DP17, DP17E, DP17G, DP17R, DP17Y and DP27G Pilot Operated Pressure Reducing Valves

DP17, DP17E, DP17G, DP17R, DP17Y and DP27G Pilot Operated Pressure Reducing Valves
1000026/16
IM-P100-05
CH Issue 16
DP17, DP17E, DP17G, DP17R, DP17Y and DP27G
Pilot Operated Pressure Reducing Valves
Installation and Maintenance Instructions
1. Safety information
IM-P100-05
Printed in theCH
UK Issue 16
2.
General
product information
3.
Installation
4.
Commissioning
5.
Maintenance
6.
Spare parts
7.
Fault finding
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© Copyright 2010
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IM-P100-05 CH Issue 16
1. Safety information
Safe operation of these products can only be guaranteed if they are properly
installed, commissioned, used and maintained by qualified personnel (see
Section 1.11) in compliance with the operating instructions. General installation
and safety instructions for pipeline and plant construction, as well as the proper
use of tools and safety equipment must also be complied with.
1.1 Intended use
Referring to the Installation and Maintenance Instructions, name-plate and
Technical Information Sheet, check that the product is suitable for the intended
use/application. The products listed below comply with the requirements of the
European Pressure Equipment Directive 97/23/EC and carry the
mark when so
required. The products fall within the following Pressure Equipment Directive
categories:
Product
DP17, DP17E, DP17G,
DN15 - DN40
DP17R, DP17Y and DP27G DN50
Group 2
Gases
SEP
1
i) The products have been specifically designed for use on steam, air and inert
industrial gases which are in Group 2 of the above mentioned Pressure Equipment
Directive. The products’ use on other fluids may be possible but, if this is
contemplated, Spirax Sarco should be contacted to confirm the suitability of
the product for the application being considered.
ii) Check material suitability, pressure and temperature and their maximum and
minimum values. If the maximum operating limits of the product are lower than
those of the system in which it is being fitted, or if malfunction of the product
could result in a dangerous overpressure or overtemperature occurrence,
ensure a safety device is included in the system to prevent such over-limit
situations.
iii) Determine the correct installation situation and direction of fluid flow.
iv) Spirax Sarco products are not intended to withstand external stresses that
may be induced by any system to which they are fitted. It is the responsibility of
the installer to consider these stresses and take adequate precautions to
minimise them.
v) Remove protection covers from all connections and protective film from all
name-plates, where appropriate, before installation on steam or other high
temperature applications.
1.2 Access
Ensure safe access and if necessary a safe working platform (suitably guarded)
before attempting to work on the product. Arrange suitable lifting gear if required.
1.3 Lighting
Ensure adequate lighting, particularly where detailed or intricate work is required.
IM-P100-05 CH Issue 16
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1.4 Hazardous liquids or gases in the pipeline
Consider what is in the pipeline or what may have been in the pipeline at some
previous time. Consider: flammable materials, substances hazardous to health,
extremes of temperature.
1.5 Hazardous environment around the product
Consider: explosion risk areas, lack of oxygen (e.g. tanks, pits), dangerous gases,
extremes of temperature, hot surfaces, fire hazard (e.g. during welding), excessive
noise, moving machinery.
1.6 The system
Consider the effect on the complete system of the work proposed. Will any proposed
action (e.g. closing isolation valves, electrical isolation) put any other part of the
system or any personnel at risk?
Dangers might include isolation of vents or protective devices or the rendering
ineffective of controls or alarms. Ensure isolation valves are turned on and off in a
gradual way to avoid system shocks.
1.7 Pressure systems
Ensure that any pressure is isolated and safely vented to atmospheric pressure.
Consider double isolation (double block and bleed) and the locking or labelling of
closed valves. Do not assume that the system has depressurised even when the
pressure gauge indicates zero.
1.8 Temperature
Allow time for temperature to normalise after isolation to avoid danger of burns.
1.9 Tools and consumables
Before starting work ensure that you have suitable tools and/or consumables
available. Use only genuine Spirax Sarco replacement parts.
1.10 Protective clothing
Consider whether you and/or others in the vicinity require any protective clothing
to protect against the hazards of, for example, chemicals, high/low temperature,
radiation, noise, falling objects, and dangers to eyes and face.
1.11 Permits to work
All work must be carried out or be supervised by a suitably competent person.
Installation and operating personnel should be trained in the correct use of the
product according to the Installation and Maintenance Instructions.
Where a formal 'permit to work' system is in force it must be complied with. Where
there is no such system, it is recommended that a responsible person should know
what work is going on and, where necessary, arrange to have an assistant whose
primary responsibility is safety.
Post 'warning notices' if necessary.
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IM-P100-05 CH Issue 16
1.12 Handling
Manual handling of large and/or heavy products may present a risk of injury. Lifting,
pushing, pulling, carrying or supporting a load by bodily force can cause injury
particularly to the back. You are advised to assess the risks taking into account the
task, the individual, the load and the working environment and use the appropriate
handling method depending on the circumstances of the work being done.
1.13 Residual hazards
In normal use the external surface of the product may be very hot. If used at the
maximum permitted operating conditions the surface temperature of some products
may reach temperatures of 300°C (572°F).
Many products are not self-draining. Take due care when dismantling or removing
the product from an installation (refer to 'Maintenance instructions').
1.14 Freezing
Provision must be made to protect products which are not self-draining against
frost damage in environments where they may be exposed to temperatures below
freezing point.
1.15 Disposal
Unless otherwise stated in the Installation and Maintenance Instructions, this
product is recyclable and no ecological hazard is anticipated with its disposal
providing due care is taken. However, if the valve has any PTFE components,
special care must be taken to avoid potential health hazards associated with
decomposition/burning of this material.
