Mankenberg DM 4 Installation instructions

Original operating manual
Pilot-controlled pressure regulators
Originalbetriebsanleitung
pilotgesteuerte Druckregelventile
DM
DM-4.X.222 Stand 18.07.2022 www.mankenberg.com

2
DM-4.X.222 Stand 18.07.2022 www.mankenberg.com
Table of contents EN
1 Introduction................................................................................................................................................. 4
2 Intended use ............................................................................................................................................... 4
3 Marking of the fitting.................................................................................................................................. 6
4 Safety instructions ..................................................................................................................................... 7
4.1 General precaution .............................................................................................................................. 7
4.2 Special safety instructions for the plant operator................................................................................. 7
4.3 Special hazards ................................................................................................................................... 7
5 Transport and storage ............................................................................................................................... 8
6 Installation................................................................................................................................................... 9
6.1 General notes ...................................................................................................................................... 9
6.2 Installation preparations....................................................................................................................... 10
6.3 Installation steps .................................................................................................................................. 11
7 Pressure testing the pipeline section....................................................................................................... 13
8 Initial start-up.............................................................................................................................................. 14
9 Normal operation........................................................................................................................................ 15
10 Maintenance................................................................................................................................................ 16
11 Troubleshooting help................................................................................................................................. 17
12 Information on REACH and RoHS ............................................................................................................ 20
12.1 Declaration on the REACH Regulation 1907/2006.............................................................................. 20
12.2 Declaration on the RoHS Directive 2011/65/EU .................................................................................. 20
13 Further information .................................................................................................................................... 20
14 Know How ................................................................................................................................................... 20
14.1 Tusk ..................................................................................................................................................... 20
14.2 Consideration of the design data ......................................................................................................... 21
14.3 Selecting valve type and nominal diameter ......................................................................................... 21
14.4 Selecting rated pressure and valve material........................................................................................ 21
14.5 Selecting the setting range .................................................................................................................. 21
14.6 Selecting elastomer materials.............................................................................................................. 21
14.7 Sense line (control line) ....................................................................................................................... 21
14.8 Protecting your system ........................................................................................................................ 21
14.9 Protecting the pressure reducing valve ............................................................................................... 21
14.10 Cut-off.................................................................................................................................................. 22
14.11 Stellited seat and cone ........................................................................................................................ 22
14.12 Mounting position................................................................................................................................. 22
14.13 Steam operation .................................................................................................................................. 23
14.14 Start-up................................................................................................................................................ 23
14.15 Setting the pressure............................................................................................................................. 23
14.16 Maintenance ........................................................................................................................................ 24
14.17 ............................................................................................................................................................. 24

Inhaltsverzeichnis DE
1 Einleitung .................................................................................................................................................... 25
2 Bestimmungsgemäße Verwendung.......................................................................................................... 25
3 Kennzeichnung der Armatur ..................................................................................................................... 27
4 Sicherheitshinweise................................................................................................................................... 28
4.1 Allgemeiner Sicherheitshinweis ........................................................................................................... 28
4.2 Spezielle Sicherheitshinweise für den Betreiber.................................................................................. 28
4.3 Besondere Gefahren ........................................................................................................................... 28
5 Transport und Lagerung............................................................................................................................ 29
6 Einbau.......................................................................................................................................................... 30
6.1 Allgemeines ......................................................................................................................................... 30
6.2 Vorbereitung zum Einbau .................................................................................................................... 31
6.3 Schritte beim Einbau............................................................................................................................ 32
7 Druckprüfung des Rohrleitungsabschnitts ............................................................................................. 34
8 Erste Inbetriebnahme................................................................................................................................. 35
9 Normalbetrieb ............................................................................................................................................. 36
10 Wartung....................................................................................................................................................... 37
11 Hilfe bei Störungen..................................................................................................................................... 38
12 REACH- und RoHS-Auskunft .................................................................................................................... 41
12.1 Erklärung zur REACH-Verordnung 1907/2006.................................................................................... 41
12.2 Erklärung zur RoHS-Richtlinie 2011/65/EU ......................................................................................... 41
13 Weitere Informationen................................................................................................................................ 41
14 Know-How................................................................................................................................................... 41
14.1 Funktion ............................................................................................................................................... 41
14.2 Berücksichtigung der Designdaten ...................................................................................................... 42
14.3 Auswahl von Ventiltyp und Nennweite................................................................................................. 42
14.4 Auswahl von Nenndruck und Werkstoff............................................................................................... 42
14.5 Auswahl des Einstellbereichs .............................................................................................................. 42
14.6 Auswahl der Elastomere...................................................................................................................... 42
14.7 Steuerleitung........................................................................................................................................ 42
14.8 Absicherung Ihres Systems ................................................................................................................. 42
14.9 Schutz des Druckminderventils ........................................................................................................... 42
14.10 Absperrung .......................................................................................................................................... 43
14.11 Panzerung ........................................................................................................................................... 43
14.12 Einbaulage........................................................................................................................................... 43
14.13 Betrieb mit Dampf................................................................................................................................ 44
14.14 Inbetriebnahme.................................................................................................................................... 44
14.15 Einstellung des Drucks ........................................................................................................................ 44
14.16 Wartung ............................................................................................................................................... 45
14.17 Einbauschemata.................................................................................................................................. 45
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DM-4.X.222 Stand 18.07.2022 www.mankenberg.com

