Mankenberg DM 618Z Installation instructions

Original operating manual
spring-actuated pressure control valves
Originalbetriebsanleitung
federgesteuerte Druckregelventile
DM
DM-4.X.23.1 Stand 16.08.2023 www.mankenberg.com

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DM-4.X.23.1 Stand 16.08.2023 www.mankenberg.com
Table of contents EN
1 Introduction ................................................................................................................................................ 4
2 Intended use ............................................................................................................................................... 4
3 Applied standards and directives............................................................................................................. 6
4 Marking of the valve................................................................................................................................... 6
5 Safety instructions..................................................................................................................................... 7
5.1 General precaution............................................................................................................................... 7
5.2 Special safety instructions for the plant operator ................................................................................. 7
5.3 Special hazards.................................................................................................................................... 7
6 Transport and storage ............................................................................................................................... 8
7 Installation .................................................................................................................................................. 9
7.1 General notes....................................................................................................................................... 9
7.2 Installation preparations ....................................................................................................................... 10
7.3 Installation steps .................................................................................................................................. 11
8 Pressure testing the pipeline section....................................................................................................... 13
9 Initial start-up.............................................................................................................................................. 14
10 Normal operation........................................................................................................................................ 16
11 Maintenance................................................................................................................................................ 17
12 Troubleshooting help................................................................................................................................. 19
13 Information on REACH and RoHS ............................................................................................................ 22
13.1 Declaration on the REACH Regulation 1907/2006 .............................................................................. 22
13.2 Declaration on the RoHS Directive 2011/65/EU .................................................................................. 22
14 Further information.................................................................................................................................... 22
15 Know How................................................................................................................................................... 22
15.1 Function ............................................................................................................................................... 22
15.2 Consideration of the design data ......................................................................................................... 23
15.3 Selecting valve type and nominal diameter.......................................................................................... 23
15.4 Selecting rated pressure and valve material ........................................................................................ 23
15.5 Selecting the setting range................................................................................................................... 23
15.6 Selecting elastomer materials .............................................................................................................. 23
15.7 Sense line (control line)........................................................................................................................ 23
15.8 Protecting your system......................................................................................................................... 23
15.9 Protecting the pressure reducing valve................................................................................................ 23
15.10 Cut-off .................................................................................................................................................. 24
15.11 Stellited seat and cone......................................................................................................................... 24
15.12 Mounting position ................................................................................................................................. 24
15.13 Steam operation................................................................................................................................... 24
15.14 Start-up ................................................................................................................................................ 24
15.15 Setting the pressure ............................................................................................................................. 24
15.16 Recommended installation................................................................................................................... 25