PTFE:
- Can only be disposed of by approved methods, not inceration.
- Keep PTFE waste in a separate container, do not mix it with other rubbish, and
consign it to a landfill site.
1.16 Returning products
Customers and stockists are reminded that under EC Health, Safet y and
Environment Law, when returning products to Spirax Sarco they must provide
information on any hazards and the precautions to be taken due to contamination
residues or mechanical damage which may present a healt h, safet y or
environmental risk. This information must be provided in writing including Health
and Safety data sheets relating to any substances identified as hazardous or
potentially hazardous.
IM-P100-05 CH Issue 16
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2. General product information
2.1 General description
These instructions apply to the DP17 and most derivatives including the DP17E, DP17G,
DP17R, DP17Y and DP27G.
The instructions primarily relate to the use of the DP17 on steam but can be used as a guide
when the valve is used on compressed air.
For compressed air the DP17G and DP27G are recommended which have a nitrile seal for
both the main valve and pilot valve.
Note: For additional information see the relevant Technical Information Sheets.
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IM-P100-05 CH Issue 16
2.2 Sizes and pipe connections - DP17, DP17G, DP17R, DP17Y and DP27G
DN15LC (not available for type DP17G), DN15, DN20, DN25, DN32, DN40 and DN50.
Screwed BSP (BS 21 parallel) or NPT (DN15 to DN25 only).
Standard flanges:
DN15 - DN50 BS 4504 PN16 and PN25
DN25 - DN50 BS 10 Table H and ANSI 300
DN15 - DN50 JIS 10 , JIS 16 and ANSI 150 Available on request: DN15 - DN20 BS 10 Table F DN15 ANSI 300
2.3 Pressure / temperature limits DP17, DP17G, DP17R, DP17Y and DP27G
A
F
B
D F
Steam
saturation
curve
C
Pressure bar g
E
Temperature °F
Temperature °C
Pressure psi g
The product must not be used in this region.
A-D-E Screwed and flanged BS 4504 PN25, ANSI 300, and BS 10 Table H.
A-B-CFlanged ANSI 150.
F-F The DP17G and DP27G are limited to 120°C.
Note: DP17, DP17G and DP27G have a variable rate conical pressure adjustable spring
fitted providing a downstream pressure range of 0.2 - 17 bar g.
DP17Y has a pressure spring with a range of 0.2 - 3 bar g.
DP17R Maximum downstream reduced pressure 15 bar g. The control pressure signal
to the pilot diaphragm must be approximately 0.7 bar above the required reduced
downstream pressure.
Body design conditions PN25
PMA Maximum allowable pressure @ 120°C (248°F)
25 bar g (362.5 psi g)
TMA Maximum allowable temperature
232°C
(449.5°F)
Minimum allowable temperature
-10°C
(14°F)
PMO Maximum operating pressure for saturated steam service
17 bar g (246.5 psi g)
TMO Maximum operating DP17, DP17Y and DP17R
232°C
(449.5°F)
temperature
DP17G and DP27G
120°C
(248°F)
Minimum operating temperature
0°C (32°F)
Note: For lower operating temperatures consult Spirax Sarco.
PMXMaximum differential pressure is limited to the PMO
Designed for a maximum cold hydraulic test pressure of: 38 bar g (551 psi g)
Note: With internals fitted, test pressure must not exceed: 25 bar g (362.5 psi g)
IM-P100-05 CH Issue 16
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2.4 Sizes and pipe connections - DP17E
DN15LC (not available for type DP17G), DN15, DN20, DN25, DN32, DN40 and DN50.
Screwed BSP (BS 21 parallel) or NPT (DN15 to DN25 only).
Standard flanges:
DN15 - DN50 BS 4504 PN16 and PN25
DN25 - DN50 BS 10 Table H and ANSI 300
DN15 - DN50 JIS 10, JIS 16 and ANSI 150 Available on request: DN15 - DN20 BS 10 Table F DN15 ANSI 300
2.5 Pressure / temperature limits - DP17E
Pressure bar g
Temperature °F
Temperature °C
Pressure psi g
The product must not be used in this region.
The product should not be used in this region as damage to the internals may occur.
Body design conditions PN25
PMA Maximum allowable pressure @ 120°C (248°F)
25 bar g (362.5 psi g)
TMA Maximum allowable temperature
232°C
(449.5°F)
Minimum allowable temperature
-10°C
(14°F)
PMO Maximum operating pressure including saturated steam service 10 bar g
(145 psi g)
TMO Maximum operating temperature
190°C
(248°F)
Minimum operating temperature
0°C (32°F)
Note: For lower operating temperatures consult Spirax Sarco.
PMXMaximum differential pressure is limited to the PMO
Designed for a maximum cold hydraulic test pressure of: 38 bar g (551 psi g)
Note: With internals fitted, test pressure must not exceed: 25 bar g (362.5 psi g)
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IM-P100-05 CH Issue 16
3. Installation
Note: Before actioning any maintenance programme observe
the 'Safety information' in Section 1.
Referring to these Installation and Maintenance Instructions,
name-plate and Technical Information Sheet, check that the product
is suitable for the intended installation.
3.1 Supply
DP17, DP17G and DP27G (Fig. 1)
These are supplied ready for fitting and have a variable rate conical pressure spring suitable
for a downstream pressure of 0.2 - 17 bar (3 - 247 psi).
DP17Y (Fig. 1)
The DP17Y is supplied as the DP17, but has a lower rate pressure adjustment spring for
a downstream pressure range of 0.2 - 3 bar (3 - 44 psi).
