstream
and downstream of the valve installation site in order
to minimize a sudden pressure surge in the flow.
Absence of suitable piping lengths can create critical operating
conditions and cause unacceptable levels of noise and
vibration.
8Confirm removal of all hazards and ensure appropriate
protective measures are in place.
none
9 Confirm flow direction to ensure the correct valve
installation. Flow direction is indicated by the arrow on
the valve body.
Improper flow direction causes critical changes to operating
conditions that may damage the control valve.
10 Confirm that the air supply and instrument signal
lines are dry and clear of dirt and oil.
At a minimum, the instrument air must conform to ISA- 7.0.01-
1996 (ISO 8573-1 Compressed Air - Class 2) requirement or
those of the accessory manufacturer.
11 Confirm the valve is grounded in order to prevent an
electrical discharge.
Noncompliance may result in electrical discharges.
12 Confirm that the bonnet bolting of valves used in
NACE MR 0175 / MR 0103 or ISO 15 156 applications
are ventilated.
Do not cover or insulate over bonnet flange bolting !
13 Throttling control valves are typically equipped with
a pneumatic actuator and valve positioner. Refer to
the appropriate positioner manual for connections
and maximum air supplies.
The air supply must be limited to less than 87 psig (6 bar)
per the actuator serial plate. An air filter regulator should be
installed to ensure that the supply pressure to the pneumatic
actuator does not exceed the air supply pressure indicated on
the WW or EU serial plate.
Table 1: Basic safety massages for installing the valve
After these requirements are confirmed the valve can be installed and connected in the piping.

Valtek FlowTop General Service Valve FCD VLENIM8610A4 11/18
7
flowserve.com
1. Remove the protective flange covers and coating from
the control valve; clean the flange gasket surface.
NOTICE
Unsuitable cleaning agents can dam-
age and cause leakage in PTFE and
graphite gaskets. Consult a current chemical resis-
tance list before applying.
2. Install the control valve in an upright position whenever
possible. Vertical installation permits easier valve
maintenance.
3. Install and connect the control valve to the pipeline.
Locate gaskets in the center of the body flanges and
secure nuts and bolts.
4. Connect the power supply and instrument signal lines.
10 Valve Quick-Check
Apply appropriate personal protective equip-
ment when working on the control valve to
prevent hazards arising from the operation.
Protect yourself against freezing, burns and
cuts by wearing appropriate protective cloth-
ing, gloves and eye protection.
Do not over-tighten packing.
Sudden exposure of the control valve to
full working pressure and temperature
may cause stress cracks.
Prior to valve operation, we require, that you check the following conditions to reduce the risk of malfunction and safety
related incidents.
No. Important information Possible malfunction or safety related incident
1Avoid critical operating conditions where excessive noise
or vibration levels might occur.
Impermissible continuous operation of a control valves
under critical conditions can damage the valve.
2Avoid frequent system start-ups and shutdowns. Critical operating conditions, which can damage the
control valve, may be encountered during system start-up
or shut down.
3Keep the operating medium free of foreign particles. Installing a suitable strainer upstream of the control valve
can prevent foreign particles from damaging the valve.
4
Instrument air must conform to ISA 7.0.01-1996 (with a dew
point at least 18°F (10°C) below ambient temperature, par-
ticle size below 1 µm and oil content not to exceed 1 ppm)
Contaminated instrument air can damage the accessories
and control valve or cause them to fail.
5Do not touch the body and bonnet ! The tempera-
ture of the operating medium is transferred to
the surface of the linear actuator.
Excessive hot surface temperatures can put you at risk for
burns.
Frigid surface temperatures can put you at risk for
freezing.
6Critical operating conditions can cause exces-
sive or hazardous levels of vibration or noise.
Impermissible levels of vibration can cause hearing
loss, vascular and nerve damage and damage to joints
and bones. Use hearing protection when noise levels
exceed 80 dB(A).
7
Incorrect maintenance can result in the emission
of hot, cryogenic, and / or toxic operating media.
Incorrect maintenance can put you at risk for heat
related burns, freezing, acid burns or poisoning.
Table 3: Basic safety massages for operating the valve

Valtek FlowTop General Service Valve FCD VLENIM8610A4 11/18
8
4. Continuously increase load until operation parameters
are reached.
5. Minor relaxation of the flange bolting is possible after
initial assembly. Retorque the bonnet flange bolting
if necessary before installation or following an initial
temperature excursion to ensure the bonnet gaskets
do not leak (See Table 4).