Inhaltsverzeichnis DE
1 Einleitung.................................................................................................................................................... 26
2 Bestimmungsgemäße Verwendung ......................................................................................................... 26
3 Angewandte Normen und Richtlinien ...................................................................................................... 28
4 Kennzeichnung der Armatur..................................................................................................................... 28
5 Sicherheitshinweise................................................................................................................................... 29
5.1 Allgemeiner Sicherheitshinweis ........................................................................................................... 29
5.2 Spezielle Sicherheitshinweise für den Betreiber .................................................................................. 29
5.3 Besondere Gefahren............................................................................................................................ 29
6 Transport und Lagerung............................................................................................................................ 30
7 Einbau ......................................................................................................................................................... 31
7.1 Allgemeines.......................................................................................................................................... 31
7.2 Vorbereitung zum Einbau..................................................................................................................... 32
7.3 Schritte beim Einbau ............................................................................................................................ 33
8 Druckprüfung des Rohrleitungsabschnitts ............................................................................................. 35
9 Erste Inbetriebnahme................................................................................................................................. 36
10 Normalbetrieb............................................................................................................................................. 38
11 Wartung....................................................................................................................................................... 39
12 Hilfe bei Störungen .................................................................................................................................... 41
13 REACH- und RoHS-Auskunft .................................................................................................................... 44
13.1 Erklärung zur REACH-Verordnung 1907/2006 .................................................................................... 44
13.2 Erklärung zur RoHS-Richtlinie 2011/65/EU ......................................................................................... 44
14 Weitere Informationen ............................................................................................................................... 44
15 Know-How................................................................................................................................................... 44
15.1 Funktion ............................................................................................................................................... 44
15.2 Berücksichtigung der Designdaten ...................................................................................................... 45
15.3 Auswahl von Ventiltyp und Nennweite ................................................................................................. 45
15.4 Auswahl von Nenndruck und Werkstoff ............................................................................................... 45
15.5 Auswahl des Einstellbereichs............................................................................................................... 45
15.6 Auswahl der Elastomere ...................................................................................................................... 45
15.7 Steuerleitung ........................................................................................................................................ 45
15.8 Absicherung Ihres Systems ................................................................................................................. 45
15.9 Schutz des Druckminderventils............................................................................................................ 45
15.10 Absperrung........................................................................................................................................... 46
15.11 Panzerung............................................................................................................................................ 46
15.12 Einbaulage ........................................................................................................................................... 46
15.13 Betrieb mit Dampf ................................................................................................................................ 46
15.14 Inbetriebnahme .................................................................................................................................... 46
15.15 Einstellung des Drucks......................................................................................................................... 46
15.16 Einbauschemata .................................................................................................................................. 47
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Original operating manual
spring-actuated pressure control valves DM
4
DM-4.X.23.1 Issue 16.08.2023 www.mankenberg.com
1 Introduction
This manual is intended to assist users of a Mankenberg valve during installation, operation and maintenance.
Read the manual thoroughly before installing or putting this valve into service.
caution
Failure to follow the following instructions – particularly the cautionary and warning notes –
may lead to hazards and may invalidate the manufacturer's warranty. Mankenberg is at your
service for any assistance and queries. For the addresses, see section Further information
[Page22], technical information is also available at www.mankenberg.com
2 Intended use
A Mankenberg DM pressure-reducing valve is a device that is intended exclusively for automatically
regulating the outlet pressure of the medium (without any additional electrical/pneumatic energy) after it has
been installed in a pipeline system. The force of the outlet pressure acts on a control mechanism (diaphragm,
piston or bellows) and is in balance with the preload of a spring that has to be adjusted by the user to the
required value within the setting range of the valve.
A Mankenberg UV back pressure regulator is a device that is intended exclusively for automatically regulating
the inlet pressure of the medium (without any additional electrical/pneumatic energy) after it has been installed
in a pipeline system. The force of the inlet pressure acts on a control mechanism (diaphragm, piston or bellows)
and is in balance with the preload of a spring that has to be adjusted by the user to the required value within the
setting range of the valve.
A Mankenberg vacuum control valve VV is a modification of the pressure-reducing or back pressure
regulator, built to regulate pressures in the vacuum range. It only regulates the differential pressure to the
atmosphere.
A Mankenberg DV differential pressure control valve is a modification of the pressure reducing valve or back
pressure regulator, built to regulate differential pressures.
A Mankenberg MR flow control valve is a modification of the pressure – reducing or pressure reducing valve,
built to regulate the flow rate.
danger
A pressure-reducing valve / back pressure regulator / differential pressure control valve / flow
control valve / vacuum control valve is not a safety valve. A suitable valve must be present in
the system to limit any excess pressure.
note
Pressure-regulating valves are generally supplied with a slackened spring and have to be
adjusted to the required pressure after being installed. The required pressure measuring
devices must be installed in an adequate distance upstream and downstream of the valve.
They are not included in the supply schedule of Mankenberg.
Mankenberg planning documents are available to give users precise assistance in selecting and designing the
appropriate valve, e.g.:
In the section < DM: Regulating valves for pressure>
<Design of pressure-regulating valves>
<Know-how on pressure-reducing valves / back pressure regulators>
<Type sheet DM... / UV... / VV... / DV... / MR...> with technical data and tables of the setting ranges and the
dimensions.>
In the following sections, the types DM, UV, VV, DV and MR are referred to as "valve" or "pressure control
valves", except for a few sections which apply to only one of the types mentioned.

