KSB 4STC Installation instructions

KSB Mechanical Seal
4STC
For the Amarex KRT, Sewatec and Amacan Type Series
Installation/Operating Manual

Legal information/Copyright
Installation/Operating Manual 4STC
Original operating manual
All rights reserved. The contents provided herein must neither be distributed, copied, reproduced,
edited or processed for any other purpose, nor otherwise transmitted, published or made available to a
third party without the manufacturer's express written consent.
Subject to technical modification without prior notice.
© KSB SE & Co. KGaA, Frankenthal 11/03/2022

Contents
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Contents
1 General.................................................................................................................................................... 4
1.1 Principles ...........................................................................................................................................................4
1.2 Target group.....................................................................................................................................................4
1.3 Other applicable documents............................................................................................................................4
1.4 Symbols .............................................................................................................................................................4
1.5 Key to safety symbols/markings.......................................................................................................................5
2 Safety...................................................................................................................................................... 6
2.1 General..............................................................................................................................................................6
2.2 Intended use .....................................................................................................................................................6
2.3 Personnel qualification and training...............................................................................................................6
2.4 Consequences and risks caused by non-compliance with this manual .........................................................6
2.5 Safety awareness ..............................................................................................................................................7
2.6 Safety information for the user/operator.......................................................................................................7
2.7 Safety information for maintenance, inspection and installation ................................................................7
2.8 Unauthorised modes of operation..................................................................................................................7
3 Transport/Storage/Disposal .................................................................................................................. 8
3.1 Checking the condition upon delivery............................................................................................................8
3.2 Transport...........................................................................................................................................................8
3.3 Storage/preservation........................................................................................................................................8
3.4 Return to supplier.............................................................................................................................................9
3.5 Disposal ...........................................................................................................................................................10
4 Description............................................................................................................................................ 11
4.1 General description ........................................................................................................................................11
4.2 Product information as per Regulation No. 1907/2006(REACH).................................................................11
4.3 Designation.....................................................................................................................................................11
4.4 Materials .........................................................................................................................................................11
4.5 Design details..................................................................................................................................................11
4.6 Configuration and function...........................................................................................................................12
5 Installation/Dismantling...................................................................................................................... 13
5.1 Permissible aids...............................................................................................................................................13
5.2 Prerequisites....................................................................................................................................................13
5.3 Installing the mechanical seal........................................................................................................................14
5.4 Removing the mechanical seal ......................................................................................................................15
5.5 Tightening torques.........................................................................................................................................15
6 Operation.............................................................................................................................................. 16
6.1 Safety instructions for operation...................................................................................................................16
6.2 Emissions .........................................................................................................................................................16
6.3 Operating limits..............................................................................................................................................17
7 Maintenance......................................................................................................................................... 18
7.1 Maintenance/inspection.................................................................................................................................18
8 Trouble-shooting.................................................................................................................................. 19
9 Related Documents.............................................................................................................................. 20
9.1 General drawings with list of components...................................................................................................20
9.1.1 Variant with axially secured primary ring carrier ............................................................................20
9.1.2 Variant without axially secured primary ring carrier.......................................................................21
9.1.3 Variant with clamped mating ring carrier........................................................................................22
10 Certificate of Decontamination........................................................................................................... 23
Index ..................................................................................................................................................... 24

1 General
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1 General
1.1 Principles
This operating manual is valid for the type series and variants indicated on the front
cover.
The operating manual describes the proper and safe use of this equipment in all
phases of operation.
The order number and order item number of the pump clearly identify the
mechanical seal via the corresponding material number in the pump's parts list and
serve as identification for all further business processes.
In the event of damage, immediately contact your nearest KSB service facility to
maintain the right to claim under warranty.
For any queries contact [email protected]
1.2 Target group
This operating manual is aimed at the target group of trained and qualified specialist
technical personnel.
1.3 Other applicable documents
Table1: Overview of other applicable documents
Document Contents
Data sheet Description of the technical data of the pump (set)
in which the mechanical seal is installed.
General assembly drawing1) Description of the mechanical seal as part of the
sectional drawing of the pump
Sub-supplier product literature1) Operating manuals and other product literature
describing accessories and integrated machinery
components
For accessories and/or integrated machinery components, observe the relevant
manufacturer's product literature.
1.4 Symbols
Table2: Symbols used in this manual
Symbol Description
✓Conditions which need to be fulfilled before proceeding with the
step-by-step instructions
⊳Safety instructions
⇨Result of an action
⇨Cross-references
1.
2.
Step-by-step instructions
Note
Recommendations and important information on how to handle
the product
1If agreed to be included in the scope of supply

