Vag ZETA Manual

KAT-B2 2410 Edition 8 - 30-11-2017
VAG ZETA®Knife Gate Valve
Version with AUMA electrical multiturn
actuator (EA)
Operating and Maintenance Instructions

Table of Contents
VAG reserves the right to make technical changes and use
materials of similar or better quality without prior notice.
The pictures used are typical and non-binding.
1 General 3
1.1 Safety 3
1.2 Proper use 3
2 Transport and Storage 3
2.1 Transport 3
2.2 Storage 3
3 Product features 3
3.1 Features and function description 3
3.2 Applications 4
3.3 Permissible and impermissible modes of operation
4
4 Installation into the pipeline 4
4.1 Conditions required on site 4
4.2 Installation location 4
4.3 Installation position 4
4.4 Assembly instructions and fittings 5
5 Putting the valve into operation 7
5.1 Visual check of the valve 7
5.2 Putting the electrical multiturn actuator into opera-
tion 7
5.3 Emergency manual operation via the handwheel 7
5.4 Function check 7
6 Maintenance and service 8
6.1 General safety instruction 8
6.2 Inspection- and operation intervals 8
6.3 Maintenance and replacement of spare parts 8
6.3.1 Testing for easy movement 8
6.3.2 Repairing a leak at the outlet of the knife 8
6.3.3 Repairing a leak at the knife passage 8
6.3.4 Cleaning and lubricating 8
7 Trouble-shooting 10
8 How to contact us 11

VAG Operating and Maintenance Instructions • 3
For knife gate valves with premounted electrical multiturn
actuators, the storage instructions issued by the respective
actuator manufacturer must also be observed!
3 Product features
3.1 Features and function description
The VAG ZETA®Knife Gate Valve is a gate valve in full-flange de-
sign and can thus be applied either as wafer type in-between two
flanges or for pipeline-end installation without additional counter
flange and at full operating pressure. Due to its bi-direc- tional
sealing arrangement, any installation position is possible. The kni-
fe slides in a U-profiled gasket made of elastomer bet- ween the
two body parts. Sealing in flow direction is pressure-supported
and soft sealing.
The sealing of the knife at the outlet of the body is realised by a
defined and elastically prestressed lateral seal. This seal can be
readjusted during operation and be easily replaced without dis-
mantling the valve from the pipeline.
Warning!! Ensure the pipeline is depressurised before
performing any replacement works.
In case of suspended installation of the valve, knife must be
field-secured against falling out.
The lateral seal is factory-adjusted (pretensioned) with a sealing
force equal to the nominal pressure (PN). In order to reduce the
operating forces and the wear of the lateral seal, this pretension
may later be adjusted to the actual operating pressure. To do this,
loosen the screws holding the thrust piece accordingly.
The electric multiturn actuator is directly mounted on the valve.
The connection dimensions between the multiturn actuator and
the valve are according to DIN ISO 5210.
The shut-off of the multiturn actuator in closing direction is
factory-adjusted in dependence of the torque. In opening
direction, the actuator is shut off in dependence of the po-
sition. The respective final positions „OPEN“ and „CLOSE“
are signalled by a limit switch!! This factory adjustment
must be observed for the planning and configuration of the
electronic control!
The factory-adjusted torque-controlled shut-off of the multiturn
actuator in „closed“ position guarantees the defined pressing of
the bore seal and prevents premature leaking of the valve. This
adjustment ensures that the knife exerts a constant closing force
on the bore seal which can neither be affected by the com- pres-
sion set of the seal nor by wear and tear of the stem nut or any
other positional changes.
The position-controlled shut-off of the multiturn actuator in
„closed“ position is also available upon the customer‘s express
request. However, we expressly point out that we assume no lia-
bility for the failures that usually result from this shut-off method,
such as leaks due to the compression set of the bore seal and the
required readjustment of the limit position.
For the user‘s information, a clearly visible label has been atta-
ched to the cover of the switch mechanism of the electric actu-
ator (see Fig. 1), bearing the adjustment information, adjustment
torques etc.. The screws of the switch mechanism cover are fac-
tory-sealed with sealing wax. Breaking this seal by unauthorised
opening will result in the loss of warranty.