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danger of
fatalities
These valves are no shut-off elements ensuring a tight closing of the valve. These valves are
no shut-off elements ensuring a tight closing of the valve. In accordance with DIN EN 60534-4
and/or ANSI FCI 70-2 they may feature a leakage rate in closed position in compliance with the
leakage classes II – V:
Leakage class II (metal sealing double seat cone) = 0.5% Kvsvalue
Leakage class III (metallic sealing cone) = 0.1% Kvs value
Leakage class IV (PTFE seal cone) = 0.01% Kvs value
Leakage class V, soft seal cone = 1.8 x 10-5 x Δp x D** [l/h]
Consequently, according to DIN EN ISO 2503 and DIN EN ISO 7291, a safety valve has to be
installed on the control side, which is dimensioned and adjusted in such a way that the lower
one of both pressure indications as mentioned below is relevant as response pressure:
- 1.5 times the maximum set pressure and/or (P out) of the valve (see nameplate), whichever
is the lowest
- PS out (see nameplate)
The actuation pressure of the safety valve should be approx. 40% above the max. set value of
the pressure control valve.
The response pressure of the safety valve should be abt. 40 % above the max. set pressure of
the pressure control valve.
Failure to observe this regulation means danger to life and limb and may cause damage
to the pressure-regulating valve.
caution
Pressure-regulating valves are generally supplied with an open bonnet to facilitate
maintenance.
Valves with a sealed bonnet and leakage line connection can be supplied for toxic or
hazardous media. In this case the user must make sure that a suitable leakage line is installed.
Mankenberg valves are supplied as standard for screw-mounted or flange-mounted pipeline/tank connections –
also for special connections if required.
The upper limit of the permitted operating data for pressure and temperature is permanently marked on each
valve supplied.
Pressure gauge option - The technical data of the pressure gauge (connection size and temperature) must
match those of the valve and the plant.
The valve is not ready for use in the delivered condition because the pressure gauge connection is open and no
pressure gauge is supplied. The technical tightness between pressure gauge connection and pressure gauge is
established by the operator.
Option vacuum-proof design- The valve is vacuum-proof and thus can be exposed to external overpressure
to a limited extent.
Gas bonnet option - The outlet pressure to be controlled generates a force on the diaphragm which is in
balance with the gas load in normal operating conditions.
When the inlet pressure and outlet pressure lines are depressurized, the valve is open. When the outlet
pressure rises above the set point adjusted by the gas spring, the valve closes; when the pressure falls below
the set point, the valve opens.

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3 Applied standards and directives
The indicated product is designed according to the AD 2000 regulations without the data sheets S1 and S2.
4 Marking of the valve
Each valve bears the following markings as a minimum:
For Marking Further information for safe use
Manufacturer Mankenberg See section Further information [Page22] for the
addresses.
Valve design Pressure reducing valve +
type
back pressure regulator +
type
vacuum control valve +
type
differential pressure
control + type
flow control valve + type
Design name as per accompanying Mankenberg data
sheet
Nominal diameter e.g. DN or G and
numerical value
Numerical value for DN in [mm], for G in [inches]
Nominal pressure PN or Class and numerical
value, or PS
Numerical value for PN in [bar], for Class in [lbs/square
inch].
Unless otherwise indicated, all data give the
overpressure above atmospheric.
If two numerical values are given, these apply to the
inlet and outlet pressure.
Pressure range Pressure range and
numerical values
Max. permitted
temp.
Temperature and
numerical value
Temperatures above 50 °C entail a reduced pressure
resistance. This must be considered for the
corresponding material in accordance with the DIN EN
1092 standard.
Body material e.g. CrNiMo steel CrNiMo steel = high-alloy austenitic steel
Flow direction Indicated by an arrow
ATEX protection
class
e.g. Ex II 2G Ex h IIB Only for devices with conformity certification according
to ATEX
The markings (in the case of valves made of deep-drawn stainless steel, they are etched into the body) should
neither be covered nor painted over, so that the valve remains identifiable.

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5 Safety instructions
5.1 General precaution
The same safety regulations apply to a valve as to the system into which it is installed.
These instructions only give those safety recommendations that have to be additionally observed for the valve.
5.2 Special safety instructions for the plant operator
The following requirements for the intended use of a valve are not the responsibility of the manufacturer but
have to be guaranteed by the user:
» The valve may only be employed for the purpose described in section Intended use [Page4] .
» Only competent specialist personnel may install, operate and service the valve. Competent as defined in
these instructions refers to persons who, because of their training, specialist knowledge and professional
experience, are capable of correctly assessing and properly executing the work with which they are
entrusted and of recognizing and rectifying hazards.
» The pipeline system must be properly designed and installed so that the valve can be mounted and
operated without any tension.
» The valve must be properly installed in the correct mounting position.
» The recommended installation, as described in the relevant Mankenberg data sheet, must be used for the
pipeline section into which the pressure-regulating valve is installed. All control and/or leakage lines that are
required on the pressure-regulating valve must be laid properly, in accordance with the accompanying
Mankenberg data sheet.
» A pressure-regulating valve with an open spring must be installed in such a way that it presents no risk of
crushing to the operating personnel.
» The usual flow rates should not be exceeded in the pipeline section during continuous operation, and
abnormal operating conditions such as vibrations, unusually high flow rates, etc. should be avoided or – if
unavoidable – clarified with the manufacturer in advance.
» The prevailing operating conditions must comply with the limits of the design data stated in the Mankenberg
order confirmation.
» The corrosion protection for the valve must be adapted to the local environmental conditions.
» The valve must not be coated with thermal insulation.
Detailed notes are provided on some of these prerequisites in the following sections.
5.3 Special hazards
danger of
fatalities
Before a valve is removed from the system or before a valve is dismantled but partially remains
in place, the pressure in the system on both the inlet and outlet side must be completely
reduced so that there is no uncontrolled flow of the medium out of the system.
In the case of toxic or hazardous media, the system must be completely drained before the
valve is removed.
Caution is required with residues that might continue flowing.