1 General
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1.5 Key to safety symbols/markings
Table3: Definition of safety symbols/markings
Symbol Description
!DANGER
DANGER
This signal word indicates a high-risk hazard which, if not avoided,
will result in death or serious injury.
!WARNING
WARNING
This signal word indicates a medium-risk hazard which, if not
avoided, could result in death or serious injury.
CAUTION
CAUTION
This signal word indicates a hazard which, if not avoided, could
result in damage to the machine and its functions.
Explosion protection
This symbol identifies information about avoiding explosions in
potentially explosive atmospheres in accordance with EU Directive
2014/34/EU (ATEX).
Explosion protection
This symbol identifies information about avoiding explosions in
potentially explosive atmospheres in accordance with the
Equipment and Protective Systems Intended for use in Potentially
Explosive Atmospheres Regulations 2016.
Explosion protection
This symbol identifies information about avoiding explosions in
potentially explosive atmospheres in accordance with Technical
Regulation ТРТС012/2011.
General hazard
In conjunction with one of the signal words this symbol indicates a
hazard which will or could result in death or serious injury.
Electrical hazard
In conjunction with one of the signal words this symbol indicates a
hazard involving electrical voltage and identifies information about
protection against electrical voltage.
Machine damage
In conjunction with the signal word CAUTION this symbol indicates
a hazard for the machine and its functions.

2 Safety
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2 Safety
!DANGER
All the information contained in this section refers to hazardous situations.
In addition to the present general safety information the action-related safety
information given in the other sections must be observed.
2.1 General
▪This operating manual contains general installation, operating and maintenance
instructions that must be observed to ensure safe operation of the system and
prevent personal injury and damage to property.
▪Comply with all the safety instructions given in the individual sections of this
operating manual.
▪The operating manual must be read and understood by the responsible specialist
personnel/operators prior to installation and commissioning.
▪The contents of this operating manual must be available to the specialist
personnel at the site at all times.
▪Information and markings attached directly to the product must always be
complied with and kept in a perfectly legible condition at all times. This applies
to, for example:
– Arrow indicating the direction of rotation
– Markings for connections
– Fitting direction
▪The operator is responsible for ensuring compliance with all local regulations not
taken into account.
2.2 Intended use
▪This product must only be operated within the limit values stated in the technical
product literature for the ambient temperature, fluid handled, speed, density,
pressure, temperature and in compliance with any other instructions provided in
the operating manual or other applicable documents.
2.3 Personnel qualification and training
▪ All personnel involved must be fully qualified to install, operate, maintain and
inspect the product this manual refers to.
▪The responsibilities, competence and supervision of all personnel involved in
transport, installation, operation, maintenance and inspection must be clearly
defined by the operator.
▪Deficits in knowledge must be rectified by means of training and instruction
provided by sufficiently trained specialist personnel. If required, the operator can
commission the manufacturer/supplier to train the personnel.
▪ Training on the product must always be supervised by specialist technical
personnel.
2.4 Consequences and risks caused by non-compliance with this manual
▪Non-compliance with these operating instructions will lead to forfeiture of
warranty cover and of any and all rights to claims for damages.
▪Non-compliance can, for example, have the following consequences:
– Hazards to persons due to electrical, thermal, mechanical and chemical
effects and explosions
– Failure of important product functions
– Failure of prescribed maintenance and servicing practices
– Hazard to the environment due to leakage of hazardous substances