Pressure Class 150 1) Class 300 1)
Size Nm ft lb Nm ft lb
1/2“
15 11 15 113/4“
1“
1 1/2“ 23 17 24 18
2“ 28 21 32 24
3“ 24 18 37 27
4“ 41 30 71 52
6“ 72 53 146 108
1) V746 is designed for Class 150 while V748 is desigend for Class 300
Table 4: Recommended Body Bolt Torque Values
Recommended Maintenance Actions
No. Service
Inter-
val
Valve Condition
Good Adequate Inadequate
1Visual inspection of
the valve
Bi-
weekly
No action Clean valve stem with a soft
cloth
Overhaul or replace valve after product
lifecycle
2Visual inspection of
the packing
Bi-
weekly
No action Retighten leaky packing box Replace leaky packing box immedi-
ately
Preventive change of
the PTFE-packing
Dependent upon results of previous maintenance (see numbers 1 and 2 above) or a
minimum of once every 24 months
3 Visual inspection of
body bolting
Yearly No action Retighten body bolting if
bonnet gasket leaks.
Remove from service and replace body
bolting immediately if gasket leakage
persists or if bolting is damaged
4Visual inspection of
the actuator
Bi-
weekly
No action Clean actuator stem with a
soft cloth
Overhaul or replace actuator after prod-
uct lifecycle
5 Preventive overhaul of
the valve
Dependent upon results of previous maintenance (see numbers 1 to 4 above) or a
minimum once every 60 months
6Operation test No action Perform 3 full strokes if packing and / or bonnet tightening is
modified; check for leakage
11 Valve Maintenance
Maintenance intervals and service life of a valve can only be
determined empirically on site. The intervals specified in the
User Instructions are recommendations and serve only as a
guide. Under problematic operating conditions, maintenance
intervals may be significantly reduced. We strongly recom-
mend a site survey followed by establishing a documented
procedure for performing the maintenance work. Maintenance
personnel should perform and log the work accordingly. The
data collected can be used as a basis for dynamically deter-
mining the maintenance intervals and activities.
WARNING
Due to risk of crushing hazard, do
not work between the yoke legs
while the valve is in operation.
Prior to start-up, we strongly recommend that you:
1. Stroke the valve and compare the plug position
indicator on the stem clamp to the stroke indicator
plate. The plug should change position in a smooth,
linear fashion.
NOTICE
If over tightened, excessive friction
may impair smooth control.
2. Adjust instrument signals to ensure a full stroke.
3. Check the packing box bolting to ensure the correct
adjustment (See Section 11: Valve Maintenance).
NOTICE
Over tightening can cause excessive
packing wear and high stem friction
that may impede plug movement.

Valtek FlowTop General Service Valve FCD VLENIM8610A4 11/18
9
flowserve.com
Recommended maintenance actions using the Logix digital positioner with ValveSight diagnostic solution software
No. Service
Inter-
val
Valve Condition
Good Adequate Inadequate
7Visual inspection of
diagnostic interface
Weekly No action -
valve is healthy
Take action per warning Overhaul or replace required part per
alarm
8Check health parameter
of valve
Warn-
ing
No action -
valve is healthy
Replace packing box compo-
nents per warning
Overhaul or replace valve after alarm
9Check health parameter
of actuator
Warn-
ing
No action -
actuator is
healthy
Check and retighten air
supply
Overhaul or replace actuator after
alarm
10 Check health parameter
of control
Warn-
ing
No action -
control is
healthy
Overhaul or replace valve; trim and bonnet components must be
checked and / or repaired after alarm
11 Check health parameter
of positioner
Warn-
ing
No action -
positioner is
healthy
Start step test Overhaul or replace positioner after
alarm
Table 5: Service activities check list
Prior to valve operation, we require, that you check the following conditions to reduce the risk of malfunction and safety
related incidents.
No. Check Possible malfunction or safety related incident
1 Check the packing follower for proper tightness. The packing follower is spring loaded and factory adjusted.
If leakage is detected around the packing follower tighten it
clockwise using a wrench in quarter turn intervals until the
leakage stops.
Wrench Size Adjustment Interval Maximum Adjustment
SW 24 ~ 15/16 AF
quarter turn
one,
three-quarter turn
SW 32 ~ 11/4AF
SW 46 ~ 113/16 AF one complete turn
Table 7: Packing Adjustment
Do not overtighten packing.
Overtightened packing can cause excessive packing wear and
high stem friction that may impede plug movement.