Pressure setting adjustment screw
Lock-nut
Pressure adjustment spring
Internal pressure control
pipe assembly
Alternative recommended
downstream pressure
control pipe connection
(refer to Section 3.8, page 12)
Fig. 1 DP17, DP17G and DP17Y
IM-P100-05 CH Issue 16
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DP17E
The DP17E (Fig. 2) is supplied as for the DP17 with a control spring but the maximum pressure
is limited to 10 bar g (145 psi g) due to the addition of the solenoid valve. A solenoid operated
valve is fitted in the pipe between the pilot valve and the main diaphragm chamber and is thus
in series with the normal pilot valve.
The purpose of the solenoid valve is to override the pilot valve thus causing the main valve
to shut-off. It can be controlled by any device capable of interrupting the supply of current
to the solenoid coil.
The solenoid is arranged to open the valve when the coil is energised so that whatever switching
device is used it must be arranged to break the current to close the main valve. In this way
the unit will always 'fail-safe' i.e. will close the main valve in the event of a failure in electrical
supply.
Electrical supply
It is important that the solenoid is connected to the correct voltage. Therefore always check
on the supply details which are stamped on the solenoid valve name-plate before attempting
to connect up.
Electrical connection is by cable plug to DIN 43650. All wiring, connectors, etc. in close
proximity to the valve should be of heat resisting type and comply with local and national
electrical codes.
Earth
The solenoid valve should be adequately earthed.
Solenoid valve
Fig. 2 DP17E
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IM-P100-05 CH Issue 16
DP17R
The DP17R (see Fig. 3) is supplied ready for fitting. Downstream pressure can be adjusted
remotely by a controlled air supply to the pilot diaphragm chamber. The actuating air supply
must be at a pressure approximately 0.7 bar g (10 psi g) above the required downstream
pressure and controlled through a metal bodied self-relieving regulator. A check valve should
be fitted to prevent steam entering the air system, in the unlikely event of a failure of
the pilot diaphragm. Any filter should be fitted with a metal bowl and should preferably be on
the upstream side of the check valve.
The actuating air supply controlled by the regulator should be connected to the union fitting
attached to the air control block as in Fig. 4. The air inlet connection is suitable for
6 mm O/D copper tube. The maximum reduced pressure available through the DP17R is
15 bar g (218 psi g). Typical installation is shown in Fig. 9, page 15.
Fig. 3 DP17R
IM-P100-05 CH Issue 16
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3.2 Fitting (Figs. 4, 5 and 6)
The valve should always be fitted in a horizontal pipeline with the main diaphragm chamber
below the line (Fig. 4). To meet high capacities or widely varying loads, or where stand-by
facility is required, two or more valves may be used in parallel (Fig. 5). For pressure turndown
in excess of 10 to 1 consideration should be given to using the two valves in series. To avoid
instability pipework volume between the valves should be equivalent to at least 50 pipe
diameters in length of the intermediate correctly sized pipework. To ensure adequate drainage
of the space between the two reducing valves a trap set should be fitted as shown in Fig. 6.
Separator
Strainer with
100 mesh stainless
steel screen
Pressure
control Safety
pipe
valve
Discharge
pipe
Small bore
drain
Pressure
reducing valve
Steam
supply
Spiratec
sensor
chamber
Strainer
Check
valve
0.9 m, (3 ft) or
15 pipe diameters clear
on either side
See Section 3.6, page 11.
Downstream isolating valve to
provide no-load conditions for
setting pressure reducing valve
Float type
steam trap
DP17 and DP17E
Float type
steam trap
Check
valve
Alternative for
draining separator
Strainer
Sight
glass
Separator
Regulator
Filter
Compressed
air
Compressed
air
DP17R
Fig. 4 Recommended installation
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Installation for
compressed air
(DP17G and DP27G)
Compressed
air trap
IM-P100-05 CH Issue 16
]
Steam
supply
]
] See Section 3.6
Fig. 5 Two pressure reducing valves in parallel
3.3 Pipeline sizing
The piping on both sides of the valve must be sized so that velocities do not exceed 30 m/s
(98 ft/s). This means that a properly sized valve will often be smaller than the connecting
pipework.
3.4 Pipeline stresses
Line stresses caused by expansion or inadequate support should not be imposed on the valve
body.
3.5 Isolating valves
These should preferably be of the full bore type.
3.6 Removal of condensate
It is recommended that a separator with trap set is fitted upstream of the valve to ensure dry
steam conditions.
If there is a rise in the low pressure line from the valve then a further drain point should be
provided to keep the valve drained after shutdown.
Steam supply
]
] See Section 3.6
Fig. 6 Two pressure reducing valves installed in series
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3.7 Protection from dirt
The valve should be protected by a pipeline strainer with 100 mesh screen. The strainer
should be fitted on its side to prevent the accumulation of water. The strainer screen should
be examined and cleaned at regular intervals.
3.8 Pressure control pipe
For applications that require closer control, improved stability or maximum capacity condition
the internal pressure control pipe should be replaced by an external pressure control pipe
as follows:
Remove the internal pressure control pipe assembly.
The resulting "BSP tapping in the side of the body should be blanked using the plug
provided in the linen bag attached to the valve (which also contains the fitting instructions).
The other " BSP tapping in the side of the pilot valve chamber, should be blanked off using
the plug fitted in the tapping provided on the front of the pilot valve chamber. Into this latter
tapping, fit the brass compression fitting with brass compression ring which is also contained
in the linen bag. This is suitable for the fitting of 6 mm O/D pipe. If suitable pipe is not
available the compression fitting can be removed and ¼" nominal bore steel pipe screwed
directly into the pilot valve chamber.
