MEDENUS RS 254 Manual

© .201
Gas pressure regulator
RS 254 / RS 255
Operating and Maintenance Instructions

Subject to technical modifications! Reprint prohibited!

© .201
Table of Contents
1 General Information 4
1.1 Warranty and Liability 4
1.2 Symbols, Notes 5
1.3 Terms, Abbreviations 5
2 Safety Instructions 6
2.1 Hazards of Handling the Device 6
2.2 Personnel Requirements 6
2.3 Country-Specific Requirements 6
2.4 Handover of the Operating and Maintenance Instructions 6
2.5 Safety in Operation 7
2.6 What To Do in Case of Danger 7
3 Responsibility of the Operator 7
4 Transport, Storage and Packaging 8
4.1 Transport 8
4.2 Storage 8
4.3 Packaging 8
5 Mounting and Commissioning 9
5.1 Safety Instructions and Preparation 9
5.2 Mounting 10
5.3 Leakage Test (Test for External Leakage) 11
5.4 Initial Commissioning / Recommissioning 12
5.5 Decommissioning 14
6 Maintenance 14
6.1 Maintenance Plan 14
6.2 Maintenance Procedure 15
6.3 Table of Screw Tightening Torques MA16
6.4 Lubricants Table 16
6.5 Screw Retention 16
7 Troubleshooting 17
7.1 Gas Pressure Regulator 17
7.2 Safety Shut-Off Valve 18
8 Replacement and Disposal 19
9 Spare Parts 20
9.1 Spare Parts Drawing RS 254 / RS 255 DN 25 - DN200 20
9.2 Optional Spare Parts Drawing 21
9.3 Parts for Maintenance Work 22
Main diaphragm and O-ring 22
Intermediate Diaphragm 22
Valve plate 22
Valve Plate SSV / Diaphragm SSV 23
O-Ring and Sealing Ring Sets 23
Safety diaphragm 24
10 Notes 25
11 Declaration of Conformity 26

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1 General Information
The personnel entrusted with installation, operation or maintenance of the gas pressure regulator must
have completely read and understood beforehand the following documents:
• Gas Pressure Regulator RS 254 / RS 255 Product Information
The product information contains technical data, dimensions and a description of the design and the mode of
operation.
• Gas Pressure Regulator RS 254 / RS 255 Operating and Maintenance Instructions
This document allows safe and efficient handling of the device and contains information on assembly,
commissioning, maintenance, troubleshooting and repair according to regulations.
It is an integral part of the scope of delivery of the device, must be kept in close proximity of the device and
must be readily accessible to personnel at any time.
The basic requirement of safe operation is compliance with all safety instructions and guidelines specified in
these instructions. Accordingly, the information and instructions must be observed when working on the device
or on the gas line. In addition, the local occupational safety regulations and the general safety regulations for
the application range of the device shall apply.
The figures in these instructions are provided for basic understanding and may differ from the actual design.
The contents in these instructions are protected by copyright. They may be used as part of operating the
device. Any other use and / or reproduction is not permitted without prior authorization by the MEDENUS Gas-
Druckregeltechnik GmbH.
1.1 Warranty and Liability
Claims under warranty or liability for personal injury and material damage are generally void,
if one or several of the following conditions are not observed:
• Work on the device during the warranty period may only be performed in consultation with the manufacturer
• Designated use of the device in accordance with the established conditions of use
• Proper installation, commissioning, operation and maintenance of the device
• Operation of the device with properly installed and functioning safety devices only
• Operating and maintenance instructions of the device or of the system
• Observance of the maintenance instructions
• Properly performed repairs
• Supply lines without defects
• The use of original MEDENUS©spare parts and lubricants listed in these instructions or
• Force majeure
It is generally prohibited
• to perform constructive modifications on the device
• to keep using the device despite the detection of a defect

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1.2 Symbols, Notes
The instructions contain safety instructions marked with symbols to indicate possible consequences in case of non-
observance:
1.3 Terms, Abbreviations
Terms and abbreviations are explained below:
DANGER
Note
NOTICE
This combination of symbol and signal word indicates a potentially hazardous
situation which may result in light injuries, damage to the device, the breakdown
of the system, and material or environmental damage if not avoided.
This combination of symbol and signal word indicates an imminent hazardous
situation, resulting in death or serious injuries if not avoided.
This signal word highlights useful tips, recommendations and information for
efficient and trouble-free operation.
ATC Acceptance test certificate
DN Nominal width
GPR Gas pressure regulator
HDS High-pressure screw spindle
MAScrew tightening torque
pdOutlet pressure
pds Setpoint of the
outlet pressure
MOP Maximum operating pressure
in a system
SSV-Safety shut-off valve
SRV Safety relief valve