If leakage cannot be stopped, the packing must be replaced.
2Check for signs of gasket leakage through the bonnet
and end flanges.
Tighten the bonnet bolting nuts. See Section 13: Disassembly
and Reassembly for instructions. Also see Table 4 in Section 10.
3 Check if all nuts and bolts are securely fastened. Avoid critical operating conditions if excess noise or
vibration levels occur during operation.
4Check valve for smooth, full-stroke operation. Un-
steady stem movement could indicate an internal
valve problem.
Internal valve failure requires an immediate overhaul or control
valve replacement by qualified stuff.
Table 6: Basic safety massages for maintenance the valve

Valtek FlowTop General Service Valve FCD VLENIM8610A4 11/18
10
After these requirements are confirmed proceed with valve
maintenance.
WARNING
Crushing hazard ! Failure to keep
hands, hair, and clothing away
from all moving parts when operating the control valve can
cause serious injury.
1. Clear all dirt and / or foreign material from the plug
stem and control valve.
2. If leakage is detected, retighten the packing follower by
one full turn clockwise (See Table 7: Packing Adjust-
ment).
3. If retightening packing does not stop the leakage,
overhaul the control valve and replace the packing
(See Section 13: Disassembly and Reassembly).
4. If leakage is detected, retighten bonnet and flange
bolting.
5. Make sure all nuts and bolts are securely fastened.
6. If possible, stroke the valve and check for smooth,
full-stroke operation. Unsteady stem movement could
indicate an internal valve problem.
7. Make sure all accessory brackets and bolting are
securely fastened.
8. Check control valve health parameters:
• Characteristic curves of the valve with flow
• Upstream pressure
• Downstream pressure
into the control room.
NOTICE
Monitor trim and bonnet compo-
nents. If nominal and actual values
differ by more than 5%, maintenance may be required.
12 Troubleshooting
Contact customer service department or contract partner for any fault or defect found, otherwise
the manufacturer‘s guarantee shall be rendered null and void and the manufacturer released from
any responsibility. If the user performs the repairs, these User Instructions must be adhered to and
carried out in a competent manner. Original Equipment Manufacturer spare parts must be used to
make the repair.
Defect No. Possible Causes Remedy
Stem does not move 1.1 • No auxiliary energy
supply (pneumatic air) to
actuator and accessories
(positioner, air filter regulator,
solenoid valve, limit switch, and/
or special accessories)
• Pneumatic actuators:
Check supply for leaks
Check air pressure (usually 87 psig; 6 bar)
1.2 • Mounted accessories do not work • See User Instructions for accessory manufacturer
1.3 • Pneumatic actuator is defective • Contact customer service department or contract
partner
1.4 • Excessive tightening of the pack-
ing box
• Loosen packing follower until valve operates
properly
NOTICE
Make sure there are no leaks.
1.5 • Valve trim worn or stuck • Contact customer service department or contract
partner
Jerky stem movement 2.1 • Damaged stem • Contact customer service department or contract
partner

Valtek FlowTop General Service Valve FCD VLENIM8610A4 11/18
11
flowserve.com
Defect No. Possible Causes Remedy
Jerky stem movement 2.2 • Actuator not powerful enough • Compare actuator specifications on the serial
plate with operation specifications of the facility. If
incompatible, contact customer service department
or contract partner
Stem travel less than full stroke
(0 to 100 %)
3.1 • Air supply pressure too low • Provide air at the pressure stated on the serial plate
(European production only).
3.2 • Pneumatic actuators:
Improper handwheel position
• Move handwheel to limit position , otherwise
contact factory for information.
3.3 • Improperly adjusted or defective
positioner
• Readjust positioner to positioner manufacturer‘s
specification
3.4 • Foreign particles in valve seat or
damaged trim
• Contact customer service department or contract
partner
Excessive valve seat leakage 4.1 • Damaged sealing surfaces on
valve seat or plug
• Contact customer service department or contract
partner
4.2 • Foreign particles in seat area • Contact customer service department or contract
partner
4.3 • Plug does not close fully • Refer to No. 3.1 to 3.5
Leaking packing box system 5.1 • Compression force on packing box
too low
• Slightly retighten packing box
NOTICE
Make sure stem can still move.
5.2 • Worn packing • Slightly retighten packing box
NOTICE
Make sure stem can still move.
