Spirax Sarco DP143 User manual

IM-P006-07 CTLS Issue 12 1
1. Safety information
2. General product information
3. Installation
4. Commissioning
5. Maintenance
6. Spare parts
7. Fault finding
© Copyright 2018
Printed in GB
0060026/12
DP143, DP143G, DP143H
and DP163, DP163G, DP163Y
Pilot Operated Pressure Reducing Valves
Installation and Maintenance Instructions
IM-P006-07
CTLS Issue 12

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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 these 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 Pressure Equipment Directive (PED)
and carry the mark when so required. The products fall within the following Pressure
Equipment Directive categories:
Product Group 2
Gases
DP143 and all derivatives
DN15 - DN32 SEP
DN40 - DN80 1
DP163 and all derivatives
DN15 - DN32 SEP
DN40 - DN80 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 allname-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. Safety information

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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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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.
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.
1.16 Returning products
Customers and stockists are reminded that under EC Health, Safety 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 health,
safety 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.
Warning
If this product is not used in the manner specified by this IMI, then the protection provided
may be impaired.

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These instructions relate to the use of the DP143
(Section 2.1) and DP163 (Section 2.2) pilot operated
pressure reducing valves on steam applications but can be
used as a guide when the valve is used on compressed air
applications. The DP143G and DP163G are recommended
for compressed air applications, both having a nitrile seal
for the main valve and pilot valve assemblies.
Note: For additional information see the relevant Technical
Information Sheet.
2.1 DP143, DP143G and DP143H
2.1.1 Description
The DP143, DP143G and DP143H pilot operated pressure
reducing valves have been manufactured using cast steel.
Available types
DP143 Suitable for steam applications
DP143G Is a soft seal version available for
compressed air and inert industrial
gases.
Note: It is not recommended for
oxygen service.
DP143H Is a high temperature version for use up
to 350 °C.
Sizes and pipe connections
DN15LC - Low Capacity version, DN15, DN20, DN25, DN32, DN40, DN50 and DN80.
Standard flanges: EN 1092 PN25 and PN40, BS 10 Table 'J' and ASME 300.
Available on request: ASME 150 and JIS 20.
2. General product information

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0
0
100
200
300
350
10 17.2 20 26 30 40
2.1.2 Pressure/temperature limits
Pressure bar g
Temperature °C
A B
F
Steam
saturation
curve
D
EGC
The product must not be used in this region.
Use the high temperature DP143H version in this region.
A-D-EFlanged EN 1092 PN40, ASME 300 and BS 10 Table J.
A-B-CFlanged ASME 150.
F-GDP143G limited to 120 °C @ 26 bar g.
Note: Two colour coded pressure adjustment springs are available for the following downstream pressure
ranges:
Red 0.2 bar g to 17 bar g
Grey 16.0 bar g to 24 bar g
Body design conditions PN40
Maximum design pressure
A-D-E40 bar g @ 40 °C
A-B-C17.3 bar g @ 40 °C
Maximum design temperature 350 °C @ 24 bar g
Minimum design temperature 0°C
Maximum upstream pressure for saturated steam service
A-D-E28 bar g
A-B-C14 bar g
Maximum operating temperature
DP143 300 °C @ 25 bar g
DP143G 120 °C @ 26 bar g
DP143H 350 °C @ 24 bar g
Minimum operating temperature
Note: For lower operating temperatures consult Spirax Sarco.
0°C
Maximum differential pressure
A-D-E28 bar
A-B-C14 bar
Designed for a maximum cold hydraulic test pressure of: 60 bar g
Note: With internals fitted, test pressure must not exceed: 40 bar g

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2.2 DP163, DP163G and DP163H
2.2.1 Description
The DP163, DP163G and DP163Y pilot operated
pressure reducing valves have been manufactured
using stainless steel.
Available types
DP163 Suitable for steam applications
DP163G Is a soft seal version available for compressed
air and inert industrial gases.
Note: It is not recommended for oxygen
service.
DP163Y Having a lower rate pressure control spring is
suitable for steriliser/autoclave applications
2.2.2 Sizes and pipe connections
DN15LC - Low Capacity version, DN15, DN20, DN25, DN32, DN40, DN50 and DN80.
Standard flanges: EN 1092 PN25 and PN40, BS 10 Table 'J' and ASME 300.
Available on request: ASME 150 and JIS 20.