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2 Safety Instructions
National accident prevention regulations and the system operator's safety regulations are not superseded by these
operating and maintenance instructions and must be taken into consideration with priority (in Germany, see, among
others, DVGW Code of Practice G 600, G 459/II, G 491 and G 495).
When performing work on the device, the current general and specific safety regulations must be observed.
The application limits of the device with respect to the medium, operating pressure and operating temperature can be
found on the type plate affixed to the device or on the acceptance test certificate.
Using the device under different operating conditions must be agreed upon in consultation with
MEDENUS Gas-Druckregeltechnik GmbH.
The mechanical components of the device do not have any potential ignition sources of their own nor any hot surfaces and
are thus not within the scope of 2014/34/EU (ATEX). The electronic accessories used comply with the ATEX requirements.
2.1 Hazards of Handling the Device
MEDENUS©devices conform with current standards and directives, the recognized technical rules
and the recognized safety rules.
However, improper use can result in hazards to the user or to third parties. This can also result in damage to the device
or to the system.
This is why the device may only be used:
• in accordance with its designated use
• in perfect condition
• while observing the notes given in these operating and maintenance instructions, and inspection and
maintenance regulations, which apply to the functioning and safety of the overall system.
Malfunctions or faults must be eliminated immediately.
2.2 Personnel Requirements
The device may only be mounted by qualified personnel.
Only authorised personnel in possession of the required qualification is allowed to perform settings or repairs on the
device.
2.3 Country-Specific Requirements
The rules and regulations applicable at the place of use with respect to
• gas lines, installation of the gas system,
• gas supply,
• work on the gas system,
• accident prevention must be observed and complied with.
2.4 Handover of the Operating and Maintenance Instructions
The supplier of the system shall hand over these operating and maintenance instructions to the operator of the system
no later than during commissioning and training
of the operating personnel with the reminder to carefully store these instructions.

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2.5 Safety in Operation
The device may only be used when all protective devices on the device or in the system are fully functional.
The device must be inspected by a representative of the manufacturer or by a qualified person for externally visible
damage and for proper functioning at least once a year.
A more frequent inspection may become necessary, depending on the system conditions.
2.6 What To Do in Case of Danger
Information on what is to be done in case of danger and in case of accidents can be found in the respective operator's or
specialist companies' work instructions.
3 Responsibility of the Operator
Operator An operator is a person who operates the device himself for commercial or economic purposes or hands
it over to a third party for use / application and is legally responsible for the safety of the user, personnel
or third parties.
The device is used in the industrial sector. Accordingly, the operator of the device is subject to the legal
obligations concerning occupational safety. In addition to the safety instructions contained in these
instructions, the established maintenance intervals must be observed, taking into account the respective
national standard (alarm and hazard prevention plan).
In particular, the following applies:
• The operator is obliged to perform work on MEDENUS©devices during the warranty period only
after consultation with the manufacturer. Otherwise the claims under warranty will become
void.
• The operator must obtain information on the current occupational safety regulations and
determine additional hazards resulting from the special work conditions at the place of use of
the device in a risk assessment. The operator must implement them in the form of operating
manuals for operating the device.
• During the entire time of use of the device, the operator must check whether the operating
manuals drawn up by him conform to the current state of the regulations and, if necessary,
adapt them.
• The operator must clearly regulate and define the responsibilities for installation, operation,
troubleshooting, maintenance and cleaning.
• The operator must ensure that all persons handling the device have read and understood these
instructions. In addition to that, he must train the personnel at regular intervals and inform it
about the dangers.
• The operator must make available to the personnel the required protective equipment and
oblige them to wear the required protective equipment.
• Moreover, the operator is responsible for the device always being in technically perfect condition.
Therefore, the following applies:
• The operator must make sure that the maintenance intervals described in these instructions
are observed.
• The operator must have all safety devices checked regularly for functioning and completeness.
Operator's
obligations