1 General
1.1 Safety
These operation and maintenance instructions must be observed
and applied along with the general „VAG Installation and Ope-
ration Instructions for Valves“. Arbitrary alterations of this pro-
duct or parts supplied are not allo- wed. VAG will not assume
any liability for consequential damage due to non-compliance
with these instructions. When using this valve, the generally
acknowledged rules of technology have to be observed (e.g.
DIN standards, DVGW data sheets, VDI directives, etc.). The in-
stallation must only be carried out by qualified technical staff.
For further technical information such as dimensions, materials or
range of application, please refer to document KAT 2410-A.
1.2 Proper use
The VAG ZETA®Knife Gate Valve is a valve for installation into the
pipeline, either as wafer type, fitted between flanges, or for end-
of-line applications.
In its standard version, this valve is designed for the shut-off of
pressurised pipelines. For technical data concerning the operating
limits (e.g. operating pressure, medium or temperature) please re-
fer to the product-related documentation KAT 2410-A. Alternative
operating conditions and applications require the manufacturer‘s
written approval.
The valve has been designed for operation in liquids. If it
is operated temporarily in dry media, increased operating
forces as well as increased wear of the lateral seal and the
U-profile seal are to be expected. Permanent dry operation
is impermissible for technical reasons!
2 Transport and Storage
2.1 Transport
The transportation of the valve to the installation site must be un-
dertaken in suitable and stable packing corresponding to the val-
ve size. The packing must guarantee protection against weat- her
influences and damage from external forces.
In some cases, e.g. overseas transport, with specific climatic in-
fluences, the valves must be protected by wrapping them in plas-
tic film and adding a desiccant.
In case of premounted drives or actuators, these have to be stored
in a safe way which prevents the connection areas from being ex-
posed to transverse loads. The factory-applied corrosion protec-
tion coating must be especially well protected at all times. When
valves with pre-mounted electrical actuators are moved, the lifting
equipment must not be attached to the multiturn actuator and not
to the handwheel!
2.2 Storage
Store the ZETA®Knife Gate Valve with the knife in the closed po-
sition. Protect the elastomeric parts (gaskets) against direct sun-
light; failure to do this may deteriorate the seals and thus affect
proper and long-term function.
Store the valve in a dry and well-aerated location. Protect the val-
ve from direct radiator heat. Protect any assembly units impor-
tant for the function such as the stem, stem nut, gaskets or knife
against dust and other dirt by adequate covering.
Connect the multiturn actuator to the mains supply immediately
after assembly so that its heating can prevent the formation of
condensation water!

VAG Operating and Maintenance Instructions • 4
4.2 Installation location
The installation location of the valve must provide enough space
for operation, later function tests and maintenance works (e.g. re-
adjusting the lateral seal). If the valve is to be installed outside, it
has to be protected by adequate covering against direct weather
influences such as icing. If the valve is mounted as an overflow
installation, higher operation forces and higher wear and tear of
the relatively moving parts must be expected. This fact is to be
taken into account when determining the maintenance intervals
If the valve is to be installed at pipeline end, make sure that the
free outlet is absolutely inaccessible for anybody.
Warning!! The nominal pressure on the closed valve must not be
exceeded (see document KAT 2410-A). In case of a pressure test
in the pipeline using higher pressures than the admissible nomi-
nal pressure, close the gate valve with a cover and slightly open
the knife during the test.
4.3 Installation position
If the valve is to be installed in a horizontal pipeline and if the
media conveyed contain solid particles (e.g. sand, etc.), the valve
should not be inclined more than 60° from the vertical position
(see Fig. 2). This allows the continuous flushing of the operating
area and reliable guiding of the knife.
In different installation positions, especially if the valve is sus-
pended or installed horizontally in a vertical pipeline, increased
deposition of solids on the knife cannot be avoided. This increa-
ses the risk of malfunction (e.g. wear of the lateral seal, increa- sed
operating forces, etc.) and requires more frequent maintenance.
Attention: To ensure its proper function at all times, the
valve should not be installed outside the permissible range.
In case of deviating installation positions, always contact
the manufacturer for technical coordination, providing pre-
cise information about the installation position, operating
conditions and quality of the medium (especially about its
solids content).
If assembly and maintenance work are carried
out on valves with a suspended installation positi-
on, the knife must be secured on site against fal-
ling out when the lateral seal is being replaced.
Attention! Exception!
