Spirax Sarco DP27S User manual

IM-IBR16-27IN Issue 6 1
1. Safety information
2. General
product information
3. Installation
4. Commissioning
5. Maintenance
6. Spare parts
7.Faultnding
© Copyright 2016
Printed in India
DP27S and DP27SY
Pilot Operated Pressure Reducing Valves
Installation and Maintenance Instructions
IM-IBR16-27IN
Issue 6

IM-IBR16-27IN Issue 6
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1. Safety information
Safe operation of these products can only be guaranteed if they are properly
installed, commissioned, used and maintained by qualied 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 Indian Boiler
Regulations, 1950.
i) The products have been specically designed for use on steam and air. The
product s’ use on oth er ui d s m ay be possible but, if this is contem p lated, Spirax
Sarco should be contacted to conrm the suitability of the product for the
application being considered.
i i ) C h e c k m a t e r i a l s u i t a b i l i t y , p r e s s u r e a n d t e m p e r a t u r e a n d t h e i r m a x i m u m a n d
m i n i m u m v a l u e s . I f t h e m a x i m u m o p e r a t i n g l i m i t s o f t h e p r o d u c t a r e l o w e r t h a n
those of the system in which it is being tted, 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 uid ow.
iv) Spirax Sarco products are not intended to withstand external stresses that may
be induced by any system to which they are tted. 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 lm 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.
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
p r e v i o u s t i m e . C o n s i d e r :  a m m a b l e m a t e r i a l s , s u b s t a n c e s h a z a r d o u s t o h e a l t h ,
extremes of temperature.

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1.5 Hazardous environment around the product
Consider: explosion risk areas, lack of oxygen (e.g. tanks, pits), dangerous gases,
e x t r e m e s o f t e m p e r a t u r e , h o t s u r f a c e s ,  r e h a z a r d ( e . g . d u r i n g w e l d i n g ) , e x c e s s i v e
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.
C o n s i d e r d o u b l e i s o l a t i o n ( d o u b l e b l o c k a n d b l e e d ) a n d t h e l o c k i n g o r l a b e l l i n g
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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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 232°C.
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 landll site.

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2.2 Sizes and pipe connections
Screwed BSP or NPT (DN15, DN20 and DN25 only).
Flanged DN15LC - Low Capacity version, DN15, DN20, DN25, DN32, DN40 and DN50.
DN15 - DN50 ASME 150
Standard flanges: DN15 ASME 300
DN25 - DN50 ASME 300
2. General product information
2.1 General description
These instructions apply to the DP27S and the derivative DP27SY.
The instructions primarily relate to the use of the DP27S on steam but can be used as a
guide when the valve is used on compressed air.
Note: For additional information see the relevant Technical Information Sheets.

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2.3 Pressure / temperature limits
The product must not be used in this region.
For optimum performance, the maximum design pressure should not exceed 17.2 bar g
A-D-C Screwed and flanged ASME 300
A-B-C Flanged ASME 150.
Note: DP27S has a variable rate conical pressure adjustable spring fitted providing a
downstream pressure range of 0.2 - 17 bar g.
DP27SY has a pressure spring with a range of 0.2 - 3 bar g.
Body design conditions PN25
Maximum design pressure 17.2 bar g @ 232°C
Maximum design temperature 232°C @ 17.2 bar g
Minimum design temperature -10°C
Maximum upstream pressure for saturated steam service 17 bar g
Maximum operating temperature 232°C
Minimum operating temperature 0°C
Note: For lower operating temperatures consult Spirax Sarco.
Maximum differential pressure 17 bar
Designed for a maximum cold hydraulic test pressure of: 25.8 bar g


   






Pressure bar g
Temperature °C
A
Steam
saturation
curve
C
BD

IM-IBR16-27IN Issue 6 7
Note: Before actioning any maintenance programme for the pilot operated
pressure reducing valve (PRV) 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
DP27S (Figure 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.
DP27SY (Figure 1)
The DP27SY is supplied as the DP27S, but has a lower rate pressure adjustment spring for
a downstream pressure range of 0.2 - 3 bar.
Pressure adjustment spring
Downstream internal
pressure balance pipe
Pressure setting adjustment screw
Lock-nut
Recommended downstream pressure
balance pipe connection
(refer to Section 3.8, page 10)
Fig. 1
3. Installation