If the packing does not stop leaking, contact
customer service department or contract partner
5.3 • Dirty stem • Clean stem with suitable cleaning agent
5.4 • Damaged stem • Contact customer service department or contract
partner
Leaking bonnet gasket 6.1 • Gasket compression is too low • Properly retighten bonnet bolting nuts crosswise
6.2 • Gasket defective • Contact customer service department or contract
partner
6.3 • Corrosion • Contact customer service department or contract
partner
Leaking body 7.1 • Corrosion or high velocity related
damage
• Contact customer service department or contract
partner
No limit switch signal 8.1 • Power supply to limit switch
interrupted
• Check power supply
(connections, circuit breakers, voltage)
8.2 • Limit switch out of adjustment • Readjust limit switch operating distance; see limit
switch data sheet
Unstable positioner 9.1 • Defective positioner • See user instruction of the positioner manufacturer
Table 8: Trouble-shooting

Valtek FlowTop General Service Valve FCD VLENIM8610A4 11/18
12
13 Disassembly and Reassembly
The Valtek FlowTop control valve is al-
lowed to be disassembled and reassem-
bled only by qualified staff - personnel
who are familiar with disassembling, re-
assembling, installation and commission-
ing of this product, and possess the rele-
vant qualifications in their field of activity.
When performing repairs, personnel are to follow these
instructions using only original equipment manufacturer
(OEM) spare parts and recommended special tools to ensure
the reliability of the Valtek FlowTop control valve.
Only Flowserve trained and authorized personnel are allowed
to repair (disassemble and reassemble) the Valtek FlowTop in
hazard areas.
Valves are provided for oil and grease-less service or oxygen
service may only disassembled and reassembled in clean
rooms (ISO 14644- ISO 8, US FED STD 209 E - M 6.5, or
equivalent).
Prior to installation of the actuator, we require, that you check the following conditions to reduce the risk of malfunction and
safety related incidents.
No. Important information Possible malfunction or safety related incident
1Disregarding these instructions may bring serious or
harmful consequences.
Failure to comply with these user instructions will render
the manufacturer‘s guarantee and liability null and void.
Unless otherwise agreed, the manufacturer‘s general
terms and conditions of sale shall apply.
2
Always observe system safety instructions when
preparing for and performing the repair procedure.
Potential hazards and their sources are under the operator‘s
influence. The operator must observe national and interna-
tional environmental regulations for control valve removal
from the pipe and cleaning. Permissible exposure limits
must be maintained, appropriate personal protective equip-
ment must be used and service personnel must be properly
instructed in performing the repair procedure.
3Make sure the pipeline is depressurized an in
ambient state, also a suitable rigging (e.g. End-
less Sling) and securing devices (e.g. Vee Trough with
Stands / Vise) are readily available.
Remove the Valtek FlowTop from the pipeline in a depres-
surized and ambient state. Failure to do so can cause seri-
ous personal injury.
The control valve is not equipped with integral stands,
therefore guard against the valve from tipping over. Bodily
injuries can be the result. Use appropriate clamps, block-
ing or other stabilizing support. Attachment to overhead
crane can ensure stability.
4Confirm that you have the required spare parts at the site. Not having the full complement of parts, accessories and
tools can slow or stop repair work.
5Confirm that you have the required tools avail-
able to manage the disassembly and reassem-
bly (See Section 16: Special Tools).
Improper tools and / or improper use of tools can result
in personal injury or damage to the parts.
6Review the serial plate information to identify the valve.
The serial number and the part numbers needed are re-
quired when ordering spare parts.
A serial plate used for product identification is attached
on every control valve (See Section 3: Product Identifica-
tion).
7 Do not damage any valve surfaces during repair. Damaging the stem surface and / or packing area may
lead to premature leakages in the packing area.
8Check all parts for damage such as scoring, deformities,
corrosion or overexpansion.
If in doubt, replace faulty parts.
Never reuse gaskets.
Table 9: Basic safety massages for repairing the control valve
WARNING
Control valves are pressure vessels.
Improper opening of the valve or actuator can result in bodily injury.

Valtek FlowTop General Service Valve FCD VLENIM8610A4 11/18
13
flowserve.com
After these requirements are confirmed the control valve can be maintained and repaired.
Description of the Procedure
1. Disconnect the air supply from the actuator and / or
assembled accessories.
2. Disassemble the positioner from the valve as neces-
sary (See Figure 7: Remove the positioner).
3. Move the actuator to the open (retracted) position.
4. Turn the cap screws (240) counter clockwise to loosen
(See Figure 8: Remove the actuator).