VAG ZETA®control valve with VAG control orifice. The ZETA®control
valve must be installed in a vertical position as otherwise its func-
tion may be affected by the accumulation of dirt upstream of the
control orifice.
Concerning the installation direction of the ZETA®control valve,
the following instructions must be observed:
• The control orifice must be positioned in flow direction
downstream of the knife!
• The control orifice must be positioned in pressure direction
(direction of action of the differential pressure after closing)
downstream of the knife!
3.2 Applications
In its standard version, the VAG ZETA®Knife Gate Valve with NBR
sealing material can be used for the following media:
• Water, raw water, cooling water, municipal waste water,
grease- and oil-containing media, weak acids and bases
For alternative operating conditions and applications, please con-
tact the manufacturer.
3.3 Permissible and impermissible modes of
operation
Avoid the exertion of excessive force caused by using ex-
tensions on the operating elements, as this may dama- ge
the valve due to overload.
The ZETA®Knife Gate Valve with electric multiturn actuator
is suitable for „Open/Close“ operation. For special control
applications, special versions such as the ZETA®control
with control orifice are required.
The maximum operating temperatures and operating pressures
specified in the technical documentation must not be exceeded.
The closed knife gate valve must not be exposed to pressures ex-
ceeding its nominal pressure (see Table 3 / nominal pressure PN).
Upon delivery, the tight sealing of the valve is only guaran- teed
up to its maximum permissible operating pressure.
The valve has been designed for operation in liquids. If it
is operated temporarily in dry media, increased operating
forces as well as increased wear of the lateral seal and the
U-profile seal are to be expected. Permanent dry operation
is impermissible for technical reasons!
4 Installation into the pipeline
4.1 Conditions required on site
When installing the valve between two pipeline flanges, these must
be coplanar and in alignment. If the pipes are not in align- ment,
they must be aligned before installation of the valve, as otherwise
this may result in impermissibly high loads acting onto the valve
body during operation and eventually even lead to fracture.
The valve is to be installed tensionless into the pipeline. No pipe-
line forces must be transmitted from the pipeline onto the valve.
The space between the flanges should be wide enough to prevent
damage to the coating of the flange gasket frames during instal-
lation.
In case of works around the valve causing dirt (e.g. painting, ma-
sonry or working with concrete), the valve must be protected by
adequate covering.
Picture 1: Example of a label showing the adjustments of the electric actuator
Factory-adjusted drive!!!!
Unauthorised changes result in
the loss of warranty
Position dependent
Torque-dependent
Torque adjusted
Control Open Closer
60 ° 60 °
Picture 2: Installation position of the VAG ZETA®Gate Valve

VAG Operating and Maintenance Instructions • 5
4.4 Assembly instructions and fittings
The valve is bidirectional and therefore can be installed in any in-
stallation position.
Check the valve for any possible transport or storage damage be-
fore installation. Protect the valve against dirt on site by ade- qua-
te covering until installation.
When the valve is being installed, the functional parts such as the
stem, stem nut, gasket and knife must be free from dust and dirt.
For the installation of the ZETA®Knife Gate Valve you will need
adequate load suspension devices (e.g. ring bolt in the blind hole)
as well as transport and lifting equipment. Lifting the valve for ex-
ample at the handwheel may lead to damage and impairment of
its function.
When repainting the valve, make sure that no functional parts
such as the stem, stem nut, gasket, knife or piston rod are cover-
ed by the paint.
When installing an extension rod to the valve, mount it perpendi-
cularly to the stem axis above the fixing point.
When installing an extension rod to the valve, mount it perpendi-
cularly to the stem axis above the fixing point.
When connecting the valve to the pipeline flanges with through-
holes, use hexagon head screws and nuts with washers on both
sides from flange to flange.
When connecting the valve to the pipeline flanges with blind th-
read holes, use stud bolts with washers and nuts for a safe and
reliable installation (see example 3 at fig. 3). Screw the stud bolts
completely to the ground of the blind thread holes of the valve.
This guarantees an optimum connection, as the threads are used
over their whole effective depth. Then align the valve with the flan-
ge by using the stud screws as orientation pins.
Using hexagon head screws in case of blind thread holes can lead
to leaky connections (see example 1 and 2 at fig. 3).
Fasten the screws carefully and evenly crosswise, thus preven-
ting unnecessary tensions and cracks or fractures.