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danger of
being
crushed
Only valves with open spring:
It is necessary to ensure on site, by an appropriate installation or by providing safety devices
and/or positioning a clearly visible warning sign in accordance with the regulations of EN 292
(formerly accident prevention regulations), that effective protection is afforded against
objects catching on an exposed spring in the pressure-regulating valve.
If required, Mankenberg will assist in selecting a suitable type with closed bonnet.
danger of
fatalities
If a pressure-regulating valve has to be dismantled:
The following must be observed at all costs: First release the tension fully on the spring by
turning the setting screw on the spring module anticlockwise. When doing so, be sure to
follow the notes in section Initial start-up [Page14]!
Then either seal off the two shut-off valves installed upstream and downstream of the valve in
accordance with the Mankenberg installation recommendation and vent the pressure-
regulating valve, or remove the pressure from the section of the system and then remove the
valve from the pipeline.
caution
If a valve is removed from a system with a toxic medium and is taken out of the plant:
it must be properly decontaminated before repair.
note
Possible malfunction due to external influences
External influences, e.g. pressure on the vent hole, can cause control deviations or damage
internal parts.
When cleaning the outer surface, do not hold the high-pressure steam cleaner or compressed
air blow-off gun near the vent hole.
note
Malfunction due to clogging of the vent hole
External influences, e.g. covering, clogging or sticking of the vent hole, may interfere the
control behavior of the valve. The valve no longer controls reliably.
The vent hole must be kept free!
6 Transport and storage
A valve must be handled, transported and stored with care:
» The valve must be transported and stored in its protective packaging until it is installed.
caution
The valve has moving internal parts.
Even packed valves should be transported smoothly without any shocks.
caution
In the case of a valve that can no longer be transported by hand, the lifting gear must be
attached to a suitable position on the housing (branches).
Under no circumstances may the lifting gear be affixed to any attachments (adjusting
screw, handwheel or accessories).

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» When stored before installation, the valve must be stored in closed spaces and protected from harmful
influences such as dirt, moisture and frost.
» In special cases, the valve is supplied free of oil, grease or silicone and is marked accordingly. During
storage and handling (especially during subsequent unpacking), such a valve must not come into contact
with oil/grease/silicone.
» A Mankenberg valve usually has functional and/or sealing parts made of elastomer materials. These cannot
be stored for an unlimited period.
note
ISO 2023 describes storage conditions for elastomers in detail and specifies the permissible
storage period.
Functional and sealing parts must be replaced in good time before the end of the
storage period. They are available from Mankenberg as a "maintenance kit". See section
Troubleshooting help [Page19].
note
Mankenberg valves of small and medium nominal sizes are mainly made of stainless steel
(high-alloy CrNiMo steel).
These valves – if, under exceptional circumstances, they are stored unpacked – must be
protected from ferritic dust to avoid corrosion.
note
The valve is generally not capable of standing alone:
The spring module may have a greater weight/volume than the basic body with its pipe
connections.
Handle with care so that the valve does not tip over during transport/storage.
» Pressure-regulating valves are generally supplied with a slackened spring. The spring must not be
pretensioned by means of the adjusting screw until after it has been installed, during initial start-up.
7 Installation
7.1 General notes
The same installation regulations apply to a valve as to the system into which it is installed. The following
additional notes apply:
» Section Transport and storage [Page8] should also be observed during transport to the installation site.
» The installation location for the proper function of the valve should be a pipe section without flow
disturbances, without elbows and without throttling points/shut-off devices close upstream and downstream
of the valve (optimum distance = 10 x DN). If this does not apply, the installation situation must be agreed
with the operator and/or Mankenberg.
» The statics of the pipeline must match the weight of the device, especially of those with off-centered mass. If
required the pipeline may have to be properly supported on both sides next to the valve (or at the valve
itself) – particularly in the case of valves with a substantial mass and especially if vibrations are to be
expected in the system. When the valve is supported, it is important to check that all functioning parts
(adjusting screws, springs) remain capable of moving freely and are not blocked.
» The valve must not be wrapped in thermal insulation.