5. Turn the lock nut (113) clockwise to loosen. Keep ac-
tuator coupling (345) from turning by securing with a
wrench.
6. Turn the yoke lock nut (76) counter clockwise to loos-
en.
7. Lift off and store the actuator safely.
8. Place the valve body assembly on a table for disas-
sembly.
Disassembly instructions of the valve body
assembly.
1. Turn the lock nut (113) counter clockwise to loosen.
2. Turn the packing follower (80) counter clockwise to
loosen.
3. Remove the Belleville springs (138) (Option, see Parts
List - Packing Details).
4. Remove the upper stem guide (87).
5. Turn the bonnet nuts (114) counter clockwise to loosen.
6. Place the Ring Nut Tool (See Section 16: Special Tools)
on the stem (51) then slowly turn the bonnet assembly
(40).
WARNING
Crushing hazard ! Lifting
the bonnet and plug from
the control valve involves personal physical risk by
falling parts.
Please exercise caution.
Positioner
O-ring
Socket screw
Figure 7: Remove the positioner
345
240
76
249
113
Figure 8: Remove the actuator
Item Part Item Part
76 Yoke Lock Nut 249 Actuator Coupling
113 Lock Nut 345 Valve Coupling
240 Socket Head Srew (2x)
Table 10: Coupling parts identification

Valtek FlowTop General Service Valve FCD VLENIM8610A4 11/18
14
NOTICE
Exercise care with a pressure bal-
anced plug design. While removing
the pressure balanced plug, the retainer may stick to
the bonnet then become detached while lifting the plug
and stem out of the valve. Secure the seat retainer as
you remove the plug and stem.
7. Remove the bonnet gasket (58) and seat retainer gas-
ket (56).
8. Remove the seat retainer (30), seat ring (20) and pro-
file ring (55).
9. Remove the plug assembly (50) from the bonnet (40).
10. Use the Packing Driver Tool (See Section 16: Special
Tools) to remove the packing box ring (93), packing
(88) and the upper guiding (87) (Details see Parts List
- Packing Details ).
11. Use a standard brass scraper or other suitable tool to
remove all old gasket material; then clean the gasket
surfaces.
NOTICE
Examine the valve trim and bonnet
components. If the nominal and ac-
tual values differ by more than 5% a control valve
overhaul may be required (See Point 8, Page 9).
12. Check stressed surface areas for damage such as
scoring and deformities.
13. Use a standard brass scraper or other suitable tool to
clean bolting. Check for corrosion or any other damage.
Reassembly instructions of the valve body
assembly.
14. Lubricate all bolt and screw threads and bearing sur-
faces (stem, underside of the nuts) with a suitable, ap-
proved lubricant (See Section 15: Lubricants).
NOTICE
Never allow lubricants to come in contact
with the bonnet or sealing surfaces.
15. Install a new profile ring (55) and seat ring (20).
16. Lower the seat retainer (30) into the body and place it
on top of the seat ring (See Figure 9).
17. Lower the plug assembly (50) into the body with the
plug touching the seat ring surface.
80
138
87
88
93
114
40
58
51
52
50
56
30
20
55
108
1
Figure 9: Disassemble / Reassemble the valve
Item Part Item Part
1 Body 58 Bonnet gasket
20 Seat ring 65 O-ring (Figure 10)
30 Seat retainer 66 Backup ring (Figure 10)
Sleeve (Figure 10) 80 Packing follower
40 Bonnet 87 Upper guiding
50 Plug 88 Packing
51 Stem 93 Packing box ring
52 Lock bushing 108 Stud bolt
55 Profile ring 114 Hex nut
56 Seat retainer gasket 138 Belleville spring
Table 11: Valve parts

Valtek FlowTop General Service Valve FCD VLENIM8610A4 11/18
15
flowserve.com
18. Install the new seat retainer gasket (56) and the new
bonnet gasket (58).
19. Carefully lower the bonnet (40) onto the plug in the
body of the valve (See right column for pressure bal-
anced trim).
20. Install and finger tighten the bonnet nuts (114) to the
bonnet bolts (108).
21. Install the packing box ring (93) and the new packing
(88).
NOTICE
Install and push two packing rings
consecutively using the Tamping
Tool and pre-tighten it. Repeat the procedure with re-
maining rings. Rotate each ring 180° from the overlap-
ping point. Make sure each ring is clean. Dirty rings
result in stem leakage.
There are different versions - for details see Parts
List - Packing Details (see Page 19).