The pressure control pipe should be connected into the top of the reduced pressure main
at a point where in either direction there is a length of straight pipe uninterrupted by fittings
for at least 1 m (3 ft) or 15 pipe diameters whichever is the greater. It should be arranged
with a positive fall so that any condensate can drain away from the DP17. Where the size of
the reduced pressure main makes it difficult to maintain a fall when entering the top of the
main, the pressure control pipe may be connected in the side of the main.
3.9 Pressure gauges
It is essential to fit a pressure gauge on the upstream and downstream side so that the
valve can be properly set and monitored.
3.10 Bypass
Information regarding bypasses:
It may be necessary to ensure that primary fluid flow continues in the event of the main
control failing. This is often achieved by fitting a bypass around the control valve assembly.
A better option is a duplex valve assembly, installed in parallel with the main valve, as a
manual bypass cannot accurately control pressure / flow / temperature without constant
manual supervision. Conversely, a duplex control station will provide proper control, should
the main valve ever need to be removed.
Although not recommended, if a manual bypass valve is fitted, the bypass valve flow
coefficient (Kvs) should be the same as, or near to that of, the control valve. This means that
the manual valve and control valve could have different connection sizes. The bypass valve
should also be capable of throttling not just isolating, to reduce wear on the valve when in
service and to facilitate manual control.
Ideally, any bypass pipework should be arranged either above or alongside the main
assembly. On steam systems, it should never be below it.
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IM-P100-05 CH Issue 16
3.11 Safety valve
A safety valve should be fitted to protect the downstream equipment from excessive
pressure. It should be set to lift below the safe working pressure of the downstream
equipment, and will normally be sized to pass the full capacity of the PRV should the PRV
fail in the fully open position. The safety valve set pressure should take account of its reseat
characteristic and the 'No-load' pressure setting of the PRV. For example, the typical
blowdown value (reseat differential) for a DIN type safety valve is 10% of set pressure. The
minimum possible safety valve set pressure must therefore equal the no load set pressure
of the reducing valve plus the blowdown value of the safety valve plus a small margin of at
least 0.1 bar. If the set pressure is any lower, if whatever reason the safety valve lifts it will
not shut properly and will simmer, creating a leak which is often wrongly diagnosed as a
result of a leaking reducing valve.
Discharge pipework should be taken to a safe place.
3.12 Position in relation to other control valves
Line or system isolation valves (A), either remotely actuated or manual, should be installed
on the upstream side of the DP17 reducing valve.
Where there is downstream control equipment (B), particularly when it is fast acting (for
instance pulsed piston actuated valves) ensure the control equipment is at least 50 pipe
diameters away from the DP17 to prevent pressure pulses being transmitted back causing
unstable operation and premature wear or if this is impractical an intermediate vessel can
provide a similar benefit.
Where a safety valve (C) is required to protect the system downstream of a DP17 and where
a control valve is also being used downstream of the DP17, it is recommended that the safety
valve is fitted downstream of the control valve rather than in between the DP17 and the
control valve. If any slight leakage occurs this will avoid any pressure build-up causing
nuisance operation of the safety valve but provide complete protection for the downstream
system.
Where valves are installed downstream of the DP17 (B) the intermediate downstream
pipework must be properly trapped (D) to ensure no condensate can buil up on the
downstream side of the DP.
C
A
B
A
D
Fig. 7 DP17 position in relation to other control equipment
IM-P100-05 CH Issue 16
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4. Commissioning
4.1 Setting procedure (Fig. 8 and Fig. 9)
1. Ensure that all connections are properly made and that all valves are closed.
DP17, DP17E, DP17G,
DP17Y and DP27G (Fig. 8)
2.Close all valves at reducing valve station,
including valves on bypass line if fitted.
3.Check that adjustment screw is turned fully
anticlockwise until spring is slack.
DP17R (Fig. 9)
2.Close all valves at reducing valve station,
including the valve on the bypass line, if fitted.
3.Check that the actuating air supply is off
and the pressure is zero.
4.Check that the pressure gauge isolating cocks are open.
5.For correct operation of the valve it is important that the pilot and main
valves are not subjected to dirt or other hard particles. Therefore, prior
to bringing the valve into operation, ensure that the upstream pipework
has been cleared of all loose dirt and hard particles and that the main
strainer screen is examined and cleaned if necessary.
6. Slowly open the upstream isolating valve until it is fully open.
DP17, DP17E, DP17G, DP17Y and DP27G
7. Using a 19 mm A/F spanner slowly turn
adjustment screw in a clockwise direction
until desired downstream pressure reading
is obtained.
8. Holding the adjustment screw in position
with the spanner tighten down the lock-nut
to secure the setting of the adjustment
spring,making sure that the 'C' washer
stays in position.
DP17R
7. Slowly admit actuating air through the
pressure regulator until the desired
downstream pressure is obtained.
Note
To facilitate resetting of the reducing valve it
may be desirable to position the downstream
pressure gauge at a viewpoint close to the air
regulator.
If this necessitates fitting the pressure gauge
below the steam line, the interconnecting pipe
should be drained at the low point otherwise
the gauge will give a false reading.
9. Slowly open the downstream valve until it is fully open.
Note: After installation or maintenance ensure that thet system is fully functional. Carry out
tests on any alarms or protective devices.
WARNING
Direct injection systems
This product contains a rust inhibitor to protect it against corrosion during storage.
To avoid any possible contamination of your product, after first blowing down the
approach pipework, we recommend that the valve is blown through thoroughly in
order to remove any trace of the inhibitor.
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IM-P100-05 CH Issue 16
4.2 Two or more valves in parallel
When more than one reducing valve is used it is an advantage to use two valves of unequal
size, the smaller one being chosen to meet the lower load requirements and the larger valve
to come into operation so that both meet the normal and maximum demand.