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caution
A valve that is operated at a medium temperature above 130°C needs undisrupted removal of
heat if it is to function perfectly.
Failure to observe this instruction may cause damage to the valves and hence in the
pipeline system as well.
» To protect internal functional parts (e.g. the seat) against damage and/or blockages, it may be necessary to
install a strainer and/or filter upstream of the valve.
note
The mesh size of the sieve/filter for protecting against particles in the pipe section should be
selected by the plant operator according to the operating conditions.
Failure to observe this instruction may cause damage to the valve and hence in the
pipeline system as well.
7.2 Installation preparations
» It must be ensured that a valve is only installed if its function, pressure and temperature range, body
material, body material, connection type and dimensions correspond to the operating conditions.
danger of
fatalities
No valve may be operated that does not have a sufficient pressure and temperature range for
the operating conditions – see section Intended use [Page4] and markings on the valve. The
manufacturer Mankenberg should be consulted in the case of any applications outside of this
range.
Failure to observe this regulation may mean danger to life and limb and may cause
damage to the pipeline system.
» Newly installed containers or line sections must be carefully rinsed and cleaned before the valve is
commissioned.
» The corrosion protection of the valve must be adapted to the conditions on site.
» A pressure-regulating valve with an exposed spring must be installed in such a way that it presents no risk
of crushing to the operating personnel.
danger of
being
crushed
Only valves with open spring:
It is necessary to ensure on site, by an appropriate installation (e.g. not freely accessible) or
providing safety devices and/or positioning a clearly visible warning sign in accordance with the
regulations of EN 292 (formerly accident prevention regulations), that effective protection is
afforded against objects catching on an exposed spring in the pressure-regulating valve.
If required, Mankenberg will assist in selecting a suitable type with closed bonnet.
Failure to observe this instruction: danger of crushing for the operating personnel
» Before installing a pressure-regulating valve, it is necessary to make sure that the pipeline section complies
with the recommended installation, as described in the relevant Mankenberg data sheet. In particular, a
safety valve and a suitable strainer should be installed upstream of the valve.
» Pressure-regulating valves are supplied with a slackened spring:
– in this state of delivery, a pressure reducing valve DM is fully opened and immediately shuts at minimum
outlet pressure.

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– in this state of delivery, a back pressure regulator UV is fully closed and immediately opens at minimum
inlet pressure.
– in this state of delivery, a differential pressure control valve, a flow control valve or a vacuum control
valve responds as a pressure reducing valve or back pressure regulator, according to design.
danger of
fatalities
In the case of toxic or hazardous media, a leakage line must be installed, that discharges
leaking medium safely and pressureless in case of a damaged control device, thus avoiding
dangerous situations.
The diameter should match the connection of the leakage line at the bonnet.
note
In some model series, a control line has to be laid between the pressure-regulating valve and
the pipeline by the customer – this is described in the above-mentioned recommended
installation.
Please note: Only use control lines made of metal, not of plastic!
- distance of valve/connection of control line to the pipeline ≥ 10x pipe-ø
- when the medium is steam, lay the control line at an angle, with the gradient falling towards
the valve, see (catalogue) section Know How Pressure-reducing valves
- The control line should match to the connection on the valve.
- if required, install a throttle to avoid vibration.
» The pressure-regulating valve should first be adjusted during the initial start-up by setting the adjusting
screw on the spring module to the operating conditions – see section Initial start-up [Page14].
However, it is necessary to ensure before installation that there is sufficient room for the appropriate socket or
open-jawed spanner above/below the adjusting screw.
important
note
As a general rule, pressure-regulating valves should be installed in horizontal lines in so
that the spring module (with open spring or with bonnet) points vertically down.
Only for gaseous media installation with the spring pointing vertically up is permissible.
In case the valve must be emptied completely during operation (angle valves), it must be
installed with the bonnet pointing upwards.
If the valve must be installed in a vertical or diagonal line, increased friction of the functional
parts leading to increased abrasion and impaired regulation are to be expected.
7.3 Installation steps
» Valves should only be finally unpacked at the installation site and inspected for damage prior to assembly.
Damaged valves must not be installed.
» Ensure that the covers on all valve ports have been removed before installation.
» The valve should be inspected to ensure that it is clean. Interior parts must be free of liquid (e.g.
condensate): if necessary, connecting branches should be cleaned before installation with clean
compressed air.

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» The type and dimensions of the line or tank connections must match the valve to be installed and be flush
with the connecting surfaces of the valve as well as in a parallel plane to the valve itself.
» The valve is marked with an arrow on the body, the flow in the pipe section must match the marked direction
of flow.
caution
If installed against the direction of the arrow, the valve will not perform its intended function.
» The valve must be installed without any tension. In the case of an already installed system, the geometry of
the pipeline must match the face-to-face length of the valve.
note
It is necessary to ensure that even under operating conditions no tension from the pipeline
is transferred to the valve.
note
A Mankenberg valve is made of "high grade" or "high grade pure" stainless steel (austenite,
e.g. 1.4404 or 1.4435) does not need any surface protection for normal environmental
atmosphere and for normal weather conditions.
External parts of the valve made of low-alloy or non-alloy materials that are supplied ex-works
with a primer have to be provided with a suitable coating by the customer.
Never paint over the marking(s) of the valve (either etched into the body or on
nameplate).
In addition, the following applies to the pipeline connection:
with flanges:
note
The sealing surfaces on the body of the valve are formed in accordance with the Mankenberg
order confirmation. The accompanying flange seals are generally not included in the
Mankenberg supply schedule.
» During installation, centre the valve by means of the flange screws on the mating flange before the screws
are tightened.
with screw-mountings:
note
The connecting surfaces on the body of the valve are formed in accordance with the
Mankenberg order confirmation. The required seals are generally not included in the
Mankenberg supply schedule.