The pipeline must in no case be pulled towards the valve. If the
gap between the valve and the flange is too wide, this should to
be compensated by thicker gaskets.
We recommend steel-reinforced rubber gaskets accor-
ding to DIN EN 1514-1 shape IBC for sealing. If the flan-
ges are crimped, these gaskets must be used.
For the kind and the sizes of the required connection parts
for each kind of installation (as wafer type in-between two
flanges or for pipeline end installation), see the following
tables (Table 1 and Table 2).
Flanges Wafer-type
Connecting dimensions acc. to DIN EN
1092-1 Typ 11 Blind thread hole lThrough hole ¡
DN
bolt circle &
flange outside
&
thread height
T
Threaded pin DIN 939 Hexagon nut
DIN 939
Hexagon head
screw
DIN EN 24014
Hexagon nut
DIN 934
qty dimension qty size qty dimension qty size
50 125 165 10 8 M16 x 35 8 M16 - - - -
65 145 185 12 8 M16 x 35 8 M16 - - - -
80 160 200 12 8 M16 x 40 8 M16 4 M16 x 120 4 M16
100 180 220 14 8 M16 x 40 8 M16 4 M16 x 130 4 M16
125 210 250 15 8 M16 x 45 8 M16 4 M16 x 130 4 M16
150 240 285 15 8 M20 x 45 8 M20 4 M20 x 130 4 M20
200 295 340 15 8 M20 x 45 8 M20 4 M20 x 150 4 M20
250 350 395 17 16 M20 x 50 16 M20 4 M20 x 160 4 M20
300 400 445 22 16 M20 x 55 16 M20 4 M20 x 170 4 M20
350 460 505 22 20 M20 x 55 20 M20 6 M20 x 170 6 M20
400 515 565 26 20 M24 x 60 20 M24 6 M24 x 200 6 M24
500 620 670 30 28 M24 x 65 28 M24 6 M24 x 220 6 M24
600 725 780 32 28 M27 x 70 28 M27 6 M27 x 260 6 M27
700 840 895 27 32 M27x80 32 M 27 8M27 x 300 8M 27
800 950 1015 30 32 M30x90 32 M 30 8M30 x 320 8M 30
900 1050 1115 30 36 M30x90 36 M 30 10 M30 x 340 10 M 30
1000 1160 1230 33 36 M33x100 36 M 33 10 M33 x 360 10 M 33
1200 1380 1455 36 48 M36x110 48 M 36 8M36 x 440 8M 36
1400 1590 1675 39 52 M39x120 52 M 39 10 M39x500 10 M39
Table 1: Connection parts for flange connection, wafer type
Connection parts for flange connection, wafer type
Lengths of screws are for pre-welded flanges acc. to DIN EN 1092-1, PN 10 type 11, washers acc. to DIN 125 (ISO 7090).DN 50...600: Flat gaskets acc. to DIN EN 1514-
1 / PN 10 / shape IBC, thickness 3 mm; DN 700...1400: Flat gasket according to DIN EN 1514-1 / PN 6 / shape IBC, thickness 8 mm, (flange sealing face PN 6)
T
T
DN 700...1400
DN 50...600
Wrong Wrong Right
Picture 3: Assembly of the VAG ZETA®Knife Gate Valve

VAG Operating and Maintenance Instructions • 6
lBlind thread hole
¡Through hole
Picture 4: Blind thread hole and through hole
DN 50...65
DN 80...200
DN 250...300 DN 400 DN 500...600
DN 700 DN 800 DN 900 DN 1000
Flanges Pipeline end installation
Connecting dimensions acc. to DIN EN
1092-1 Typ 11 Blind thread hole lThrough hole ¡
DN
bolt circle
&
flange
outside &
thread
height T
Threaded pin DIN 939 Hexagon nut
DIN 939
Hexagon head
screw
DIN EN 24014
Hexagon nut
DIN 934
qty dimension qty size qty dimension qty size
50 125 165 10 4 M16 x 35 4 M16 - - - -
65 145 185 12 4 M16 x 35 4 M16 - - - -
80 160 200 12 4 M16 x 40 4 M16 4 M16 x 90 4 M16
100 180 220 14 4 M16 x 40 4 M16 4 M16 x 90 4 M16
125 210 250 15 4 M16 x 45 4 M16 4 M16 x 100 4 M16
150 240 285 15 4 M20 x 45 4 M20 4 M20 x 100 4 M20
200 295 340 15 4 M20 x 45 4 M20 4 M20 x 110 4 M20
250 350 395 17 8 M20 x 50 8 M20 4 M20 x 120 4 M20
300 400 445 22 8 M20 x 55 8 M20 4 M20 x 130 4 M20
350 460 505 22 10 M20 x 55 8 M20 6M20 x 130 6 M20
400 515 565 26 10 M24 x 60 10 M24 6 M24 x 140 6 M24
500 620 670 30 14 M24 x 65 14 M24 6 M24 x 160 6 M24
600 725 780 32 14 M27 x 70 14 M27 6 M27 x 180 6M 27