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4 Transport, Storage and Packaging
4.1 Transport
The device is delivered with flange protective caps. They must be removed prior to installation.
Make sure that the device is transported horizontally using suitable lifting gear. The device must be
handled carefully and secured against impact and shock.
In case of transport damage, we will require the following information from the type plate affixed to
the device:
• Type of device
• Device model
• Year of construction / fabrication number
Note
4.2 Storage
Equipment and spare parts must be stored under the following conditions:
• Do not store outdoors.
• Store in a dry and dust-free location.
• Store on a flat surface.
• Do not expose to aggressive media.
• Do not expose to ozone or ionising radiation.
• Do not store adjacent to direct heat sources.
• Avoid mechanical vibrations.
• Storage temperature: 0 to 25°C.
• Relative humidity: < 55 %.
Spare parts:
• Components susceptible to corrosion must be provided with a suitable preservative.
• Do not store O-rings and seals for more than 7 years even if stored properly.
• Spare parts must be stored in their original packaging until use.
Storage period for devices:
• Storage of the device for up to one year:
Store the gas pressure regulator in its original packaging and original condition at the time of supply. All
protective caps of the device must remain mounted.
• Storage of the device for more than 1 year (e.g. as a spare device):
Store the device in its original packaging and original condition at the time of supply and check it for damage
once a year. Check the housing surface for dirt, damage and corrosion. If necessary, clean all external parts.
After 7 years, all O-rings and seals must be replaced.
4.3 Packaging
• The individual packaged items have been packaged in view of the transport conditions to be expected.
• The symbols on the packaging must be observed during transport and storage.
• Only environmentally-friendly materials have been used for packaging.
• The packaging is designed for protecting the individual components from transport damage, corrosion and
other damage until mounting. This is why the packaging must not be destroyed and only be removed just prior
to mounting.

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5 Mounting and Commissioning
5.1 Safety Instructions and Preparation
Prior to starting work on pressurised components:
• Close all connections to the gas line.
• Depressurise all pressurised components. Also discharge residual energies.
• Defective components that are subject to pressure in operation must be replaced
immediately by a suitable qualified person.
Prior to starting work, ensure sufficient clearance for mounting.
Before installing the device, check whether the performance data (type plate) and the scope of
delivery coincide with the order or the system data, i.e., make sure that the provided devices are
suitable for their intended purpose. In particular, the inlet pressure of the system must be lower than
the maximum allowable pressure of the device.
A direct contact of gas valves and fittings, i.e., the control system, with hardening masonry, concrete
walls or floors is not allowed. Provide suitable supports, working materials and protective equipment.
Take into account the minimum clearances for maintenance as stated in the product information.
Before installing the device in the pipeline, check whether a shut-off device that interrupts the gas
flow supply to the device has been mounted upstream and downstream of the device to be installed.
Prior to commissioning, make sure that all installation work has been carried out and completed
in accordance with the data and information given in these instructions and that no unauthorised
persons stay in the danger zone.
DANGER
Note
Note
DANGER

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5.01 5.02 5.03
5.06 5.07 5.08
5.04
5.05
5.10
5.11 5.125.09 5.13
5.28
5.2 Mounting
• Remove packaging and protection from the connection flange surfaces.
• Install the device without twisting the pipeline. Tighten screws crosswise.
Make sure to observe the direction of flow, i.e. the arrow on the housing must point in the
direction of flow.
• In all installation positions other than horizontal,
MEDENUS Gas-Druckregeltechnik GmbH must be consulted.
• The tightening torques of the flange connections and additional information is available in
the DVGW GAS information issue no. 19 (Flanged Connections in Gas Installations).
Note
Note
• A separate installation of the SSV breather line (item 5.07) is recommended.
• All breather lines (items 5.04 / 5.07) must be vented to the outside atmosphere.
• Breather lines (items 5.04 / 5.07) may not be required
if breather valves or safety diaphragms are being used.
• The measuring lines (items 5.05 / 5.08) must be connected in a pipeline section with a steady flow. There must
be no installations that cause flow interference such as shutters, expansions, manifolds, junctions, isolation
valves etc. directly upstream and downstream of the measurement point.
• The maximum flow rate at the measuring point must not exceed 25 m/s, depending on the system conditions.
• In certain system circuits, such as gas control systems for gas motors and in gas burners, higher flow rates
than 25 m/s are also possible. Please contact us.
• The measuring line must be connected to the pipeline separately, laterally or at the top for each device (1 gas
pressure regulator (item 5.03); 1 integrated SSV (item 5.06).
• The SSV measuring line (Pos. 5.08) must always be connected to the measuring point in front of the first outlet-
side shut-off valve (item 5.13).
Note
fig. 5.1
measuring
point
measuring
point