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with welding ends:
» It must be ensured by professional welding that no appreciable stresses are transmitted either to the
pipeline section or to the body of the valve.
» The valve body must never exceed the temperature marked there; otherwise the sealing and functional
parts will be damaged and the entire valve will become unusable.
caution
When a valve with a body made of "high grade" or "high grade pure" deep-drawn parts (visible
on the body connection with clamp rings) is welded, the welding joint must be carried out with
special care; it is recommended that the body should be kept cool with a damp cloth.
Failure to observe these instructions may result in warpage of the valve body: even 0.1 mm of
permanent distortion in the seat region may render the valve unserviceable.
» If available, connect control and/or leakage line.
note
If the leakage line is not connected, the medium will be leaking in the event of damage.
The non-fitted leakage line connection must not be closed under any circumstances. This may
result in improper control behavior of the valve.
Keep the leakage line connection free from external influences such as water, dirt or insects.
8 Pressure testing the pipeline section
The valve has already been pressure-tested by the manufacturer. The following points should be observed
when conducting a pressure test on a pipeline section with a pressure-regulating valve installed:
»Pressure reducing valve: the test pressure must not exceed 1.5 times the maximum adjustable outlet
pressure. e.g. a setting range of 4 to 8 bar gives a max. permitted test pressure of 8 bar x 1.5 = 12 bar. The
test pressure on the inlet pressure side is determined by the pressure marked on the body, in addition, the
permitted reducing rate has to be observed (see order confirmation).
»Back pressure regulator the test pressure must not exceed 1.5 times the max. adjustable inlet pressure,
e.g. a setting range of 4 to 8 bar gives a max. permitted test pressure of 8 bar x 1.5 = 12 bar.
»Vacuum control valve: the test pressure must not exceed 1.5 times the max. adjustable pressure. The
information described above should be observed according to whether a pressure-reducing valve or
back pressure regulator forms the basis for the vacuum control valve.
»Differential pressure control valve: the test pressure must not exceed 1.5 times the max. adjustable
pressure. The information described above should be observed according to whether a pressure-reducing
or back pressure valve forms the basis for the differential pressure control valve.
»Flow control valve: the test pressure must not exceed 1.5 times the max. adjustable pressure. The
information described above should be observed according to whether a pressure-reducing valve or
back pressure regulator forms the basis for the flow control valve.
»Under no circumstances may the test pressure exceed 1.5 times the value indicated on the body
with “PN” or “Class”.
If any leakage occurs on the valve, section Troubleshooting help [Page19] should be observed.
note
If the pipe section is flushed and/or dried after assembly or pressure testing, it is necessary to
make sure that the valve has not been damaged by corrosion or excessively high temperature.

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9 Initial start-up
danger of
fatalities
No valve may be operated that does not have a sufficient pressure and temperature range for
the operating conditions – see section Intended use [Page4] and markings on the valve. The
manufacturer Mankenberg should be consulted in the case of any applications outside of this
range.
Failure to observe this regulation may mean danger to life and limb and may cause
damage to the pipeline system.
The valve is supplied with no tension on the spring – hence no defined operating pressure has been set in the
factory. During initial start-up, the valve must be adjusted to the system parameters.
The adjusting screw on the spring module should be tensioned for this purpose: Clockwise rotation (when
looking onto the adjusting screw) has the following effect:
» on the pressure reducing valve: the outlet pressure increases.
» on the back pressure regulator: the inlet pressure increases.
» on the vacuum control valve: the set pressure increases
» on the differential pressure control valve: the operating pressure increases
» on the flow control valve: the flow increases
Annotation to the vacuum control valve:
a vacuum control valve based on a pressure-reducing valve closes at increasing vacuum (differential pressure
to the atmosphere)
A vacuum control valve based on a back pressure regulator opens when the vacuum increases (differential
pressure to the atmosphere).
Annotation to the differential pressure control valve:
a differential pressure control valve based on a pressure-reducing valve closes at increasing differential
pressure
a differential pressure control valve based on a back pressure regulator opens at increasing differential pressure
Annotation to the flow control valve:
a flow control valve based on a pressure-reducing valve closes at increasing flow rate
a flow control valve based on a back pressure regulator opens at increasing flow rate
The target value to be set by means of the adjusting screw shall be defined by the operator of the system and
must be calibrated with the aid of a pressure gauge on the plant side (or some other pressure monitoring
device).
Note on the valve with gas bonnet
After commissioning the outlet pressure to be controlled must be set by means of the constant pressure
reducing valve/effective pressure transmitter.
caution
When looking onto the adjusting screw:
Never fully remove the adjusting screw (by rotating it anticlockwise). Do not block the
adjusting screw in the position of maximum tension (when rotating it clockwise).