Original operating manual
Pilot-controlled pressure regulators DM
4
DM-4.X.222 Issue 18.07.2022 www.mankenberg.com
1 Introduction
This manual is intended to assist users of a MANKENBERG pressure-reducing, backpressure regulator,
vacuum control valve, differential pressure control valve or flow control valve during installation, operation and
maintenance. Read the manual thoroughly before installing or putting this valve into service.
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 backpressure 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 VV vacuum control valve is a modification of the pressure-reducing or backpressure
regulator, built to regulate pressures in vacuo. It only regulates the differential pressure to the atmosphere.
A MANKENBERG DV differential pressure control valve is a modification of the pressure reducing or back
pressure regulator, built to regulate differential pressures.
A MANKENBERG MR flow control valve is a modification of the pressure – reducing or backpressure
regulator, built to regulate flow rates.
danger
A pressure-reducing valve / backpressure 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 in front of and behind the fitting.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 fitting, e.g.:
In the section < DM: Regulating valves for pressure>
<Design of pressure-regulating valves>
<Know-how on pressure-reducing valves / backpressure regulators>
<Type sheet DM... / UV... / VV... / DV... / MR...> with technical data and tables of the setting ranges and the
dimensions.>

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danger of
fatalities
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 (metal sealing cone) = 0,1 % Kvsvalue
Leakage class IV (PTFE seal cone) = 0,01 % Kvsvalue
Leakage class V (soft seal cone) = 1,8 x 10-5 x Δp x D* [l/h]
*D=seat diameter
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 response pressure of the safety valve should be abt. 40 % above the max. set pressure of
the pressure control valve.
Contrarily to the Pressure Equipment Directive, Annex 1, Paragraph 7.3, the short-term
maximum excess pressure is limited to 5 % of the max. allowable pressure (see above).
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 connectionv 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
fitting 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 vakuumfeste Ausführung - Die Armatur ist vakuumfest oder und damit begrenzt mit äußerem
Überdruck belastbar

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3 Marking of the fitting
Each fitting bears the following markings as a minimum:
For Marking Remark
Remark MANKENBERG See section Further information [}20] for the address
Fitting design Pressure reducing valve +
type or
backpressure regulator +
type or
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 2 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 IIB TX
-10°C<Ta<+80°C
only for devices with conformity certification according
to ATEX
The markings (in the case of fittings made of deep-drawn stainless steel, they are etched into the body) should
neither be covered nor painted over, so that the fitting remains identifiable.