700 840 895 27 16 M27x80 16 M 27 8M 27 x 260 8M 27
800 950 1015 30 16 M30x90 16 M 30 8M 30 x 280 8M 30
900 1050 1115 30 18 M30x90 18 M 30 10 M 30 x 300 10 M 30
1000 1160 1230 33 18 M33x100 18 M 33 10 M 33 x 320 10 M 33
1200 1380 1455 36 24 M36x110 24 M36 8 M36x380 8 M 36
1400 1590 1675 39 26 M39x120 26 M39 10 M39x420 10 M 39
Table 2: Connection parts for flange connection, pipeline end installation
Connection parts for flange connection, pipeline end installation
Lengths of screws are for pre-welded flanges acc. to DIN EN 1092-1, PN 10 type 11, washers acc. to DIN 125 (ISO 7090). DN 50...600: Flat gaskets acc. to DIN EN 1514-
1 / PN 10 / shape IBC, thickness 3 mm; DN 700...1400: Flat gasket according to DIN EN 1514-1 / PN 6 / shape IBC, thickness 8 mm, (flange sealing face PN 6)
T
T
DN 700...1400
DN 50...600
DN 1200 DN 1400

VAG Operating and Maintenance Instructions • 7
5 Putting the valve into operation
5.1 Visual check of the valve
Before putting the valve and the electric multiturn actuator into
operation, make a visual inspection of the functional parts. Tho-
roughly clean all parts essential for proper function (such as the
stem, bearing, seals, knife etc.) to remove all dirt.
VAG does not assume any liability for consequential damage
caused by dirt, residue of shot blasting particles or welding
beads on the knife. The valves are thoroughly lubricated at the
factory to ensure trouble-free transport, storage and installation.
However, it might be necessary to lubricate them again when ta-
king them into operation.
Recommended lubricants:
• Knife and seals: Fuchs Chemplex Si 2; Fuchs Notropeen Si 1;
Klüber Unisilikon L 641
• Stem and stem nut: KLÜBERPLEX BE 31-502 for electric
drives Manufacturer: Klüber Lubrication München AG, Germany
Connection to the electrical mains!
Work on electrical devices or equipment must only be per-
formed by skilled persons or specially trained staff under
supervision and in compliance with the electro-technical
rules. Connection to the electrical mains must be perfor-
med in compliance with the operation manual and the cir-
cuit diagram and terminal diagram of the manufacturer of
the electric actuator.
The regulations and directives for operation in potentially
explosive atmospheres must be observed.
After installing the valve, make sure it is properly grounded,
e.g. via the flange connection.
After assembling the multiturn actuator, immediately con-
nect it to the mains so that its heating can prevent the
formation of condensation water!
5.2 Putting the electrical multiturn actuator
into operation
5.2.1 Using the handwheel, first turn the knife of the ZETA®Knife
Gate Valve manually into central position.
5.2.2 Then shortly operate the electrical multiturn actuator to
check the direction of movement of the knife and thus the correct
direction of rotation of the actuator.
Correct: Actuator turns RIGHT (clockwise) = Valve closes
Correct: Actuator turns LEFT (counter-clockwise) = Valve opens
5.2.3 When the direction of rotation is wrong, the polarity of the
connection cables must be reversed.
Warning!!! If the electrical connections are wrongly pola-
rised, the limit switches and torque switch will not work!
5.2.4 The electric actuator can only operate the valve over its ent-
ire length of stroke when the direction of rotation and the polari-
sation are correct.
5.2.5 Operate the valve over its entire length of stroke to check
for smooth movement and the correct final positions „OPEN“ and
„CLOSE“.