2 Safety
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2.5 Safety awareness
In addition to the safety information contained in this operating manual and the
intended use, the following safety regulations shall be complied with:
▪Accident prevention, health regulations and safety regulations
▪Explosion protection regulations
▪Safety regulations for handling hazardous substances
▪Applicable standards, directives and laws
2.6 Safety information for the user/operator
▪Fit protective equipment (e.g. contact guards) supplied by the operator for hot,
cold or moving parts, and check that the equipment functions properly.
▪Do not remove any protective equipment (e.g. contact guards) during operation.
▪Provide the personnel with protective equipment and make sure it is used.
▪Contain leakages of hazardous fluids (e.g. explosive, toxic, hot) so as to avoid any
danger to persons and the environment. Observe all legal requirements.
▪The design of mechanical seals always produces a small amount of leakage.
▪Higher leakage may occur especially in the running-in phase. The leakage must
be drained off in a controlled way
2.7 Safety information for maintenance, inspection and installation
▪Modifications or alterations of the mechanical seal require the manufacturer's
prior consent.
▪Use only original spare parts or parts/components authorised by the
manufacturer. The use of other parts/components can invalidate any liability of
the manufacturer for resulting damage.
▪The operator ensures that maintenance, inspection and installation are
performed by authorised, qualified specialist personnel who are thoroughly
familiar with the manual.
▪Only carry out work on the mechanical seal when the shaft is not rotating.
For mechanical seals installed in pump sets:
▪The pump (set) must have cooled down to ambient temperature.
▪Pump pressure must have been released and the pump must have been drained.
▪When taking the pump set out of service always adhere to the procedure
described in the manual.
▪Decontaminate pumps which handle fluids posing a health hazard.
▪As soon as the work has been completed, re-install and re-activate any safety-
relevant devices and protective devices. Before returning the product to service,
observe all instructions on commissioning.
▪Observe the relevant sections of the corresponding pump operating manual.
2.8 Unauthorised modes of operation
Never operate the mechanical seal outside the limits stated in the data sheet and in
this operating manual.
The warranty relating to the operating reliability and safety of the mechanical seal
supplied is only valid if the mechanical seal is used in accordance with its intended
use.
Any damage caused by dry running shall be excluded from the warranty.

3 Transport/Storage/Disposal
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3 Transport/Storage/Disposal
3.1 Checking the condition upon delivery
1. On transfer of goods, check each packaging unit for damage.
2. In the event of in-transit damage, assess the exact damage, document it and
notify KSB or the supplying dealer and the insurer about the damage in writing
immediately.
3.2 Transport
CAUTION
Improper transport
Damage to the mechanical seal!
▷Only transport the mechanical seal in suitable packaging.
▷Observe the weights, symbols and instructions indicated on the packaging.
▷Use suitable, approved lifting accessories.
KSB’s standard packaging is suitable for dry transport ,e.g. by truck, rail, air. Special
packaging can be provided if specified in the contractual agreement.
CAUTION
Removing transport locks too early
Damage to previously locked components during transport!
▷If transport locks are fitted, do not remove them too early.
3.3 Storage/preservation
CAUTION
Improper storage
Damage due to humidity, vermin, corrosion and contamination!
▷Avoid outdoor storage.
▷Observe, check and record the storage conditions.
▷Regularly check the packaging for any damage.
▷Regularly check the humidity indicator of shrink-wrapped objects. The relative
humidity should be <50%.
▷If the relative humidity indicated for shrink-wrapped objects >50%, have the
equipment repacked by the manufacturer.
CAUTION
Improper storage
Impairment of O-rings' sealing function!
▷Do not store O-rings together with chemicals, solvents, fuels, acids, etc.
▷Protect O-rings from light, in particular from direct sun exposure and strong
artificial light high in ultraviolet rays.
▷Check the O-rings for damage before they are fitted.