It is necessary to commission each valve independently (one at a time) following the
procedure detailed in Section 4.1 but setting the smaller valve at a pressure higher than the
larger valve.
2
Optional bypass line (see Section 3.10)
2, 6
2, 9
3
4
Steam flow
4
5
]
5
Condensate
return
] See Section 3.6, page 11
Fig. 8 Setting procedure sequence DP17, DP17E, DP17G, DP17Y and DP27G
2
Optional bypass line (see Section 3.10)
2, 6
4
2, 9
3, 7, 8
4
Steam flow
5
]
5
Condensate
return
] See Section 3.6, page 11
Fig. 9 Setting procedure sequence DP17R
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5. Maintenance
Note: Before actioning any maintenance programme observe
the 'Safety information' in Section 1.
Warning:
The body gasket (all DP17 derivatives) and actuating chamber gasket (DP17R)
contains a thin stainless steel support ring which may cause physical injury
if not handled and disposed of correctly.
5.1 Routine maintenance
It is recommended that the valve is dismantled once every twelve to eighteen months for a
complete overhaul and ideally this should be carried out with the valve removed from the line.
The following parts should be inspected and refurbished or replaced as necessary:
- Main valve seat and valve head.
-Pilot valve chamber assembly.
-Main valve screen.
-Main diaphragms.
-Pilot diaphragms.
Body gasket
(see warning above)
Pilot diaphragms
Pilot valve
chamber assembly
Main valve screen
Main valve seat
and valve head
Main
diaphragms
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To renew or change the control spring
It is not necessary to isolate the valve in order to change the spring.
1. Release the lock-nut.
2.Turn the adjustment screw anticlockwise. Ensure there is no compression on the pressure
adjustment spring.
3.For the DP17 and derivatives only - Slide out the 'C-shape' washer.
4. Remove the cover.
5.For the DP17 - Remove the pressure adjustment spring and top plate.
For the DP27G - Firstly undo the 4 off spring housing securing nuts and remove the spring
housing. Then remove the pressure adjustment spring and the top spring plate.
6. Reassemble in reverse order.
DP17
DP17
DP27G
2
1
1
3
4
8
4
5
5
7
7
7
7
To renew the pilot valve assembly
DP17, DP17E, DP17G , DP17Y and DP27G
Isolate the pressure reducing valve and zero the pressure. Follow Steps 1 to 5 then proceed.
DP17R
Isolate the actuating air supply and zero the pressure.
7. Unscrew the unions and release the pipework.
8.DP17, DP17E, DP17G and DP17Y
Unscrew the spring housing nuts and remove the spring housing, bottom spring plate and
diaphragms.
DP27G
Undo the 4 off spring housing securing nuts and remove the spring housing. Then remove
the pressure adjustment spring, top spring plate, bottom spring plate and diaphragms.
DP17R
Unscrew the securing nuts and remove the air control block and diaphragms.
IM-P100-05 CH Issue 16
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9. Remove the pilot valve housing.
10. Ensure that the main valve return spring is still in position. Any trapped dirt or scale
should be removed from the pilot valve assembly. If appropriate, the complete pilot valve
chamber assembly can be refitted following Steps 14 to 21. If necessary, the complete
pilot valve chamber assembly should be replaced as follows:Note: The pilot valve assembly is no longer available as a standard spare. Because of the
difficult process described in Step 13, it has now been discontinued. The complete pilot
valve chamber assembly is the recognised spare. However for customers with pilot valves
only still in stock, these can be used by following Steps 11-13. This assembly contains 2 off
PTFE seals. The following handling precautions should be observed.
Handling precautions for PTFE
Within its working temperature range PTFE is a completely inert material, but when heated
to its sintering temperature it gives rise to gaseous decomposition products or fumes which
can produce unpleasant effects if inhaled. Fumes can be produced during processing: for
example, when the material is heated to sinter it, or when brazed connections are
being made to cable insulated PTFE. The inhalation of these fumes is easily prevented by
applying local exhaust ventilation to atmosphere as near to their source as possible.
Smoking should be prohibited in workshops where PTFE is handled because tobacco
contaminated with PTFE will during burning give rise to polymer fumes. It is therefore
important to avoid contamination of clothing, especially the pockets, with PTFE and to
maintain a reasonable standard or personal cleanliness by washing hands and removing
any PTFE particles lodged under the fingernails.
11. Unscrew and remove the pilot valve assembly (22 mm A/F)
12. Screw the new pilot valve into the housing. Torque 45 - 50 N m (33 - 37 lbf ft).
13. Check that there is a very slight clearance between the top of the plunger and a straight
edge placed across the diaphragm location recess. (N.B. Because of production
tolerances the plunger is supplied slightly longer than is always required and it will
generally be necessary to grind or machine material off the top end to give the correct
length). After machining make sure the sharp edges are removed from the top of the
plunger as these could damage the diaphragm.
14.Remove the screen and clean. Ensure that the gasket faces are clean.
15. Ensure that the main valve return spring is still in position.
16. Fit new gasket.
17. Replace the screen. Assemble the pilot valve housing.
18. Refit the two diaphragms making sure that they are fitted the same way round as they
were removed and that all contact faces are clean. Diaphragms showing signs of wear
or damage should be replaced.
19. D P17, DP17E, DP17G, DP17Y and DP27G
Replace bottom spring plate.
20. D P17, DP17E, DP17G, DP17Y and DP27G
Assemble the spring housing and tighten the nuts to the recommended torques shown
in Table 1, page 19.
DP17R
Assemble the air control block and tighten the nuts to the recommended torques shown
in Table 1, page 19.
21. Refit the pipework and retighten the unions to ensure a steam tight seal.
Bring the valve back into commission by following as many Steps as are necessary in
Section 4, page 14.