5.3 Emergency manual operation via the
handwheel
The diameter of the handwheel for emergency operation is fac-
tory-defined and designed for normal manual forces only.
When the valve is operated via the handwheel of the electric mul-
titurn actuator, it must be taken into account that there is no pro-
tection of the operating mechanism in case the failure moments
are exceeded.
Careful and meticulous operation of the handwheel is therefore
necessary.
The assembly and use of lever extensions (e.g. handwheel rods)
is impermissible.
Should you detect a noticeable resistance when closing the valve
via the handwheel, do not exert higher manual force but turn the
handwheel back into the opposite direction by some turns and
then try to operate the valve again.
If the handwheel keeps blocking, the pipeline should be checked
for obstructions.
5.4 Function check
Before putting the valve into operation, open and close it at least
once over its entire stroke and check for easy movement.
If the pipeline has to undergo a pressure test with water, the maxi-
mum permissible operating pressure (see Table 3) of the valve
must not be exceeded when the knife is open.
The pressure exerted on the closed valve must not exceed the
maximum permissible operating pressure (see Table 3).
The lateral seal of the valve has been factory-adjusted to the
maximum permissible operating pressure / nominal pressure PN
(see Table 3) in the body. For pressure tests with higher pressures
(up to the maximum test pressure for resistance in the body
according to Table 3) the tension of the lateral seal can be increa-
sed on site by turning the screws of the cover clockwise.
DN PN max. admissible Admissible operating temperature Test pressure in
operating for water, waste water and sewage bar with water
overpressure PS sludge Resistance1) Leak-freeness
mm bar °C in body in seat
50...300 10 10 50 15 10
350...400 10 8 50 12 8
500...600 10 6 50 9 6
700...800 10 4 50 6 (4)* 4
900...1000 10 2,5 50 3,75 (2,5)* 2,5
1200, 1400 10 2 50 3,0 2,0
* Guaranteed resistance 1.5 x PN, leak-freeness only up to PN
1) In delivery condition, the leak-freeness of the valve is guaranteed only up to its maximum admissible operating pressure.
Table 3: Field of use

VAG Operating and Maintenance Instructions • 8
After the pressure test, the tension of the lateral seal must be relie-
ved to achieve its original state as otherwise the multiturn actuator
may be overloaded due to increased operating forces.
In general the tension of the lateral seal can be released to adjust
it to the actual operating pressure (see Section 3.1). This reduces
the wear of the seal during operation and lowers the operating
forces of the valve. It also increases the useful life of the valve and
reduces maintenance work on the lateral seal.
6 Maintenance and service
6.1 General safety instruction
Before the performance of inspection and maintenance work on
the valve or on parts mounted to it the pressurised pipeline must
be shut off, depressurised and protected against unintentional re-
start.
Depending on the kind and dangerousness of the medium con-
veyed, all the relevant safety regulations must be com plied with!
After completing the maintenance work and before restart, all con-
nections must be checked for proper and close fit and for leak-
freeness. For restart, perform the steps described under Section
5 for initial startup.
6.2 Inspection- and operation intervals
Due to its mode of operation, it is advisable to operate the valve
over its entire stroke at least four times per year and to check its
components for proper function. Under extreme operation con-
ditions and in case of operation with heavily soiled media, these
operation and function checks are to be performed more frequent-
ly in accordance with the operator‘s experience.
6.3 Maintenance and replacement of spare
parts
6.3.1 Testing for easy movement
During maintenance work performed according to the recom-
mended intervals, the valve should be operated over its entire
stroke. In case of difficult movement, clean and lubricate the stem
and knife.
6.3.2 Repairing a leak at the outlet of the knife
After longer shut-down periods, the seal may be slightly leaky. If
leaks persist even after the valve has been operated several times,
the lateral seal (10) can be easily re-tensioned without dismantling
the valve. To do this, evenly turn the screws of the thrust piece (2)
by approx. ½ turn each until the leaking stops. If it is not possible
to re-tension the thrust piece (2) via the screws, the ent- ire lateral
seal unit (Kit 1, items 10 and 11) has to be replaced. How often the
lateral seal requires readjustment depends on the degree of soiling
of the medium and on the operating conditions. The fact that the
seal has to be readjusted does not constitute a material defect.