22. Install the upper guide (87), Belleville springs (138)
and the packing follower (80). Tighten the packing fol-
lower with your fingers clockwise until resistance can
be felt.
NOTICE
The belleville springs (138) must be
stacked in series.
23. Tighten the bonnet nuts (114) in four steps - 30%,
60%, 100%, and all around 100% - using a crosswise
pattern (See Section 14: Torque Requirements).
NOTICE
Check the plug’s freedom of movement
by lifting it approximately ~10 mm (0.4
inch) between tightenings. Loosen the bolted connection
and start again if it proves difficult to move the plug.
24. Finish packing follower (80) tightening with a wrench
(See Table 7, Page 9).
25. Replace the pneumatic diaphragm actuator and acces-
sories (See page 13).
26. After reinstalling the control valve in the pipeline,
perform 3 full strokes and check the tightening of the
packing follower and bonnet bolting.
NOTICE
Do not over tighten the packing. Over
tightened packing may produce
higher friction and reduce product service life.
27. Log the maintenance interval and the work performed.
Bonnet version with a pressure balanced trim:
28. Lubricate all bolt and screw threads and bearing sur-
faces (stem, underside of the nuts) with a suitable,
approved lubricant (See Section 15: Lubricants).
NOTICE
Never allow lubricants to come in contact
with the bonnet or sealing surfaces.
29. Reassemble the pressure balanced plug with new backup
rings (66) and a new O-ring (65) (See Figure 10).
30. Install a new profile ring (55) and seat ring (20).
31. Lower the sleeve (30) into the body and place it on top
of the seat ring (20).
32. Lower the pre-assembled plug assembly (50) into the
sleeve (30) with the plug head touching the seat ring.
33. Install the new seat retainer gasket (56) and the new
bonnet gasket (58).
34. Lower the bonnet (40) onto the stem (51) of the plug
assembly (50) in the body of the valve.
35. Continue with the standard procedure in the chapter 20.
51
66
65
66
52
56
50
30
Figure 10: Pressure balanced design
Disassembly of the valve with a Bellows Seal
Bonnet Assembly.
1. Turn the bonnet nuts (114) counter clockwise to loosen
(See Figure 11: Disassemble / Reassemble the valve
with bellows seal bonnet type A).
2. Turn the packing follower (80) counter clockwise to
loosen.
3. Remove the Belleville springs (138).

Valtek FlowTop General Service Valve FCD VLENIM8610A4 11/18
16
4. Remove the upper stem guide (87).
5. Place the Ring Nut Tool clockwise (See Section 16:
Special Tools) on the stem (51) and turn slowly.
WARNING
Crushing hazard ! Lifting
the bonnet and plug from
the control valve involves personal physical risk by
falling parts.
Please exercise caution.
6. Remove the bonnet gasket (58) and seat retainer gas-
ket (56).
7. Remove the seat retainer (30), seat ring (20) and pro-
file ring (55).
8. Turn the bonnet nuts (110) counter clockwise to loosen.
9. Remove the head (40) and upper bonnet gasket (59).
NOTICE
There are two different bellows seal
designs.
Type Size
Twist lock between
plug and stem
Connection between
bellows and bonnet
A 15 - 50 1/2“ - 2“ Lock bushing Clamped
B 65 - 150 3“ - 6“ Lock pushing Screwed
Table 12: Bellows seal bonnet types
10. Disassembling each type of Bellows Seal Assembly:
Type A Bellows Seal Assembly:
Lower the plug (50) into a three jaw-chuck with soft
brackets and turn the plug from the stem and bonnet
(51 / 5) counter clockwise to loosen then move the
bellows seal assembly up and out.
Type B Bellows Seal Assembly:
Turn the hex nut (104) from the bellows seal assembly
(51) counter clockwise to loosen, remove the seal car-
rier (91) and profile ring (60) then move the bellows
seal assembly down and out.
NOTICE
The bolting between plug and stem
are secured against twisting. Type A
and B bellows seal assemblies are secured with a lock
bushing (52). The lock bushing (52) usually remains in
the plug (50) and can be reused. If the plug (50) is
damaged and replaced, a new lock bushing (52) must
be used.
11. Use the Packing Driver Tool (See Section 16: Special Tools)
80
138
88
87
93
48
42
40
110
59
51
59
106
5 114
52
50
58 56
30
20
55
108
1
Figure 11: Disassemble / Reassemble the valve with bellows seal assembly
for type A designs (Valve parts see Table 13, Page 17)

Valtek FlowTop General Service Valve FCD VLENIM8610A4 11/18
17
flowserve.com
to remove the packing (88) and the packing box ring (93).