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Pressure
sensing
pipe
Small bore
drain
Strainer with
100 mesh stainless
steel screen
Separator
Steam
supply Spiratec
sensor
chamber
Float type
steam trap
Pressure
reducing
valve
DP27S
0.9 m or
15 pipe diameters clear
on either side
See Section 3.6, page 9
Downstream isolating valve to
provide no-load conditions for
setting pressure reducing valve
Safety
valve
Discharge
pipe
Isolation
valve
Strainer
3.2 Fitting (Figures. 2, 3 and 4)
The valve should always be fitted in a horizontal pipeline with the main diaphragm
chamber below the line (Figure 2). To meet high capacities or widely varying loads, or
where stand-by facility is required, two or more valves may be used in parallel (Figure 3).
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 Figure 4.
Separator
Compressed
air
Fig. 2 Recommended installation
Installation for
compressed air Compressed
air trap
Float type
steam trap
Alternative for
draining
separator
Strainer Sight
glass
Isolation
valve

IM-IBR16-27IN Issue 6 9
Fig. 3 Two pressure reducing valves in parallel
Steam
supply
Q See Section 3.6
3.3 Pipeline sizing
The piping on both sides of the valve must be sized so that velocities do not exceed 30 m / 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
Q See Section 3.6
Fig. 4 Two pressure reducing valves installed in series
Q
Q
Q
Separator
Trap set Trap set

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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 sensing
For applications that require closer control, improved stability or maximum capacity condition
the internal balance pipe should be replaced by an external pressure sensing pipe
(supplied by others) as follows:
Remove the internal balance 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 used to fit the external
pressure sensing pipe. 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 sensing 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 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 DP27S. Where the size of the
reduced pressure main makes it difficult to maintain a fall when entering the top of the main,
the pressure sensing 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 Continuous duty
For continuous duty applications where a constant steam supply is essential then a parallel
stand-by PRV station is recommended to allow for planned maintenance, see Figure 3,
page 9. Alternatively a bypass line can be used (see Figure 6, page 12). It is important that the
bypass should have a similar capacity to the pressure reducing valve which is achieved by
choosing an appropriately sized valve or by using a reduced orifice in the line.
The handwheel should be padlocked to prevent unauthorised use, and when in use should
be under constant manual supervision.
The bypass may be arranged above or to the side of the main assembly but never below it.

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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 safety
valve lifts and the working pressure is too close then it will not be able to close 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
Fig. 5 DP27S position in relation to other control equipment
D
C
B
AA
Line or system isolation valves (A), either remotely actuated or manual, should be installed on
the upstream side of the DP27S 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 DP27S 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 DP27S and where
a control valve is also being used downstream of the DP27S, it is recommended that the safety
valve is fitted downstream of the control valve rather than in between the DP27S 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 DP27S (B) the intermediate downstream
pipework must be properly trapped (D) to ensure no condensate can build up on the downstream
side of the DP27S.
DP27S

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Fig. 6 Setting procedure sequence DP27S
4. Commissioning
4.1 Setting procedure (Figure 6)
1. Ensure that all connections are properly made and that all valves are closed.
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.
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.
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.
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. It is recommended that after commissioning
the pilot filter is changed and the spare one supplied with the valve is fitted.
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
5
2, 9
3, 7, 8
2, 6
5
44
Condensate
return
Steam flow
Optional bypass line (see Section 3.10)
Q See Section 3.6, page 9
Q

IM-IBR16-27IN Issue 6 13
5. Maintenance
Note: Before actioning any maintenance programme observe the 'Safety
information' in Section 1.
Warning:
The body gasket 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 assembly.
-Pilot filter element.
-Internal strainer screen.
-Main diaphragms.
-Pilot diaphragms.
Pilot diaphragms
Main diaphragms
Main valve seat
and valve head
Internal strainer screen
Pilot filter element
Body gasket
Pilot valve assembly

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5.2 How to renew the pilot filter element
1. Isolate the reducing valve and zero the pressure.
2. Unscrew the filter cap and carefully withdraw the filter
element.
3. Replace the element and tighten the filter cap to
90 - 100 N m.
Note: The gasket is re-usable.
Filter
element
Filter cap
5.3 How to renew or change the
pressure adjustment spring
Isolate the reducing valve and zero the pressure in order to
change the pressure adjustment spring.
1. Release the adjustment lock-nut.
2. Turn the adjustment screw anticlockwise. Ensure there
is no compression on the pressure adjustment spring.
3. Undo the 4 off spring housing securing nuts and remove
the spring housing.
4. Remove the pressure adjustment spring and the top
spring plate.
5. Reassemble in reverse order.
1
2
3, 6
4
5.4 How to renew the pilot valve assembly
6. Isolate the reducing valve and zero the pressure and proceed to unscrew the 4 off spring
housing securing nuts and remove spring housing, bottom spring plate and diaphragms.