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danger
At the beginning of or shortly after the initial start-up, the sieve or the filter insert of any
installed strainer/filter should be cleaned in order to avoid blocking the strainer/filter.
caution
After the initial start-up:
Check the seals on screw-mounted parts of the body and reseal if necessary. Ask Mankenberg
for tightening torque, if necessary.
Observe the relevant notes in section Troubleshooting help [Page19].
caution
After the initial start-up:
Control the leakage line for leaking medium. Observe the relevant notes in section
Troubleshooting help [Page19] .

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10 Normal operation
A properly designed and correctly adjusted pressure control valve works automatically within its pressure control
range and does not need any form of auxiliary energy.
note
To obtain optimum regulating accuracy, the desired operating pressure should be in the upper
part of the setting range of the pressure-regulating valve. This is described in detail in the
Mankenberg section "DM" under "Design of pressure control valves".
In case of doubt, contact Mankenberg Service – see section Further information [Page22].
danger of
fatalities
It is necessary to ensure that the selected materials of the parts of the valve in contact with
media are suitable for the media used. The manufacturer accepts no liability for damage
caused by corrosion due to aggressive media on parts made of unsuitable material.
Failure to observe this instruction may cause severe or fatal injury or damage to the
interior of the piping system and valve.
caution
The valve has functional parts that must maintain their ease of movement. Make sure that both
the external springs and inner parts in contact with the medium cannot freeze nor become
blocked by dirt. Comply with the maintenance intervals.
Failure to observe this instruction may cause damage to the pipeline system and to the
valve.
danger
In some series a control line is laid between the pressure-regulating valve and the pipeline –
see section General notes [Page9].
Damage to this control line may result in danger to life and limb and may impair the
function of the pressure-regulating valve or even lead to complete failure.
note
Pressure-regulating valves are designed for the operating point in accordance with the order.
This operating point may occasionally be changed by the customer by means of the adjusting
screw. However, the setting of the adjusting screw must not be permanently altered (e.g. by
adding a motorized actuator).
Failure to observe this instruction may cause damage to the pressure-regulating valve.
It is recommended that the valve should be inspected to ensure that it is functioning correctly after each new
start-up.

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11 Maintenance
It is recommended that the valve should be inspected to ensure that it is functioning correctly after each new
start-up. It is important that maintenance work is planned and carried out at periodic intervals.
The maintenance plan is a recommendation of the manufacturer Mankenberg, which is to be supplemented as it
has proven itself with the user, and continues to do so, under the operating conditions.
Mankenberg shall assume no liability resulting from improper maintenance and/or repairs.
Sample plan for maintenance work
Kind of maintenance Work to be performed Period 1)
Check function Check whether function is fulfilled as per section Intended
use [Page4]
at least 1x per
week
Function / check free
movement of the
spindle
With a non-rising adjusting screw (without counternut),
cone movement in the valve seat can be detected by
checking the movement of the adjusting screw.
at least 2x per year
Check seal on the
body, the pipe
connection and the
control lines
Visual check at least 1x per
month
Grease sliding points Grease external sliding points with a corrosion-protection
lubricant
at least 4x per year
Monitor exposed
spring
Visual inspection If necessary, remove any dirt/corrosion 2) at least 2x per year
If installed upstream of
the valve:
clean strainer
According to the manufacturer's instructions depends on the
contamination of
the medium
Preventive
maintenance Dismantle valve, see section Troubleshooting help
[Page19].
Visual inspection of diaphragm and functional parts
Replace all parts of the maintenance set 3)
at least 1x per year
Check the safety valve According to the manufacturer's instructions at least 1x per year
1) See comment at the beginning of this section: These time intervals are guideline values, these must be
adjusted depending on the prevailing operating conditions, the properties of the medium in the system and
the experiences of the user.
2) Caution danger of crushing: shut down the valve for cleaning purposes!
3) Request maintenance kit and replacement instructions from Mankenberg