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5.10
5.09
5.10
5.09
For Germany:
According to DVGW Code of Practice G 491, the fully assembled system must be subjected to a leakage test with air or
an inert gas at the installation site, using 1.1 times the maximum operating pressure of the system (MOP).
An exception is the room between the actuator installed in the gas pressure regulator and the first shut-off valve on the
outlet side. This room must be checked using the a test pressure corresponding to the maximum permissible pressure
in the system in case of a malfunction (1.1 MOPd). In this test, all detachable connections must be checked using a
foaming agent.
In direct-acting devices (without power supply), the outlet pressure acting on the actuator (limited by
the SSV) should not be more than 0.5 bar above the set setpoint. This should be taken into account
when specifying the response pressure of the upstream SSVs.
Recommended upper response pressures:
• Pd≤100 mbar Pdso = Pd+ 50 mbar
• Pd> 100 - 200 mbar Pdso = Pd+ 100 mbar
• Pd> 200 - 1000 mbar Pdso = Pdx 1.5
• Pd> 1000 mbar Pdso = Pd+ 500 mbar
For other countries:
The relevant national and international standards shall apply.
Procedure
• Close the ball valves upstream of the valves and fittings (item
5.01).
• Close the downstream shut-off devices (item 5.13) (ball valves,
solenoid or pneumatic valve).
• Depressurise the system (item 5.11).
• If there is a SRV (safety relief valve) in the controlled section and
the test pressure is higher than the relief pressure of the SRV (item
5.09), the line upstream of the SRV (item 5.10) must be closed.
• Raise the test pressure always slowly and steadily.
5.3 Leakage Test (Test for External Leakage)
The devices are subjected to a strength and leakage test ex works at MEDENUS Gas-Druckregeltechnik GmbH.
The leakage test in the fully assembled system must be performed prior to commissioning and following maintenance
work.
For the external leakage test in the fully assembled system, the following applies:
While doing so, you must ensure:
Pressure in outlet chamber (item 5.12) ≤Pressure in inlet chamber
(item 5.02)
Pressure build-up always from the inlet side (inlet chamber)
Pressure reduction always from the outlet side (outlet chamber)
• After leakage test:
Open the ball valve in the SRV line (item 5.10) again.
Note
NOTICE
Note
fig. 5.2
fig. 5.2.1

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5.15
5.14
5.17
5.16
5.19
5.18
5.14
5.4 Initial Commissioning / Recommissioning
Initial commissioning of the system components shall be carried out by the operator. For commissioning, please refer
to the documents listed under item 1 "General Information" and the system operator's work instruction.
The devices delivered by MEDENUS Gas-Druckregeltechnik GmbH are factory-set to the operating data specified by
the customer. This data is listed on the Acceptance Test Certificate (ATC)* and the type plate.
Prior to commissioning of the system, a functional test must be performed on the gas pressure
regulator (GPR), if applicable, and the safety shut-off and safety relief valves.
Procedure (fig. 5.1)
• Close the ball valves upstream of the valves and fittings (item 5.01).
• Close the downstream shut-off devices (item 5.13) (ball valves, solenoid or pneumatic valve).
• Depressurise the system (item 5.11).
• Close venting ball valve (item 5.11).
• Slowly open ball valve upstream of the valves and fittings (item 5.01).
If the inlet shut-off device is equipped with a bypass, the latter must be slowly opened for pressure
compensation as step 1. This is followed by slowly opening the inlet shut-off valve. The same is true
of the outlet shut-off valve.
• Check the inner leakage of the SSV (item 5.06) by reading the pressure
gauge installed downstream of the GPR (item 5.12).
• Unscrew the sealing cap (item 5.15) of the safety shut-off valve (SSV).
• Perform pressure compensation via the SSV by pulling at the pull knob (item
5.14) and allowing the SSV to engage. In GPR with bypass ball valve (item
5.28), open the ball valve (item 5.28) while pulling the pull knob (item 5.14)
until the SSV engages to perform pressure compensation.
• A closing pressure corresponding to the set value is established on the GPR.
An SSV with underpressure shut-off can only be engaged if the
pressure at the measuring point exceeds the set value by at least
the re-engagement differential.
• Testing the response pressure of the SSV by slowly increasing or decreasing
the output pressure to response pressure.
• It may be necessary to correct the setpoint values of the response pressures.
This is done by turning the SSV setpoint setting screws (items 5.17 / 5.19) to
the right (pressure increase) or left (pressure decrease) in order to increase/
decrease the setpoint value.
The inner setting screw (item 5.17) sets the underpressure shut-off
level (lower trigger level) and the outer setting screw (item 5.19)
sets the upper trigger level.
• Perform pressure compensation via the SSV again by pulling the pull knob
(item 5.14) and allowing the SSV to engage.
*) Acceptance Test Certificate (ATC) available optionally
Note
Note
Note
Note
fig. 5.3
fig. 5.4