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4 Safety instructions
4.1 General precaution
The same safety regulations apply to a fitting as to the system into which it is installed. These instructions only
give those safety recommendations that have to be additionally observed for the fitting.
4.2 Special safety instructions for the plant operator
The following requirements for the intended use of a fitting are not the responsibility of the manufacturer but
have to be guaranteed by the user:
» The fitting may only be employed for the purpose described in section Intended use [}4].
» Only competent specialist personnel may install, operate and service the fitting. 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 fitting can be mounted and
operated without any tension.
» The fitting 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 oerating 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 fitting must be adapted to the local environmental conditions.
» The fitting must not be coated with thermal insulation.
Detailed notes are provided on some of these prerequisites in the following sections.
4.3 Special hazards
danger of
fatalities
Before a fitting is removed from the system or before a fitting 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 fitting
is removed.
Caution is required with residues that might continue flowing.
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.

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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. DWhen doing so, be sure to
follow the notes in section Initial start-up [}14]!
Then either seal off the two shut-off valves installed before and after the fitting 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 fitting from the
pipeline.
caution
If a fitting is removed from a system with a toxic medium and is taken out of the plant:
it must be properly decontaminated before repair.
5 Transport and storage
A fitting must be handled, transported and stored with care:
» The fitting must be transported and stored in its protective packaging until it is installed.
caution
The fitting has moving internal parts.
Even packaged fittings should be transported smoothly without any shocks.
caution
In the case of a fitting 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).
» When the fitting is stored prior to installation, it should be kept in closed rooms and protected against
harmful influences such as dirt, moisture and frost.
» In special cases, the fitting is supplied free of oil, grease or silicone and is marked accordingly. A fitting such
as this must not come into contact with oil/grease/silicone during storage and handling (particularly when
subsequently unpacked).
» A MANKENBERG fitting generally has functional and/or sealing parts made of elastomer materials. These
cannot be stored for an unlimited period.
note
ISO 2230 describes the storage conditions for elastomers in detail and specifies the
permissible storage period.
Functional and sealing parts must be replaced well before the storage period expires.
They are available from MANKENBERG as a “service set”. See also Section Troubleshooting
help [}17].
note
MANKENBERG fittings of small and medium nominal diameters are largely made of stainless
steel (high-alloy CrNiMo steel).
If, under exceptional circumstances, fittings are stored in a unpacked state, they must be
protected against ferritic dust to avoid corrosion.

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note
The fitting 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 fitting 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.
6 Installation
6.1 General notes
The same installation regulations apply to a fitting as to the system into which it is installed. The following
additional notes apply:
» Section Transport and storage [}8] should also be observed during transport to the installation site.
» The installation site to allow perfect functioning of a fitting should be a section of pipe without any flow
disruptions, without any angles and without any restrictors or shut-off devices close to the fitting, either
upstream or downstream (optimum distance = 10 x DN). If this does not apply, the installation situation
should be checked with the plant operator and/or MANKENBERG.
» The statics of the pipeline must be designed so as to take account of the weight of the fitting – particularly
those with an eccentric mass. If required, the pipeline may have to be properly supported on both sides next
to the fitting (or at the fitting itself) – particularly in the case of fittings with a substantial mass and especially
if vibrations are to be expected in the system. When the fitting is supported, it is important to check that all
functioning parts (adjusting screws, springs) remain capable of moving freely and are not blocked.
» The fitting must not be coated with thermal insulation.
» The fitting must not be coated with thermal insulation.
caution
A fitting 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 fitting 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 fitting.
note
The mesh size of the sieve/filter for protecting against aggregates in the pipe section should be
selected by the plant operator according to the operating conditions.
Failure to observe this instruction may impair the function of the fitting and lead to
damage.

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6.2 Installation preparations
» It is necessary to ensure that a fitting is not installed unless its matches the operating conditions in terms of
function, pressure and temperature, range, body material as well as connection type and dimensions.
danger of
fatalities
No fitting may be operated that does not have a sufficient pressure and temperature range for
the operating conditions – see section Intended use [}4] and markings on the fitting. 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 pressure-regulating valve.
» Newly installed tanks and pipeline sections must be thoroughly rinsed and cleaned before commissioning
» The corrosion protection for the fitting must be adapted to the local conditions.
» 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 fitting.
» 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.
– in this state of delivery, an backpressure 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 backpressure regulator, according to design.
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 the connection on the fitting.
- if required, install a throttle to avoid vibration.