12. Use a standard brass scraper or other suitable tool to
remove all old gasket material; then clean the gasket
surfaces.
NOTICE
Examine the valve trim and bonnet
components. If the nominal and ac-
tual values differ by more than 5% a control valve
overhaul may be required.
13. Check stressed surface areas for damage such as
scoring or deformities.
14. Use a standard brass scraper or other suitable tool
to clean all bolting. Check for corrosion or any other
damage.
Reassembly of the valve with a Bellows Seal
Bonnet Assembly:
15. Lubricate all bolt and screw threads and bearing sur-
faces (stem, plug, underside of the nuts) with a suit-
able, approved lubricant (See Section 15: Lubricants).
NOTICE
Never allow lubricants to come in
contact with the bonnet or sealing
surfaces.
16. Lower the plug (50) into a three jaw-chuck with soft
brackets and install a new lock bushing (52) into the
plug (Type A and B).
NOTICE
The cone of the lock bushing must
open to the top.
Reassembling Type A bellows:
Carefully lower the bonnet (5) onto the plug. Install a
new head gasket (59) and insert the bellows seal as-
sembly (6) from the top of the bonnet (5). Finger tight-
en the stem (51) clockwise onto the plug (50). Tighten
the stem (51) using a suitable torque wrench.
Reassembling Type B bellows:
Install the bellows seal assembly (51) clockwise onto
the plug (50). Tighten the stem (51) using a suitable
torque wrench.
Insert the bellows seal assembly (51) type B through
the underside of the bonnet (5), install a new profile
ring (60) and seal carrier (91) on top. Turn hex nut
104
91
60
106
5
52
51
50
Figure 12: Disassemble / Reassemble the valve with bellows seal assembly for
type B design
Item Part Item Part Item Part
1 Body 52 Lock bushing 91 Seal carrier
5 Bonnet 55 Profile ring 93 Packing box ring
20 Seat ring 56 Seat ret. gasket 104 Hex nut
30 Seat retainer 58 Bonnet gasket 106 Stud bolt
40 Head 59 Head gasket 108 Stud bolt
42 Plug screw 60 Profile ring 110 Hex nut
48 Plug gasket 80 Packing follower 114 Hex nut
50 Plug 87 Upper stem guide 138 Belleville spring
51 Stem 88 Packing
Table 13: Valve parts with bellows seal

Valtek FlowTop General Service Valve FCD VLENIM8610A4 11/18
18
29. Finish packing follower tightening with a wrench (See
Table 7, Page 9).
30. Replace the pneumatic diaphragm or multi-turn actua-
tor and accessories (See page 19).
31. After reinstalling the control valve in the pipeline,
perform 3 full strokes and check the tightening of the
packing follower and bonnet bolting.
NOTICE
Do not over tighten the packing. Over
tightened packing may produce
higher friction and reduce product service life.
32. Log the maintenance interval and the work performed.
MegaStream noise reduction and CavStream
anti-cavitation trims:
Structurally, there is no difference between a seat retainer
and a MegaStream retainer; both are assembled and disas-
sembled identically. Follow instructions in Section 13.
Figure 13: MegaStream
CavStream should be treated the same as the plug assembly.
Follow same instructions as noted on pages 13 through 18.
Figure 14: CavStream
NOTICE
Care should be taken to observe any
wear on the CavStream plug head.
(104) clockwise and finger tighten.
(See Section 14: Required Torques, for plug and stem)
17. Install the new bonnet gasket (58).
18. Install a new profile ring (55) and seat ring (20).
19. Lower the seat retainer (30) into the body and place it
on the seat ring.
20. Install the new seat retainer gasket (56) and the new
bonnet gasket (58).
21. Lower the plug assembly (50) into the body and place
it into the seat ring.
22. Install and finger tighten the bonnet nuts (114) to the
bonnet bolts (108).
23. Install the new head gasket (58) and carefully lower
the head (40) onto the stem and bonnet.
24. Install and finger tighten the nuts (110) to the studs (106).
25. Install the packing box ring (93) and the new packing (88).
NOTICE
Install and push two packing rings
consecutively using the Tamping
Tool and pre-tighten it using the Compression Tool.
Repeat the procedure with remaining rings. Rotate
each ring 180° from the overlapping point. Make sure
each ring is clean. Dirty rings result in stem leakage.