3 Transport/Storage/Disposal
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CAUTION
Wet, contaminated or damaged openings and connections
Damage to the mechanical seal!
Risk of embrittlement! Damage to elastomers!
▷Only open screw plugs and connections at the mechanical seal at the time of
installation.
▷Avoid opening screw plugs, connections and similar before that time.
We recommend taking the following measures for storing the mechanical seal:
For storing the mechanical seal observe standards ISO2230 and DIN7716.
Store the mechanical seal in its original packaging, placed on a level surface in a dry,
protected room with constant conditions that meet the following requirements:
▪Relative humidity <65%
▪Temperature between 15°C and 25°C
▪Moderately vented atmosphere
▪Dust-free and vermin-free
If properly stored indoors, the equipment is protected for a maximum of 36months.
New mechanical seals are supplied by our factory duly prepared for storage.
3.4 Return to supplier
1. Remove the used mechanical seal from the system.
2. Always flush and clean the mechanical seal, particularly if it has been used for
handling noxious, explosive, hot or other hazardous fluids.
3. If the mechanical seal has handled fluids whose residues could lead to corrosion
damage in the presence of atmospheric humidity or could ignite upon contact
with oxygen, the mechanical seal must also be neutralised and dried with
anhydrous inert gas.
4. Always complete and enclose a certificate of decontamination when returning
the mechanical seal. Always indicate any safety measures and decontamination
measures taken.
NOTE
If required, a blank certificate of decontamination can be downloaded from the
following web site: www.ksb.com/certificate_of_decontamination

3 Transport/Storage/Disposal
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3.5 Disposal
WARNING
Fluids handled, consumables and supplies which are hot and/or pose a health
hazard
Hazard to persons and the environment!
▷Collect and properly dispose of flushing fluid and any fluid residues.
▷Wear safety clothing and a protective mask if required.
▷Observe all legal regulations on the disposal of fluids posing a health hazard.
1. Dismantle the mechanical seal.
Collect greases and other lubricants during dismantling.
2. Separate and sort the mechanical seal materials, e.g. by:
- Metals
- Plastics
- Greases and other lubricants
3. Dispose of materials in accordance with local regulations or in another
controlled manner.

4 Description
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4 Description
4.1 General description
▪KSB mechanical seal
Mechanical seal for installation in pump sets and other rotating machinery in
accordance with the manufacturer's instructions.
4.2 Product information as per Regulation No. 1907/2006(REACH)
For information as per chemicals Regulation (EC) No. 1907/2006 (REACH), see https://
www.ksb.com/ksb-en/About-KSB/Corporate-responsibility/reach/ .
4.3 Designation
Example: SB120-124M1-4STC-A
Table4: Designation key
Code Description
S Design
K Short overall length
N Normal overall length
S Special overall length
B Type
U Unbalanced
B Balanced
120 Smallest inside diameter of the seal
124 Smallest inside diameter of the primary ring
M Direction of rotation
M Bi-directional with multi-spring arrangement
S Bi-directional with single spring
L Direction of rotation anti-clockwise
R Direction of rotation clockwise
1 Anti-twist lock of mating ring
0 Without lock
1 With lock
4STC Type series, type
A Primary ring carrier, axially secured against reversing pressure
A Axially secured
Blank Not axially secured
4.4 Materials
▪Depending on the application
▪See product literature of the pump
▪Selection of suitable material variant on request
4.5 Design details
Design
▪Mechanical seal in modular design
▪Single seal or in combination with another seal in tandem arrangement to API
Plan52
▪Stationary type
▪Bi-directional

4 Description
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▪Axial movability +/-2.5mm
▪Torque transmission via cup point grub screws
▪Multi-spring arrangement
4.6 Configuration and function
12
3
45
6
7
8910 11
1213
1415
Fig.1: Cross-section of 4STC with axially secured primary ring carrier
Design Mechanical seal for installation in pump sets and other rotating machinery in
accordance with the manufacturer's instructions.
KSB’s mechanical seal 4STC is a component mechanical seal that has been specially
developed for use in pumps of the AmarexKRT, Sewatec and Amacan type series.
KSB’s 4STC mechanical seal is available as a variant with axially secured primary ring
carrier, a variant without axially secured primary ring carrier, and a variant with
clamped mating ring carrier.
Function Primary ring 10 is the axially movable sealing ring which is pressed against mating
ring 9 by springs 12. O-rings 11 and 14 are fitted for secondary sealing. On type series
4STC thrust ring 13 engages with primary ring 10 and primary ring carrier 3, thus
preventing rotation of primary ring 10 without hindering its axial movability. Sealing
between primary ring carrier 3 and discharge cover 2 is provided by O-ring 4. On the
variant with axially secured primary ring carrier, the primary ring carrier is fitted to
the discharge cover with bolts 1. On the variant without axially secured primary ring
carrier, the primary ring carrier is guided into the discharge cover. Here, O-ring 4
transmits the torque. Mating ring 9 is fitted in mating ring carrier 8. Pin 5 transmits
the torque between these two components. The space between the two components
is sealed by O-ring 14. Mating ring carrier 8 is fitted on shaft 7 and fastened with
grub screw 6. Grub screw 6 provides axial fastening and also transmits the torque. O-
ring 15 provides sealing between the mating ring carrier and the shaft.