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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.
» 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 [}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 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.
6.3 Installation steps
» Fittings should only be finally unpacked at the installation site and inspected for damage prior to assembly.
Damaged fittings must not be installed.
» It is necessary to ensure that the covers have been removed from all the connection branches before
installation.
» The fitting 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.
» The type and dimensions of the line or tank connections must match the fitting to be installed and be flush
with the connecting surfaces of the fitting as well as in a parallel plane to the fitting itself.
» If the fitting is marked with an arrow on the housing, the flow in the pipe section must match the marked
direction of flow.
caution
If installed in the opposite direction to the arrow, the fitting will not perform its intended
function.
» The fitting 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 fitting.
note
It is necessary to ensure that even under operating conditions no tension from the pipeline
is transferred to the fitting.

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note
A MANKENBERG fitting 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 fitting 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.
caution:
Never paint over the marking(s) of the fitting (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 fitting 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 fitting 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 fitting are formed in accordance with the
MANKENBERG order confirmation. The required seals are generally not included in the
MANKENBERG supply schedule..
with welding ends:
» Properly performed welding must ensure that no significant tension is transferred to either the section of
pipeline or the body of the fitting.
» Under no circumstances may the body of the fitting exceed the temperature marked on it; otherwise the
sealing and functional parts will be damaged and the whole fitting will become unserviceable.
caution
When a fitting with a body made of "high grade" or "high grade pure" deep-drawn parts (vi-
sible 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 this instruction may cause distortion of the fitting body:
even 0.1 mm of permanent distortion in the seat region may render the fitting unserviceable.

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» 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.
7 Pressure testing the pipeline section
The fitting 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 max. 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).
»Backpressure 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 or
backpressure 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 backpressure regulator 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 or
backpressure 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”.
note
If the pipe section is flushed and/or dried after assembly or pressure testing, it isnecessary to
make sure that the fitting has not been damaged by corrosion or excessively high temperature.
If any leakage occurs on the fitting, section Troubleshooting help [}17] should be observed.

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8 Initial start-up
danger of
fatalities
No fitting may be operated that does not have a sufficient pressure and temperature range for
the operating conditions – see section Intended use [}4] and markings on the fitting. 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 pressure-regulating valve.
The fitting 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 backpressure 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 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 an backpressure 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 an backpressure regulator opens at increasing flow rate
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 backpressure regulator opens at increasing vacuum (differential pressure to
the atmosphere)
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).
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).
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.

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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 [}17].
caution
After the initial start-up:
Control the leakage line for leaking medium. Observe the relevant notes in section
Troubleshooting help [}17].
9 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 “DM”
section of the MANKENBERG catalogue under “Calculation of Pressure Regulators”.
In case of doubt, contact MANKENBERG Service – see section Further information [}20].
danger of
fatalities
It is necessary to ensure that the materials selected for the parts of the fitting in contact with
media are suitable for the media in use. The manufacturer accepts no liability for any damage
due to corrosion by aggressive media on parts made of unsuitable materials.
Failure to observe this regulation may mean danger to life and limb and may cause
damage to the pipeline system and to the fitting.
caution
The fitting has functional parts that have to remain capable of moving easily. Make sure that
both the external springs and inner parts in contact with the medium cannot freeze nor become
blocked by dirt. Observe the maintenance intervals.
Failure to observe this instruction may cause damage to the pipeline system and to the
fitting.
danger
In some series a control line is laid between the pressure-regulating valve and the pipeline –
see Section General notes [}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 fitting should be inspected to ensure that it is functioning correctly after each new
start-up.

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10 Maintenance
The automatic function of the fitting requires maintenance to ensure that it continues to operate perfectly. It is
important for maintenance work to take place in a planned manner at periodic intervals.
The maintenance plan is a recommendation by the manufacturer MANKENBERG, which should be
supplemented by practical experience gained by the user under the prevailing operating conditions.
MANKENBERG shall assume no liability resulting from improper maintenance and/or repairs.
Sample plan for maintenance work
Type of maintenance Work to be performed Period 1)
Check function Check whether function is fulfilled as per section Intended
use [}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 inspection 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 fitting:
clean strainer
According to the manufacturer's instructions Depends on the
contamination of
the medium
Preventive
maintenance Dismantle fitting, see Section Troubleshooting help
[}17].
Visual inspection diaphragm and functional parts
Replace all parts of the maintenance set 3)
at least 1x per year
Check safety valve According to the manufacturer's instructions at least 1x per year
1) See comment at the beginning of this section: The time intervals are guides which should be adapted to
match the prevailing operating conditions, the properties of the medium in the system and the user's
experience.
2) Caution danger of crushing: shut down the valve for cleaning purposes!
3) Request maintenance set and replacement instructions from MANKENBERG.