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IM-P100-05 CH Issue 16
9
20
10
19
18
21
17
21
16
11
14
17
14
15
12
13
Table 1
Recommended tightening torques for pilot valve chamber nuts
Size of valve
½", ¾", 1"
DN15, DN20, DN25 and DN32
DN40 and DN50
IM-P100-05 CH Issue 16
Nut size
M10
M12
Tightening torques
40 - 50 N m
(30 - 37 lbf ft)
45 - 55 N m
(33 - 41 lbf ft)
21
To clean the strainer screen
DP17, DP17E, DP17G, DP17Y and DP27G
Isolate the pressure reducing valve and zero the pressure. Follow Steps 1 to 5 then proceed.
DP17R
Isolate the actuating air supply and zero the pressure.
22. Unscrew the unions and release the pipework.
23. Unscrew the nuts. Note that this has already been actioned under step 5 for the DP27G.
24. DP17, DP17E, DP17G, DP17Y and DP27G
Remove the pilot valve housing; complete with the spring housing assembly.
DP17R
Remove the pilot valve housing, complete with air control block.
25. Remove the main valve screen and clean.
DP17 shown
DP17 shown
23
24
30
25
22
22
29
31
28
31
26
27
26. Ensure that the gasket faces are clean.
27. Check that the main valve return spring is in position.
28. Fit a new gasket.
29. Replace the main valve screen.
30. DP17, DP17E, DP17G and DP17Y
Assemble the pilot valve housing complete with the spring housing assembly and tighten
the nuts to the recommended torques shown in Table 1, page 19.
DP17R
Assemble the pilot valve housing complete with the air control block and tighten the nuts
to the recommended torques shown in Table 1, page 19.
31. Refit the pipework and retighten the unions to ensure a tight seal.
Bring the valve back into commission by following as many steps as are necessary in
Section 4, page 14.
22
IM-P100-05 CH Issue 16
To renew pilot valve diaphragms
DP17, DP17E, DP17G, DP27G and DP17Y
Isolate the pressure reducing valve and zero the pressure. Follow Steps 1 to 5 then proceed.
DP17R
Isolate the actuating air supply and zero the pressure.
32. DP17, DP17E, DP17G, DP17Y and DP27G
Unscrew the spring housing nuts and remove the spring housing, bottom spring plate
and old diaphragms.
DP17R
Unscrew the securing nuts and remove the air control block and old diaphragms.
33. Ensure that all contact faces are cleaned. New diaphragms should be fitted such that the
precoated sealant (which is only applied to one diaphragm) faces down contacting the
sealing face of the diaphragm chamber.
34. DP17, DP17E, DP17G, DP17Y and DP27G
Replace the bottom spring plate.
35. DP17, DP17E, DP17G, DP17Y and DP27G
Assemble the spring housing and tighten the nuts to the recomended torque shown in
Table 1, page 19.
DP17R
Assemble the air control block and tighten the nuts to the recommended torques shown
in Table 1, page 19.
Bring the valve back into commission by following as many Steps as are necessary in
Section 4, page 14.
35
32
37
36
34
33
39
38
To renew or clean the main diaphragms
Isolate the pressure reducing valve and zero the pressure. Follow Steps 1 to 5 then proceed.
36.Undo the long union nut and pull away.
37. Undo the M12 nuts and bolts.
38.Drop away the lower diaphragm chamber, two diaphragms, diaphragm plate and
pushrod assembly.
39.Thoroughly clean the lower diaphragm chamber making sure that the contact faces
are clean.
IM-P100-05 CH Issue 16
23
40. Replace the diaphragm plate and pushrod assembly and loosely fit the lower diaphragm
chamber on the two bolts either side of the union connection to locate the spigot in the
recess.
41. Bring the two new diaphragms together (where precoated sealant is applied this should
face outwards) and slide into position.
If the diaphragms are not renewed, but cleaned only, care must be taken to replace the
diaphragms in their original order.
42. Push the lower diaphragm chamber home to locate in the recess and refit the M12 nuts
and bolts. Progressively and evenly tighten to a torque of 80 - 100 N m (59 - 74 lbf ft).
43. Retighten the long union nut to ensure a steam tight seal.
Bring the valve back into commission by following as many Steps as are necessary in
Section 4, page 14.
41
40
45
43
46
42
47
44
44
DP27G shown
To service or renew the main valve and seat
DP17, DP17E, DP17G , DP17Y and DP27G
Isolate the pressure reducing valve and zero the pressure. Follow Steps 1 to 5 then proceed.
DP17R
Isolate the actuating air supply and zero the pressure.
44. Unscrew the unions and release the pipework.
45. Unscrew the spring housing nuts.
46. DP17, DP17E, DP17G, DP17Y and DP27G
Remove the pilot valve housing, complete with the spring housing assembly.
24
IM-P100-05 CH Issue 16
DP17R
Remove the pilot valve housing, complete with the air control block.
47. Remove the main valve, screen and clean.
48. Remove the main valve spring and the main valve head. Clean to remove dirt or scale as
is necessary.
49. Remove the main valve seat. Clean and remove dirt and scale as is necessary.
Examine the faces of the main valve head and seat. If they are only slightly worn both the
main valve head and main seat may be lapped on a flat plate using a fine grinding paste.
If either is badly worn or unfit for further use they will need to be replaced. Clean to remove
dirt or scale as necessary.
DP17G
If there is any wear or damage to the nitrile face then the head assembly must be replaced.
50. Refit the valve seat applying jointing compound to the seating faces and tighten to the
recommended torque shown in Table 2, page 24.
Where a new part has been fitted it will be necessary to reset the main valve pushrod to
give the correct valve lift. To do this it is necessary to expose the main diaphragm plate
and pushrod assembly.