5 Installation/Dismantling
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5 Installation/Dismantling
NOTE
Priority shall be given to the installation instructions and/or installation sequence in
the documents of the pump set into which this mechanical seal is to be installed.
This also applies to the dismantling instructions and/or dismantling sequence.
5.1 Permissible aids
CAUTION
Impermissible cleaning agents
Damage to the seal faces at the mechanical seal!
▷For removing minor contamination use only paper tissues and ethyl alcohol.
▷Do not use dirty cleaning cloths or cleaning cloths that leave behind lint.
CAUTION
Impermissible assembly aids
Sealing elements made of ethylene propylene diene rubber perishing or swelling
up!
▷Never let sealing elements come into contact with mineral oil base lubricants.
▷Use permissible lubricants only.
▷Verify that the assembly aids are silicon-free.
▪Lubricants2)
– Permanent lubricants, such as non-mineral grease (Klübertemp GR555) are
used for elastomers that do not serve to transmit the torque. Examples are
mating rings with an anti-twist lock or primary rings that move axially
relative to the pump components.
– Non-permanent lubricants such as a soap solution, for example, are used for
elastomers that serve as a sealing element and, in addition, transmit the
torque. An example would be a mating ring without anti-twist lock.
▪Recommended cleaning agent for seal faces and grub screws: ethyl alcohol
▪Thread-locking agent: Loctite, No. 243
▪Open-ended wrench, ring spanner, socket wrench (cleaned, no impact tools)
▪Torque wrench (cleaned)
5.2 Prerequisites
▪Chamfered ends to EN12756
▪Installation dimensions to DIN EN 12756, except 5A-OM, 5B-RC (pump-specific
installation dimensions);
▪Surface roughness of pump components to DINEN12756
▪Shaft run-out to ISO5199:
– Shaft diameter ≤50mm: 0.05mm max.
– Shaft diameter 50 to 100mm: 0.08mm max.
– Shaft diameter >100mm: 0.10mm max.
▪Face run-out of the shaft in relation to the vertical connection surface of the
casing:
2Lubricants must be compatible with all fluids used. They must not be aggressive to the secondary sealing
elements.

5 Installation/Dismantling
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– Shaft speed ≤750rpm: 0.2mm max.
– Shaft speed >750rpm to 1000rpm: 0.15mm max.
– Shaft speed >1000rpm to 1500rpm: 0.08mm max.
– Shaft speed >1500rpm to 3000rpm: 0.025mm max.
▪Permissible centre offset between the pump casing and the shaft:
– Max. 0.2mm for seals without pumping ring
– Max. 0.1mm for seals with pumping ring
▪The seal faces are clean and have not been touched with fingers.
▪The mechanical seal is in proper condition and complete.
▪The elastomers are free from any contamination, cracks, softening, hardening,
stickiness and discolouration.
▪The mechanical seal has been placed down on a clean and level surface.
5.3 Installing the mechanical seal
CAUTION
Use of grease or other permanent lubricants
Torque transmission impeded/ overheating of and damage to the pump!
▷Never use grease or other permanent lubricants for fitting the torque-
transmitting elements of a mechanical seal.
▷Use soft soap to reduce any friction caused during assembly.
▷Never coat the mechanical seal faces with grease or oil.
üThe relevant documentation for installing the mechanical seal is being observed.
üThe back pull-out unit has been removed from the pump casing and safely
positioned and secured in a horizontal position.
üThe original KSB’s mechanical seal 4STC is fully assembled and undamaged.
üAssembly aids are available.
NOTE
If any installation instructions or an installation sequence are specified in the
product literature of the pump/machinery into which the mechanical seal is to be
installed, they must be observed.
1. Properly remove any corrosion or wear.
2. Clean the seal faces with a suitable paper tissue and, if required, ethyl alcohol.
3. Wet O-ring 412.55 and suction cover 162 with a non-permanent lubricant (e.g. a
water/soap mixture).
4. Press the assembly consisting of primary ring carrier 473, primary ring 472, thrust
ring 474, springs and O-rings 412 into the seat at suction cover 162. If necessary,
use a spacer sleeve and elastic intermediate element to protect the seal faces.
NOTE
The seal faces must not be damaged (score mark, etc). The assembly must not be
pressed into the seat by pressing on the primary ring (risk of fracture). The force for
mounting it must be applied via the primary ring carrier.
5. Fasten primary ring carrier 473 to suction cover 162 with hexagon head bolts
901. Tighten the bolts crosswise in several increments. Observe the tightening
torques. This step does not apply to the variant without axially secured primary
ring carrier.
6. Check the seal face for any damage. Clean it again if required.