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5.21
M
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5.23
5.22
5.25
5.24
• For the functional test of the GPR, let gas flow via the discharge line (venting)
(item 5.11) to the outside atmosphere and read the set regulating pressure
on the outlet pressure gauge (item 5.12).
• It may be necessary to correct the setpoint of the outlet pressure once again.
This is done by turning the GPR setpoint setting screw (item 5.22) to the
right or left, in order to increase and decrease the setpoint, respectively,
after removal of the GPR sealing cap (item 5.21).
• After closing the discharge line (item 5.11), a constant closing pressure
within the closing pressure class can be read on the outlet pressure gauge
(item 5.12).
• Slowly open the shut-off valve (item 5.13), close the discharge line (item
5.11) and read the set regulating pressure on the outlet pressure gauge
(item 5.12).
• It may be necessary to correct the setpoint of the outlet pressure once again.
• Screw on the sealing cap (item 5.15) of the safety shut-off valve (SSV) again.
• Screw on the GPR sealing cap (item 5.21) again.
Changing the control range
Switching to the control range of a different setpoint spring can be done for the SSV as
well as for the GPR while the device is pressurised.
Gas pressure regulator
• Take off the sealing cap (item 5.21) and unscrew the setting screw (item
5.22).
• Pull out the spring plate (item 5.24) with ball (item 5.23) and spring (item
5.25) and replace the spring with one that fits.
• Screw in the spring plate (item 5.24), the ball (item 5.23) and the setting
screw (item 5.22) again.
• Set the desired setpoint and screw on the sealing cap (item 5.21) again.
Safety shut-off valve
• Remove the sealing cap (item 5.15) and screw off the pull knob (item 5.14)
for changing the spring of the underpressure shut-off device (item 5.16).
• Screw off the corresponding setting screw (items 5.17 / 5.19) for the upper
or lower trigger level.
• Pull out the spring (item 5.16 / 5.18) and replace it with one that fits.
• Screw in the setting screw (item 5.17 / 5.19) again and fasten the pull knob
(item 5.14) on the spindle again.
• Set the desired setpoint and screw on the sealing cap (item 5.15).
The SSV closes if the overpressure setpoint spring (upper trigger level) is removed
from a pressurised system.
Note
fig. 5.5
fig. 5.6
fig. 5.7

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6 Maintenance
6.1 Maintenance Plan
The following sections describe the maintenance work required for optimal and trouble-free operation of the device.
If increased wear is detected during regular inspections, the required maintenance intervals must be shortened in
accordance with the actual wear.
For any questions on maintenance work and intervals, please contact the manufacturer.
The intervals for monitoring and maintenance work are strongly dependent on the operating situation and the
condition of the gas. This is why no fixed intervals can be given. For Germany, it is recommended to observe initially the
maintenance periods according to the data given in DVGW Code of Practice G 495. For each system, this must be followed
by determining the maintenance interval independently on a medium-term basis.
During maintenance work, the components must be cleaned and subjected to a thorough visual inspection. This is also
necessary if irregularities in the operating behaviour have been detected during operation or during functional tests.
Damaged parts and O-rings dismounted during dismantling must be replaced with new ones.
The item numbers mentioned in chapter 6.2 (Maintenance Procedure) correspond to those listed in the
spare parts drawings and spare parts lists.
It is recommended to stock the parts listed in chapter 9.3 for maintenance work.
Interval Maintenance activities Personnel
When required
Replacing O-rings
Qualified person
Replacing diaphragms
Replacing the valve plate
Replacing sealing rings for the connections of the breather lines and
measuring lines
5.5 Decommissioning
For decommissioning, please refer to the documents listed under item 1 "General Information" and the system operator's
work instruction.
Procedure (fig. 5.1)
• Slowly close the outlet shut-off valve (item 5.13) or
• Close the ball valves upstream of the valves and fittings (item 5.01).
• Depressurise the system (item 5.11).
• Close venting ball valve (item 5.11).