52
48
50
51
49
53
51. Undo the long nuts and pull away.
52. Undo the M12 nuts and bolts.
53. Drop away the lower diaphragm chamber, the two diaphragms, diaphragm plate and the
pushrod assembly.
IM-P100-05 CH Issue 16
25
Table 2 Recommended tightening torques for the main seat
Size of valve
½" and ½" LC
DN15 and DN15LC
¾" and DN20 1" andDN25 DN32
DN40
DN50
Width across flats
Tightening torques
30 mm A/F (External)
110 - 120 N m
(81 - 89 lbf ft)
36 mm A/F (External)
19 mm A/F (Inside)
24 mm A/F (Inside)
30 mm A/F (Inside)
41 mm A/F (Inside)
140 - 150 N m
230 - 250 N m
300 - 330 N m
450 - 490 N m
620 - 680 N m
(103 - 111 lbf ft)
(170 - 184 lbf ft)
(221 - 243 lbf ft)
(332 - 361 lbf ft)
(456 - 502 lbf ft)
54.Refit the pushrod assembly.
55.Refit the main valve head, making sure that the valve locates on the seat.
56.Check the valve lift shown in Table 3 using a depth gauge.
Depth gauge
55
56
59
57
54
Table 3
58
56
Size of valve
DN15LC and ½" LC
DN15 and ½"
DN20 and ¾"
DN25 and 1"
DN32 DN40 DN50 Valve lift
2.5 mm
(0.098")
2.5 mm
(0.098")
2.5 mm
(0.098")
3.0 mm
(0.118")
3.5 mm
(0.138")
4.5 mm
(0.177")
5.0 mm
(0.197")
Adjust if necessary by screwing the pushrod in or out of the diaphragm plate.
26
IM-P100-05 CH Issue 16
57. Thoroughly clean the lower diaphragm chamber making sure that the contact faces are
clean.
58. Replace the diaphragm plate and pushrod assembly and loosely fit the lower diaphragm
chamber on to the two bolts either side of the union connection to locate the spigot in
the recess.
59. Refit the diaphragms in exactly the same way as when dismantled.
60. Push the lower diaphragm chamber home to locate in the recess and refit the M12 nuts and bolts. Progressively and evenly tighten to a torque of 80 - 100 N m (59 - 74 lbf ft).
61. Retighten the long union nut to ensure a steam tight seal.
61
60
66
64
63
67
64
67
62
DP27G shown
62. Refit the main valve head.
63. Replace the main valve return spring.
64. Fit a new gasket.
65. Replace the screen.
66. DP17, DP17E, DP17G, DP17Y and DP27G
Assemble the pilot valve housing complete with the spring housing assembly and tighten
the nuts to the recommended torques shown in Table 1, page 19.
DP17R
Assemble the pilot valve housing complete with the air control block and tighten the nuts
to the recommended torques shown in Table 1, page 19.
67. Refit the pipework and retighten the unions to ensure a tight seal.
Bring the valve back into commission by following as many Steps as necessary in Section 4,
page 14.
IM-P100-05 CH Issue 16
27
To service or renew solenoid valve
DP17E
Depressurize the valve and turn off the electrical power supply.
68. Undo the retaining nut and slip the entire solenoid enclosure off the solenoid base and
sub-assembly or plugnut / core tube sub-assembly.
69. Unscrew the bonnet or solenoid base sub-assembly and remove the core spring, core
assembly and body gasket.
All the parts are now accessible for cleaning or replacement. Replace worn or damaged
parts with a complete Spare parts kit (item 'W', pages 28 and 29) for best results.
70. Reassemble in reverse order paying careful attention to exploded views provided.
68
71
70
72
69
CAUTION
The solenoid must be fully reassembled as the housing
is part of, and completes the magnetic circuit.
Coil replacement
Switch off the electrical power supply and disconnect the coil lead wires.
71. Undo the retaining nut.
72. Slip the washer, insulating washers and coil off the solenoid base sub-assembly.
Reassemble in reverse order (see the CAUTION above).
28
IM-P100-05 CH Issue 16
6. Spare parts
Interchangeability of spares
The following table shows how in certain sizes some parts are interchangeable. For example
in the line headed 'Main diaphragm' the diaphragm used in the screwed valves ½" and ¾"
is common to these sizes by the letter 'a', the letter 'c' indicates that one diaphragm is
common to the DN40 and DN50 valves. All spares are interchangeable with the DP17T and
where marked † are interchangeable with the 37D temperature control.**
** Note: This does not apply to DP17G soft seat pilot valve or main valve assemblies.
†
†
†
†
†
†
†
†
Screwed
***
Size DN ½"LC ½" ¾"
Maintenance kit
a
a a
Main diaphragm
a
a a
Pilot diaphragms
a
a a
Pilot valve chamber assembly
a
a a
PTFE seals
a
a a
Main valve assembly
a
b c
Internal strainer
a
a a
Main valve return spring
a
a a
Pressure adjustment spring
a
a a
Control pipe assembly
a
a a
Balance pipe assembly
a
a a
Body gasket
a
a a
Set of spring housing
a
a a
securing studs and nuts
Set of main body studs and nuts
a
a a
Set of diaphragm
a
a a
securing bolts and nuts
Pushrod and main diaphragm
a
a a
plate assembly
Flanged
1"
b
b
a
a
a
d
b
a
a
b
b
a
***
15LC
f
a
a
a
a
a
f
a
a
f
f
a
a
15 20 25
f a b
a a b
a a a
a a a
a a a
b c d
f a b
a a a
a a a
f a b
f a b
a a a
32
c
b
a
a
a
e
c
a
a
c
c
a
40
d
c
a
b
a
f
d
c
a
d
d
b
50
e
c
a
b
a
g
e
c
a
e
e
b
a
a
a
a
a
b
b
a
a
a
a
a
a
b
b
a
a
a
a
a
a
b
b
b
a
a
a
b
b
c
c
*** Not available for DP17G
IM-P100-05 CH Issue 16
29
Spare parts
The spare parts available are shown in solid outline. Parts drawn in broken line are not available
as spares.