5 Installation/Dismantling
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7. Check that primary ring 472 is correctly seated.
8. Wet O-ring 412.54 and the corresponding surface on shaft 210 with a suitable,
non-permanent lubricant.
9. Slide the rotating assembly of the seal, comprising mating ring carrier 476,
mating ring 475 and O-rings 412 onto shaft 210 as far as it will go.
10. Preload the rotating assembly with an assembly aid to match the installation
dimension. This step does not apply to the variant with clamped mating ring
carrier. In this case, the installation dimension and torque transmission is
ensured by mounting impeller 230.
11. Tighten grub screws 904, observing the installation dimension and tightening
torques.
NOTE
Do not re-use cup point grub screws!
Used grub screws must be replaced by new cup point grub screws.
ðCup point grub screws must not be re-used. Repeated tightening can impair
the reliability of force transmission.
12. Carry out further installation instructions given in the pump’s operating manual.
5.4 Removing the mechanical seal
The rules of sound engineering practice and the pump manufacturer's general
provisions apply. Tidiness and cleanliness are essential for proper execution of the
installation work.
üThe operating manual for the pump set is on hand.
üThe pump has been prepared in accordance with the operating manual for
removing the mechanical seal.
NOTE
If any dismantling instructions and/or a dismantling sequence are specified in the
product literature of the pump/machinery into which the mechanical seal is to be
installed, they must be observed.
1. Undo grub screws 904. Pull mating ring carrier 476 and mating ring 475 off shaft
210. For the variant with clamped mating ring carrier, pull the mating ring
carrier together with the mating ring directly off the shaft.
2. On mechanical seals with axially secured primary ring carrier 473 undo hexagon
head bolts 901.
3. Use the jacking threads to remove the primary ring carrier.
4. On mechanical seals without axially secured primary ring carrier, use assembly
aids to remove the primary ring carrier. Another option of removing the primary
ring carrier is to remove the discharge cover and apply pressure to the rear side
of the primary ring carrier.
5. Carry out further dismantling instructions given in the pump’s operating
manual.
5.5 Tightening torques
Table5: Tightening torques
Thread [Nm]
M5 4
M6 8
M8 15
M10 20
M12 25

6 Operation
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6 Operation
6.1 Safety instructions for operation
CAUTION
Air intake via the seal faces
Dry running of the seal and consequential seal failure!
▷For single seals the pressure in the seal chamber of the pump must always be
higher than the ambient pressure.
CAUTION
Unsuitable fluid to be sealed off
Damage to the machinery!
▷Take appropriate measures to ensure that the fluid to be sealed off at the
mechanical seal is in liquid condition no matter what the operating status of
the pump. This applies in particular when starting up and stopping the pump.
▷If the fluid to be sealed off forms deposits while the pump set cools down or
during standstill of the pump set, the seal chamber must be flushed through
with a clean liquid. The quantity and type of flushing liquid has to be defined
by the operator for the specific material combination of the mechanical seal.
CAUTION
Excessive rise in temperature
Damage to the mechanical seal!
Dry running or damage to the elastomers, incrustations at the seal faces, etc.
▷Shut down the pump as described in the operating manual.
NOTE
If the operating limits indicated are observed and the instructions given in this
manual are complied with, the mechanical seal can be expected to give trouble-free
operation. If the values during operation are not within the specified limits, the
mechanical seal must be removed from the system and sent to KSB for inspection.
6.2 Emissions
WARNING
Incorrect handling of the fluid to be sealed off
Risk of injury!
▷If the fluid to be sealed off and/or the buffer fluid have to meet the
requirements of the German Hazardous Substances Regulations, the regulations
on handling hazardous substances (safety data sheets to Directive 91/155/EEC)
and the accident prevention regulations must be heeded.
NOTE
If a reduction in leakage cannot be observed or if other failures occur, the
mechanical seal must be shut down, removed from the system and sent to KSB for
inspection.