(See Parts - Packing, Page 20)
26. Install the upper stem guide (87), Belleville springs
(138), and the packing follower (80). Tighten the
packing follower with your fingers clockwise until
resistance can be felt.
NOTICE
The Belleville springs (138) must be
stacked in series.
27. Tighten the bonnet nuts (114) in four steps - 30%,
60%, 100%, and all around 100% - using a crosswise
pattern (See Section 14: Torque Requirements).
28. Tighten the nuts (110) in four steps - 30%, 60%, 100%,
and all around 100% - using a crosswise pattern (See
Section 14: Torque Requirements).
NOTICE
Check the plug’s freedom of move-
ment by pushing / lifting it approxi-
mately ~ 10 mm (0.4 inch) between tightenings. Loosen
the bolted connection and start again if it proves difficult
to move the plug.

Valtek FlowTop General Service Valve FCD VLENIM8610A4 11/18
19
flowserve.com
Reassemble the actuator and positioner
onto the valve:
1. Mount the pneumatic diaphragm actuator onto the
bonnet and tighten the yoke lock nut (76) clockwise
(see Section 14: Required Torques).
NOTICE
Position the actuator with the vent
plug positioned at the rear.
2. Move the actuator to the open position.
3. Screw in the lock nut (113) and actuator coupling (345)
and adjust the distance between the valve coupling
(345) and actuator coupling (249) by adjusting the
stroke length.
Size Stroke
1/2“ - 2“ 20 + 0,5 mm 0.787 + 0.02 in.
3“ - 4“ 40 + 0,5 mm 1.574 + 0.02 in.
6“ 60 + 0,8 mm 2.362 + 0.03 in.
Table 14: Stroke adjustment length
4. Adjust the valve coupling (345) until the actuator
coupling (249) lines up.
NOTICE
Press the stem / plug into the seat by
hand.
5. Move the actuator to the close position and install the
cap screws (240).
6. Secure the lock nut (113). Keep actuator coupling
(249) from turning by securing with a wrench.
7. Reassemble the positioner on the valve as necessary
(see relevant accessory User Instruction).
8. Connect the valve into the pipeline (See Section 9:
Installation).
9. After reinstalling the control valve into the pipeline,
perform three full strokes and check the tightness of
the packing follower and bonnet bolting (See Section
10: Valve Quick-Check).
10. Log the maintenance interval and the work performed.
345
240
76
249
113
Figure 15: Reassemble the actuator
Item Part Item Part
76 Actuator Lock Nut 249 Actuator Coupling
113 Lock Nut 345 Valve Coupling
240 Socket Head Screw (2x)
Table 15: Coupling parts identification
Positioner
O-ring
Socket screw
Figure 16: Reassemble the positioner

Valtek FlowTop General Service Valve FCD VLENIM8610A4 11/18
20
Parts - Packing
Type Detail
PTFE - rings Graphite - rings
Detail Standard Spring loaded Standard Spring loaded
Packing Assembly
The two Belleville springs must be stacked in series !
14 Torque Requirements
Presssure
Class
Torque Requirements for BONNET NUTs (1.4) per nominal diameter
1/2“ 3/4“ 1“ 1 1/2“ 2“ 3“ 4“ 6“
Class 150 1)
Nm 15 23 28 24 41 72
Class 300 1) 24 32 37 71 146
Class 150 1)
ft lb 11 17 21 18 30 53
Class 300 1) 18 24 27 52 108
1) V746 is designed for Class 150 while V748 is desigend for Class 300
Presssure
Class
Torque Requirements for HEAD NUTs (110) per nominal diameter
1/2“ 3/4“ 1“ 1 1/2“ 2“ 3“ 4“ 6“
Class 150 Nm 13 14 30 24
Class 300 10 12 25 46
Class 150 ft lb 9.6 10.3 22 17.7
Class 300 7.4 8.9 18.4 34
Presssure
Class
Torque Requirements for PLUG and STEM (50, 6) per nominal diameter
1/2“ 3/4“ 1“ 1 1/2“ 2“ 3“ 4“ 6“
Class 150 / 300 Nm 40 80 170
Class 150 / 300 ft lb 30 59 125
NOTICE
The yoke lock nut (76) should be tighten with a rounded chisel and a 1,5 kg (3.5 lbs) hammer before the
‘kickback’ effect occurs. The coupling part bolting should be tighten properly by hand in accordance with the
relevant technical standards.