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6.2 Maintenance Procedure
The maintenance procedure is described in detail step-by-step in our video tutorial and our pictorial descriptions.
Instructions for our products can be found in the download area of our website. Should you have any problems, please
feel free to contact us directly.
If components have been removed, make sure they are mounted correctly, reinstall all fastening
elements and observe the screw tightening torques.
Prior to recommissioning, observe the following:
• Make sure that all maintenance work has been carried out and completed in accordance
with the data and information given in these instructions.
• Make sure that no unauthorised persons stay in the danger zone.
• Make sure that all covers and safety devices have been installed and are working properly.
For recommissioning, please refer to the relevant manufacturer's documentation of the
gas pressure regulator installed in the system or chapter 1 and 5.4 as well as the work instructions of the system
operator, and the other safety regulations for the system in which the regulator is installed.
To guarantee smooth operation, we recommend always keeping a maintenance set in reserve.
NOTICE
DANGER
Note

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50
51
52
53
54
6.3 Table of Screw Tightening Torques MA
Item no. Exception
RS 254 / 025
RS 254 / 050
RS 254 / 080
RS 254 / 100
RS 255 / 050
RS 254 / 150
RS 254 / 200
RS 255 / 080
RS 255 / 100
50 M8 / 18 Nm M10 / 36 Nm
RE 205 M10 / 36 Nm
51 M8 / 18 Nm M10 / 36 Nm
52 M8 / 18 Nm M10 / 36 Nm
DN 200 M12 / 62 Nm
53 M8 / 18 Nm M10 / 32 Nm
DN 200 M12 / 62 Nm
54 M6 / 8 Nm M8 / 18 Nm
6.4 Lubricants Table
Components (apply a thin layer) Lubricants
All O-rings Syntheso Proba 270
All fastening and locking screws Anti Seize AS 450
Balls Unisilkon TK 44N2
6.5 Screw Retention
Components (apply a thin layer) Adhesive and sealing agent
Stud bolts Loctite-648
fig. 6.1

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7 Troubleshooting
7.1 Gas Pressure Regulator
Description of the error Possible cause Elimination
Closing pressure too
high
No closing pressure
Actuator dirty or damaged Check valve plate (seal) and valve seat for damage
and dirt, replace valve plate, if necessary
Static sealing elements defective Replace O-rings
Clamping of the compensating
diaphragm has come off
Compensating membrane is damaged
or mounted incorrectly.
Check compensating diaphragm for fastening,
damage, and correct fit, replace it, if necessary.
Valve plate has become disconnected
from the valve stem Tighten nut under the valve plate
Unstable outlet
pressure curve
(vibrations, pulsation)
Device is working in the closing
pressure range Check regulator design
Vibration resonance in the control
system
Install restrictor plate in breather line
Install baffle plate in measuring line
Continue closing restrictor in measuring line by
turning clockwise *
Install a harder spring (setpoint spring of the next
higher control range)
Check setting of gas consumption devices
Use of throttle valve RSD (optional accessory)
Control deviation too
large
Unfavourable connection of the
measuring line
Select a measuring point with steady flow, check
measuring point
Sluggishness of the device due to dirt Subject device to maintenance
Main diaphragm or compensating
diaphragm defective or mounted
incorrectly
Check diaphragm and replace if necessary
Wrong regulator size selected
Wrong setpoint spring selected
Wrong control cone selection
Check controller design, setpoint spring / control
cone and replace if necessary
Inlet pressure supply is insufficient
(pressure losses in the supply line too
high)
Increase inlet pressure
Check pipeline cross-section
Check built-in filter
Inadmissible pressure
peak
Dynamic closing
pressure too high
Damping of the device too high
Control system too dynamic
Continue opening restrictor in measuring line by
turning anticlockwise
Remove restrictor plate from breather line
Check breather lines and dimension them larger,
if necessary. Replace breather valve with safety
diaphragm or breather line
Closing speed of downstream shut-off
devices too high Reduce closing speed of shut-off device
Noise
Gas velocity too high Check regulator design
Sluggishness of the device due to dirt
/ wear
Perform maintenance on actuator
If worn-out mechanically, replace it, if necessary
Gas escapes through
breather line
Fastening of the main diaphragm has
come off
Main diaphragm is damaged or has
been mounted incorrectly
Check diaphragm for fastening, damage and correct
fit
Internal leakage gas SRV is set too low
or is not tight
Correct settings of leakage gas SRV
Check O-ring for damage and dirt, replace if
necessary
*) Excessive damping limits the actuation speed.
**) Normal flow noise does not constitute a fault. However, this noise can be reduced by installing a
noise reduction device.
Note