6 Operation
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NOTE
Any leakage must be drained off in a controlled way and safely disposed of.
Components which may come into contact with the seal leakage must either be
corrosion-resistant or must be adequately protected.
▪For physical and technical reasons a mechanical seal cannot be leak-free.
▪Leakage can be either in liquid or gaseous form. Its aggressiveness corresponds to
that of the fluid to be sealed off.
▪The quantity of leakage is influenced by several factors:
– Seal selection
– Manufacturing tolerances
– Operating statuses
– Smooth running of the pump
▪In the running-in phase of the mechanical seal higher leakage can occur.
6.3 Operating limits
NOTE
Always observe the operating limits in the product literature and the other
applicable documents.
NOTE
The following values are limits that depend on the seal face materials and
elastomer materials. As the characteristics influence each other, operation at
minimum/maximum limits is not possible for all characteristics at the same time.
Table6: Operating limits (nominal diameter, sliding velocity, maximum pressure to be sealed off and temperature
limits depending on the material combination and fluid.)
Type series v3) Max. pressure to be sealed off T4)
Carbon/SiC SiC/
SiC
SiC/WC Max.
[m/s] [bar] [bar] [bar] [°C]
4STC 20 14 14 14 +200
3Sliding velocity
4Fluid temperature

7 Maintenance
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7 Maintenance
7.1 Maintenance/inspection
NOTE
The operator is responsible for conducting checks.
▪The mechanical seal is low in maintenance. Replace wear parts as necessary.
▪Proper operation includes regular checks of temperature and leakage (drainage)
of the mechanical seal.
▪When a system maintenance inspection or pump maintenance inspection is
conducted, the mechanical seal should also be inspected. The seal faces should be
reworked and all elastomer joint rings and springs should be replaced by new
ones. KSB is available for inspecting the mechanical seal.

8 Trouble-shooting
19 of 26
4STC
1974.893/03-EN
8 Trouble-shooting
WARNING
Improper work to remedy faults
Risk of injury!
▷For any work performed to remedy faults, observe the relevant information
given in this operating manual and/or in the product literature provided by the
accessories manufacturer.
NOTE
Prior to conducting any work on the mechanical seal during the warranty period
contact the manufacturer. KSBService will be pleased to help you. Non-compliance
with this instruction will lead to forfeiture of any and all rights to claims for
damages.
NOTE
For any failures you cannot remedy or whose cause cannot be identified, contact
the responsible KSBservice centre.
What to do in the event of a fault/malfunction
▪Determine and document the nature of the fault/malfunction.
▪Monitor the development of leakage quantity. If necessary, shut down the pump
as described in the operating manual.
A steady flow of leakage indicates mechanical seal damage.
Maintenance work, service work and installation work by KSBService
▪KSB Service GmbH | Service Center Pegnitz
E-mail: [email protected]
▪KSB Service LLC | Service Center Abu Dhabi
E-mail: [email protected]
Contact for general queries:
▪E-mail: [email protected]
Further contact addresses:
▪https://www.ksb.com/en-global/contact

9 Related Documents
20 of 26 4STC
1974.893/03-EN
9 Related Documents
9.1 General drawings with list of components
9.1.1 Variant with axially secured primary ring carrier
A
A
1
901
Fig.2: Cross-section axis
901
350
473
562.52
210
412.52
472
475
476
412.55
477
474
412.54
412.53
904
562.53
Fig.3: Sectional drawing
Table7: List of components
Part No. Description Part No. Description
1 Jacking thread 475 Mating ring
210 Shaft 476 Mating ring carrier
350 Bearing housing 477 Spring for mechanical seal
412.52/.53/.54/.55 O-ring 562 Parallel pin
472 Primary ring 901 Hexagon head bolt