Picture 5: Single parts, position
7.2
7.1
6
4
5
3
2
1
9
10
11
8
14
6.3.3 Repairing a leak at the knife passage
If the knife passage leaks, this is mostly due to damage or irre-
parable wear of the U-profiled gasket (9). In this case, the parts of
the entire unit 2 should be replaced. This can only be done when
the valve is dismantled.
6.3.4 Cleaning and lubricating
The rising stem (4) must always be kept free from dirt and well
lubricated.
Depending on the operating conditions, the knife must be clea-
ned and lightly relubricated.
The lubricator of the output drive Shape A (7.1) must be relubri-
cated using a grease gun.
The rising stem moves in axial direction through the casing of the
multiturn actuator. Depending on the nominal width or the length
of stroke, the upper opening of the casing is closed either by a
black threaded cap or a stem protection tube (15). VAG does not
assume any liability for failures resulting from modified or remo-
ved protective devices.
Recommended lubricants::
• Knife and seals: Fuchs Chemplex Si 2; Fuchs Notropeen Si 1;
Klüber Unisilikon L 641
• Stem and stem nut: KLÜBERPLEX BE 31-502 for electric
drives
Manufacturer: Klüber Lubrication München AG, Germany

VAG Operating and Maintenance Instructions • 9
6.3.5 Recommendations for the replacement
of parts (see Table 4/Parts list, spare parts
units)
a) Replacement of lateral seal Unit 1 every 2 years
b) Replacement of U-profiled seal and scraper Unit 2 when necessary
c) Replacement of stem, stem nut, slide bearing Unit 3 when necessary
Under extreme operating conditions, the parts mentioned above
may have to be replaced more frequently.
Pos. Description KIT 1 KIT 2 KIT 3
1Body
2Thrust piece
3Knife
4Rising stem •
5Bolt, washer, split-pin •
6Adapter part
7.1 Output drive shape A for electric acuator
7.2 Electric actuator •
8Scraper profile •
9U-profiled qasket •
10 Lateral seal • •
11 Sliding rod • •
14 Compression profile •
15 Protection cap or stem protection tube
Table 4: Parts list and recommended spare part units

VAG Operating and Maintenance Instructions • 10
7 Trouble-shooting
For all repair and maintenance work, please observe the general
safety instructions described in Section 6.1
Problem Cause Remedial action
The knife does not move /
is jammed
Lateral seal is too tight Evenly unfasten the screws of the thrust piece
Stem or stem nut is damaged
Check the stem for traces of jamming, clean and lubri-
cate the parts, replace the parts if
necessary!
Foreign particle is jammed in the seat Open the valve (up to 10 - 30% of the stroke) and
close it again; repeat this action several times
Knife is blocked by hardened particles in the
medium
Unfasten the thrust piece by unfastening the screws
evenly, slightly hammer against the knife from above
and from the side with a rubber mallet, and try to ope-
rate the valve.
If this does not solve the problem: dismantle the valve,
dismantle the knife, clean it, lubricate it, replace dama-
ged parts.
See also Section 6.1!
High operating forces
Lateral seal is too tight Evenly unfasten the screws of the thrust piece
See also Section 6.1!
Dirt sticks to the knife
Dry run of the knife Open the valve, clean the knife, lubricate it
Stem and stem nut have run dry Lubricate the parts
Leak at the knife passage
Foreign particle is jammed in the seat
Open the valve (up to 10 - 30% of the stroke) and
close it again, repeat this action several times, remove
jammed particle if possible
U profiled gasket is damaged Replace U profiled gasket according to Section
6.3.3
Leak at the outlet of the
knife
Leaking lateral seal
Retighten the lateral seal according to Section
6.3.2
See also Section 6.1!
Damaged lateral seal
Replace the lateral seal according to Section
6.3.2
Clean the knife and lubricate it
See also Section 6.1!
Damaged lateral seal Open the valve, remove the protection panel, clean the
knife and lubricate it

VAG Operating and Maintenance Instructions • 11
8 How to contact us
Head office
VAG-Armaturen GmbH
Carl-Reuther-Str. 1
68305 Mannheim
Germany
Phone: [phone]
Fax: [phone]
[email protected]
http://www.vag-group.com
Service
Our service hotline can be reached 24/7 world-wide. In case of
emergency, please contact us by phone
Service hotline: +49 621 - 749 2222
Service per E-Mail: [email protected]

Edition 7- 12-08-2013
www.vag-group.com
[email protected]