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7.2 Safety Shut-Off Valve
Description of the error Possible cause Elimination
No internal tightness
in closed position
Actuator dirty or damaged Check valve seat and valve plate (seal) for damage
and dirt
Pressure compensation valve (internal
bypass) in the actuator dirty or sealing
elements damaged
Check O-rings in the pressure compensation valve
or at the SSV spindle and replace them, if necessary
SSV cannot be opened No pressure compensation at actuator Pressure compensation by opening the bypass ball
valve (item 5.28)
SSV does not engage
Difference between response pressure
and operating pressure or between
upper and lower response pressure is
too small
Correct response pressure settings consider
required re-engagement differential (see RS 254 /
255 product overview)
Only in case of underpressure
switching: Diaphragm
in the control device defective or
incorrectly installed
Check diaphragm and replace it, if necessary
Pressure at the measuring point too
high or low (only with underpressure
switching)
Lower or increase pressure at measuring point to
operating value (GPR setpoint value)
Sluggishness of the trigger
mechanism due to dirt / wear
Service switching device and replace it, if worn-out
mechanically
Permissible
response pressure
group is exceeded
Irregularities in
response behaviour
Difference between response pressure
and operating pressure or between
upper and lower response pressure is
too small
Correct response pressure settings consider
required re-engagement differential (see RS 254 /
255 product overview) *
Diaphragm in the control device
incorrectly installed Check whether diaphragm is twisted
Sluggishness of the trigger
mechanism due to dirt / wear
Service switching device and replace it, if worn-out
mechanically
Gas escapes through
breather line
Diaphragm clamping has become
loose
Diaphragm is damaged or has been
mounted incorrectly
O-ring sealing (item 35) dirty or
damaged
Check diaphragm for fastening, damage and correct
fit
Check O-ring and replace it, if necessary
*) The pressure differences between GPR, SSV and system SRV must consider the response and
closing pressure groups as well as the re-engagement differentials of the devices in order to avoid
any unintended SRV switching.
Note

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8 Replacement and Disposal
After the device has reached the end of its useful life, it must be dismounted and disposed of in an
environmentally compatible manner.
During dismounting, components that may present a risk of injury by contamination
depending on the medium are removed. Depending on the processed medium, the
components must be properly decontaminated. Components capable
of diffusion (diaphragm, O-ring, etc.) may have to be taken to a special disposal unit,
depending on the medium used. If no return or disposal agreement
has been reached, dismantled components should be recycled:
• Metals should be scrapped
• The remaining components should be disposed of after sorting according to material.
For technical information, please contact our customer service:
MEDENUS Gas-Druckregeltechnik GmbH
Saßmicker Hammer 40
D-57462 Olpe
Phone [phone] / 82788-0
Fax [phone] / 82788-9
In addition, we are always interested in information and experience resulting from the application and
which can be valuable for improving our products.
E-Mail [email protected]
Internet www.medenus.de
NOTICE

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20
10
8
9**
2
6
4
7
25
32
34
36
16
14
11
15
12
17
9*
24
30
9 Spare Parts
9.1 Spare Parts Drawing RS 254 / RS 255 DN 25 - DN200
*) 1x O-ring at RE 160 / 205 / 275 / 385
**) 4x O-ring at RE 320 / 390
8x O-ring at RE 485 fig. 9.1