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danger
During maintenance work (except for visual inspections), observe the respective notes and
warning notices in the section Troubleshooting help [Page19]
Failure to observe this warning may mean danger to life and limb and may cause
damage to the pipeline system and to the valve.
When a valve that has previously been dismantled is being put back into service, the valve should be checked
for proper sealing capacity and function as well as correct adjustment of the adjusting and functional
components!
Gas bonnet option
For maintenance of the gas bonnet proceed as follows:
1. Depressurize the valve and dismount it.
NOTICE!If the valve is not removed, the loosened cone stem may fall into the inlet piping!
2. Remove gas bonnet and check mobility of the control parts.
3. Remove pinched areas with fine emery cloth.
4. Check diaphragm for leakage or damage. This would be indicated by fluid entering the bonnet.
Replace diaphragm, for this purpose:
» loosen stem nut at the diaphragm
» pull out diaphragm disc and remove diaphragm with O-ring
» insert new diaphragm and O-ring
Tighten firmly the stem nut and the screws at the clamp.
Tighten the screws at the bonnet only slightly, otherwise the diaphragm will be crushed.
NOTICE!Lubricants must be adequate. They must not react with the elastomers and the fluid used. To
get a recommendation, contact the service department, see chapter Further information.
Do not oil or grease EPDM.

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12 Troubleshooting help
When troubleshooting, the section Safety instructions [Page7] must be observed.
Spare parts must be ordered with all the information on the type plate.
Only original parts from the manufacturer Mankenberg may be installed.
Mankenberg specialists are available to rectify faults as quickly as possible, for addresses see section Further
information [Page22].
note
If functional or corrosion damage is detected during maintenance or after a fault:
consult Mankenberg to find out whether a more suitable valve is available or whether the
damaged part can be supplied in a better-suited material.
note
Special tools required:
To dismantle the following pressure control valves, a special tool is required (can be requested
at Mankenberg if required):
- pressure reducing valve DM 662
- back pressure regulator UV 5.1 up to and including DN25 / G1“
- and vacuum control valve deducted from these, e.g. VV 5.1
Type of fault Action
Leakage at a
connection body
parts (flange or
clamp ring):
reseal connection
Tighten the screws clockwise (tighten flange screws crosswise).
If the screws of the body connection have to be loosened or removed (= unscrewing
in the anticlockwise direction):
Danger of fatalities
To prevent any risk for operating personnel, make sure that this repair measure is
only carried out on a section of pipe that is not under pressure. Take note of section
Special hazards [Page7] and then section Installation [Page9] .
Leakage on the
bonnet:
the valve must be
repaired
The control mechanism (diaphragm, piston or bellows) is defective and has to be
replaced:
Repair necessary, as described further below.
Danger of fatalities
The pretensioned spring must be fully slackened before a valve is dismantled!
To prevent any risk for operating personnel, make sure that this repair measure is
only carried out when the valve is not under pressure. Take note of section Special
hazards [Page7] .

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Type of fault Action
Malfunction
Leakage at the seat
means the set inlet
or outlet pressure is
not correctly
regulated:
clean the
functional parts
A foreign object may be jammed in the seat and be preventing proper sealing:
- Pressure reducing valve DM: fully tighten spring
- Back pressure regulator UV: fully release the tension of the spring
- Vacuum control valve: according to design, the abovementioned has to be
observed
- Differential pressure control valve: according to design, the abovementioned has to
be observed
- Flow control valve: according to design, the abovementioned has to be observed
so that the valves open and foreign objects can be flushed out.
If the functional fault cannot be rectified in this way: Cleaning is necessary: the
pressure-reducing valve must be dismantled
Danger of fatalities
The pretensioned spring must be fully slackened before a valve is dismantled!
To prevent any risk for operating personnel, make sure that this repair measure is
only carried out when the valve is not under pressure. Take note of section Special
hazards [Page7].
When the valve is not under pressure, take off the spring module by releasing the
clamp rings (or the screw connection) and dismantle the diaphragm (or piston/
bellows) and functional parts for cleaning. Here all parts of the maintenance set
should be renewed.
Afterwards, assemble the valve and readjust it, as described under section Initial
start-up [Page14].
Malfunction
Cleaning alone –
see above – cannot
rectify the fault:
the valve must be
repaired
If during cleaning it is found that the control mechanism (diaphragm, piston or
bellows), the cone or other functional parts are damaged:
Repair necessary: damaged parts must be replaced.
If the repair is to be carried out in the customer's workshop:
make a note of all data according to the markings on the fitting and order the spare
parts and necessary instructions from Mankenberg, see section Further information
[Page22].
or:
Send the valve to the manufacturer for repair. See section Further information
[Page22] for the addresses.