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danger
During maintenance work (apart from visual inspections) the relevant recommendations and
warning notes in section Troubleshooting help [}17] should be observed.
Failure to observe this warning may mean danger to life and limb and may cause
damage to the pipeline system and to the fitting.
When a fitting that has previously been dismantled is being put back into service, the fitting should be checked
for proper sealing capacity and function as well as correct adjustment of the adjusting and functional
components!
11 Troubleshooting help
When troubleshooting, the section Safety instructions [}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 [}20].
note
If functional or corrosion damage is detected during maintenance or after a fault:
consult MANKENBERG to find out whether a more suitable fitting 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
- backpressure 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 screwsclockwise (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 [}7] and then sectionInstallation [}9].

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Type of fault Action
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 relaxed before a fitting is dismantled!
To prevent any risk for operating personnel, make sure that this repair measure is
only carried out when the fitting is not under pressure. Take note of section Special
hazards [}7].
Functional fault
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
- Backpressure 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: je nach Ausführung o.g. zu beachtenaccording 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
Danger of fatalities The pretensioned spring must be fully relaxed before a
fitting is dismantled!
To prevent any risk for operating personnel, make sure that this repair measure is
only carried out when the fitting is not under pressure. Take note of section Special
hazards [}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 fitting and readjust it, as described under sectionInitial
start-up [}14].

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Type of fault Action
Functional fault
Cleaning alone –
see above – cannot
rectify the fault:
the fitting 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 have to 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 [}20] for addresses.
or:
Send the fitting to the manufacturer for repair. See section Further information
[}20] for addresses.
Unstable operating
behavior
The result can be
increased abrasion,
oscillations and
vibrations.
For valves with KVS reduction, reduce the rate of flow.
For valves without KVS reduction, increase the rate of flow.

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12 Information on REACH and RoHS
12.1 Declaration on the REACH Regulation 1907/2006
Some Mankenberg products contain a candidate substance (SVHC) according to the Candidate List (REACH-
VO, Article 33); as of January 2021.
The following products have components that contain candidate substances (SVHC) in a concentration of more
than 0.1 mass percent:
Product name Name (CAS N°) Components involved Further information for
safe use
Pressure reducing valve
DM 4
Lead (7439-92-1) guide bush, lantern Since lead is a fixed
alloy component and
therefore no exposure is
expected, no additional
information on safe use
is necessary.
Pressure reducing valve
DM 401
Lead (7439-92-1) piston flange
Pressure reducing valve
DM 502
Lead (7439-92-1) seat, cone, disc, piston
guide
Pressure reducing valve
DM 701
Lead (7439-92-1) piston flange, bushing, lower
part
Back pressure regulator
UV 1.2
Lead (7439-92-1) disc, piston guide
Back pressure regulator
UV 1.6
Lead (7439-92-1) lantern
Back pressure regulator
UV 3.2
Lead (7439-92-1) piston guide
12.2 Declaration on the RoHS Directive 2011/65/EU
Mankenberg products are no electrical or electronic equipment and therefore do not fall within the scope of the
RoHS Directive 2011/65/EU (RoHS, Article 4, para. 1 or Annex I).
13 Further information
You can obtain these instructions, the MANKENBERG data sheets quoted as well as further information –
including English language versions – from the following addresses:
Mankenberg GmbH
Spenglerstrasse 99
D-23556 Lübeck
Phone [phone]
Fax [phone]
E-Mail [email protected]
www.mankenberg.de
14 Know How
14.1 Tusk
Pressure reducing valves reduce a high and frequently fluctuating pressure to an adjustable constant pressure
downstream of the valve. A spring keeps the valve open and this closes as the outlet pressure rises