IM-IBR16-27IN Issue 6 15
9
10. 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.
11. Replace the bottom spring plate.
12. Assemble the spring housing and tighten the nuts to the recommended torques
shown in Table 1.
Bring the valve back into commission, following as many Steps as necessary in Section 4,
page 12.
Straight edge
7. Unscrew and remove the pilot valve assembly (19 mm A/F). The pilot assembly has
an integral PTFE seal.
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.
8. Apply superlube grease to the threads before screwing the new pilot valve into the housing.
Torque 45 - 50 N m.
9. Check that there is a very slight clearance between the top of the plunger and a straight
edge placed across the diaphragm location recess.

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Table 1
Recommended tightening torques for spring
housing/actuating chamber cover securing studs and nuts
Size of valve Nut size Tightening torques
DN15, DN20, DN25 and DN32 M10 40 - 50 N m
DN40 and DN50 M12 45 - 55 N m
12
7
10
11
8

IM-IBR16-27IN Issue 6 17
5.5 How to clean or replace the internal strainer screen
Isolate the reducing valve and zero the pressure.
13. Unscrew the unions and release the pipework.
14. Unscrew the nuts.
15. Remove the pilot valve housing; complete with spring housing assembly.
16. Remove the internal strainer screen and clean or replace.
17. Ensure the gasket faces are clean.
18. Check that the main valve return spring is in position.
19. Fit a new gasket.
20. Replace the internal strainer screen.
21. Assemble the pilot valve housing complete with spring housing assembly and tighten
the nuts to the recommended torques shown in Table 1, page 16.
22. Refit the pipework and retighten unions to ensure a tight seal.
Bring the valve back into commission, following as many steps as necessary in Section 4,
page 12.
14
15
13
13 16 22
20
19
18
14 21
17
17

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5.6 How to renew the pilot valve diaphragms
Isolate the reducing valve and zero the pressure.
23. Unscrew the nuts and remove: spring housing, bottom spring plate and old diaphragms.
24. 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.
25. Replace the bottom spring plate.
26. Assemble the spring housing and tighten the nuts to the recomended torque shown in
Table 1, page 16.
Bring the valve back into commission, following as many Steps as necessary in Section 4,
page 12.
23 26 28
27
30
29
25
24
5.7 How to renew or clean main diaphragms
Isolate the reducing valve and zero the pressure.
27. Undo the long union nut and pull away.
28. Undo the M12 nuts and bolts.
29. Drop away the lower diaphragm chamber, the two diaphragms, diaphragm plate and
the pushrod assembly.
30. Thoroughly clean the lower diaphragm chamber making sure contact faces are clean.

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31. Replace the diaphragm plate and pushrod assembly and loosely fit the lower diaphragm
chamber on two bolts either side of the union connection to locate the spigot in the recess.
32. 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.
33. 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.
34. Retighten the long union nut to ensure a steam tight seal.
Bring the valve back into commission, following as many Steps as necessary in Section 4,
page 12.
5.8 How to service or renew the main
valve and seat
Isolate the reducing valve and zero the pressure.
35. Unscrew the unions and release the pipework.
36. Unscrew the nuts.
32
31
34
33
36
37
35
35

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37. Remove the pilot valve housing, complete with spring housing assembly.
38. Remove the main valve plus internal strainer screen and clean.
39. Remove the main valve spring and the main valve head. Clean to remove dirt or scale
as necessary.
40. Remove the main valve seat. Clean and remove dirt and scale as necessary.
Note: Examine the faces of the main valve head and seat. If they are only slightly worn
they may be lapped on a flat plate using a fine grinding paste. If either is badly worn or
unfit for further use they must be replaced.
41. Refit the valve seat applying jointing compound to the seating faces and tighten to the
recommended torque shown in Table 2, page 21.
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.
42. Undo the long nuts and pull away.
43. Undo the M12 nuts and bolts.
44. Drop away the lower diaphragm chamber, the two diaphragms, diaphragm plate and
pushrod assembly.
41
38, 39
40
42 43
44