Available spares
Maintenance kit
A stand-by set of spares for general maintenance purposes and covers all spares marked *
A
* Main diaphragm (2 off)
* Pilot diaphragm (2 off)
* Pilot valve chamber assembly (8 pieces)
B
C, C1
K, L
Main valve assembly
M
* Internal strainer
* Main valve return spring
N
Pressure adjustment spring DP17, DP17E, DP17G and DP27G 0.2 to 17 bar (3 to 247 psi)
O
(Not required for DP17R) DP17Y
0.2 - 3 bar (3 - 44 psi)
Control pipe assembly
P
* Balance pipe assembly
* Body gasket (3 off) Q
R
Set of spring housing / actuating chamber cover securing studs and nuts (set of 4) Set of main body studs and nuts (set of 4)
Set of diaphragm securing bolts and nuts Valve sizes ½" - DN32 (set of 10)
Pushrod and main diaphragm plate assembly
DN40 and DN50 (set of 12)
S
T
V
Y
Type DP17E only
Solenoid valve complete
W
Replacement coil
X1
Valve seat and core assembly
X2
How to order spares
Always order spares by using the description given in the column headed 'Available spares'
and state the size and type of the pressure reducing valve.
Example:
1 - Main valve assembly for a Spirax Sarco 1" DP17 pilot operated pressure reducing valve.
30
IM-P100-05 CH Issue 16
DP17
DP17R
DP27G
S
O
S
B
Q
X1
C1
C
W
R
P1
X2
P
Solenoid valve complete
Main valve assembly Pilot valve chamber assembly
S
T
R
V
T
N
K
L
A
Y
M
V
IM-P100-05 CH Issue 16
31
7. Fault finding
7.1 Preliminary procedure
Before undertaking the following fault finding procedure, ensure that the valve has been
isolated and that upstream and downstream pressures are zero. Possible fault checks are
given in a logical order below.
7.2 Downstream pressure zero or too low
If downstream pressure drops below set pressure or is zero, check the following:
1. No high pressure steam reaching the pressure reducing valve. Check that steam is
turned on and that the strainer is clear. (To assist with commissioning and fault finding
it is recommended to fit an upstream pressure gauge).
2. Pressure adjustment spring broken.
3. Pipe assembly (Item 'P' on page 29) blocked. Remove by uncoupling the union nuts and
blow through to clear obstruction.
4. Control orifice blocked. Unscrew from the outlet port and clear out obstruction. For
identification this coupling has a groove around the hex.
5. Main diaphragms fractured. Replace the diaphragms following Steps 36 to 43.
6. Pilot valve plunger too short. Check as Section 5 Step 13.
7. Valve capacity insufficient for downstream conditions.
a) Check that the upstream pressure is correct. If it is low, the capacity of the valve will
be reduced.
b) Ensure that the pressure control pipe is fitted as recommended in Section 3.8 and
if necessary fit an external pressure control pipe as described. If the downstream
pressure is still too low, then a larger valve with more capacity is required.
7.3 Downstream pressure too high
If the pressure on the downstream side of the pressure reducing valve has risen above the
required set pressure check the following:
1. Downstream pressure control pipe blocked. Dismantle and blow through.
2. Control orifice (item 'P1' on page 29) blocked. Unscrew the pipework from the side of
the body and clean out. For identification this coupling has a groove around the hex.
3. Pilot valve diaphragms fractured. Check and replace (see page 21).
4. Pilot valve or pilot valve plunger is sticking. Follow Steps 7 to 11.
5. Main valve not seating. Check as page 22.
6. Main valve pushrod sticking. Follow Steps 36 to 43.
7. Pilot valve plunger too long. Check as Section 5 Step 13.
8. Pilot valve not seating. Refer to procedure on page 17.
32
IM-P100-05 CH Issue 16
7.4 Hunting
Hunting may coincide with variations in steam load. If this is the case, the following checks
should be made before dismantling the valve:
1. Check that the upstream pressure is stable. If the pressure drops during full-load
conditions, it is possible that there is a partial blockage upstream, or that the upstream
pipework is undersized. If the upstream pressure is low, the effect will be to reduce the
capacity of the valve with the possibility of not maintaining the downstream pressure during
full-load conditions.
2. If the upstream pressure is correct, and stable, set the valve on dead-end conditions.
Apply full-load to the valve.
If the downstream pressure drops excessively during full-load condition, it is likely that
the valve is undersized, in which case it should be replaced.
Once it has been determined that the upstream pressure is correct and stable, and that
the valve is correctly sized, the following check should be carried out on the valve:
3. Steam is very wet. Ensure the valve installation is as recommended in Fig. 4, page 10.
4. The point at which the external pressure control pipe is tapped into the main is in a
turbulent area. Refer to Section 3.8 for guidance.
5. Loose dirt in the pipe assembly (Item 'P' on page 29). Remove the pipe assembly. Blow
through to clear.
6. Pilot valve or pilot valve plunger is sticking. Follow Steps 7 to 11.
7. Main valve pushrod sticking. Follow Steps 36 to 43.
8. Pilot diaphragms or main diaphragms overstretched. To replace, see page 21.
IM-P100-05 CH Issue 16
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IM-P100-05 CH Issue 16
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IM-P100-05 CH Issue 16
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