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0 10 18.9 26 30 36.4 40
0
50
100
150
200
250
Pressure bar g
Temperature °C
2.2.3 Pressure/temperature limits
A B D
G EC
F
Steam
saturation
curve
The product must not be used in this region.
A-D-EFlanged EN 1092 PN40, BS 10 Table J and ASME 300.
A-B-CFlanged ASME 150.
F-GDP163G limited to 120 °C @ 26 bar g.
Note: Two colour coded pressure adjustment springs are available for the following downstream
pressure ranges:
Red 0.2 bar g to 17 bar g
Grey 16.0 bar g to 21 bar g
Yellow 0.2 bar g to 3.0 bar g (DP163Y only)
Body design conditions PN40
Maximum design pressure
A-D-E36.4 bar g @ 20 °C
A-B-C18.9 bar g @ 20 °C
Maximum design temperature 250 °C @ 24 bar g
Minimum design temperature -10 °C
Maximum upstream pressure for saturated steam service
A-D-E25 bar g
A-B-C14 bar g
Maximum operating temperature
A-D-E250 °C @ 24 bar g
A-B-C250 °C @ 12.1 bar g
Minimum operating temperature
Note: For lower operating temperatures consult Spirax Sarco.
0°C
Maximum differential pressure
A-D-E25 bar
A-B-C14 bar
Designed for a maximum cold hydraulic test pressure of: 60 bar g
Note: With internals fitted, test pressure must not exceed: 40 bar g

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Fig. 1
Balance pipe assembly
Pressure adjustment spring
Note: Before actioning any installation observe the 'Safety information' in Section 1.
3.1 Supply (Figure 1)
The DP143 and DP163 pilot operated pressure reducing valves are supplied ready for fitting. The pressure
adjusted spring will be the one most suitable for the downstream pressure quoted on the order but will not
be pre-set.
3. Installation

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Pressure
control
pipe
Strainer with 100 mesh
stainless steel screen
Separator
Steam
supply
Spiratec
sensor
chamber
Float type
steam trap
Pilot operated
pressure reducing
valve
1 m or 15 pipe
diameters clear on
either side
Downstream isolating valve to provide
no-load conditions for setting pressure
reducing valve
Safety
valve Discharge pipe
Check valve
Strainer
Fig. 2 Recommended installation
Steam supply
3.2 Fitting (Figure 2 and Figure 3)
The valve should always be fitted in horizontal pipework with the main diaphragm chamber below the line.
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. 3
Important DP143 only
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.
Condensate
Condensate

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3.3 Pipeline sizing
The piping on both sides of the valve must be sized so that velocities do not exceed 30 m/sec. This
means that a properly sized valve will often be smaller than the upstream pipework and invariably the
downstream pipework will be larger than the upstream pipework.
3.4 Pipeline stresses
Line stresses such as could be caused by expansion or inadequate support should not be imposed on the
valve body.
3.5 Isolating valves
These should preferably be of the fullway type.
3.6 Removal of condensate
Ensure that the pipework is adequately drained so that the valve is supplied with dry steam. The ideal
arrangement is to fit a separator in the steam supply. If by closing downstream isolating valves, the downstream
pipework is likely to become flooded, a trap set should be installed to remove condensate forming as a result
of radiant losses.
3.7 Preventing dirt
The valve should be protected by a pipeline strainer the same size as the upstream pipework and fitted with
100 mesh screen. The strainer should be fitted on its side to prevent the accumulation of water.
3.8 Pressure sensing
For applications that require closer control, improved stability or maximum capacity condition the balance
pipe should be replaced by an external pressure sensing pipe (supplied by others) as follows:
Remove the 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 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 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 DP valve. 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 downstream side so that the valve can be properly set. A pressure
gauge on the upstream side is an essential diagnostic tool.

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Fig. 4 Setting procedure sequence DP143, DP143G and DP143H
Fig. 5 Setting procedure sequence DP163, DP163G and DP163Y
]See Section 3.6
Condensate
return
Steam flow
Optional bypass line (see Section 3.10)
]
Condensate
return
Steam flow
Optional bypass line (see Section 3.10)
]See Section 3.6
]
3.10 Bypass
If it is essential to maintain a constant supply of steam across the valve. It may be necessary to install a bypass
to ensure continuation of supply when the reducing valve is being serviced Figure 4 and Figure 5.
The bypass valve will normally be the same size as the reducing valve. 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 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 DP 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 DP 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 DP and where a control valve is
also being used downstream of the DP, it is recommended that the safety valve is fitted downstream of the
control valve rather than in between the DP 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 DP (B) the intermediate downstream pipework must be properly
trapped (D) to ensure no condensate can buil up on the downstream side of the DP.
Fig. 6 The position of the pressure reducing valve in relation to other
control equipment
D
C
B
A
A

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4.1 Start-up (Setting the valve)
1. Ensure that all connections are properly made and that all valves are closed.
2. Check that the adjustment is turned fully anticlockwise until the spring is slack.
3. Open small valve in pressure control line.
4. Blow through the approach pipework by removing the cap and screen from the strainer protecting the
steam trap draining the upstream pipework. Replace upon completion. Do not remove the screen from
the main line strainer during this operation. Although this should remove most of the dirt which is present,
it may be necessary to examine and clean the main line strainer at regular intervals.
5. Slowly open the upstream isolating valve until it is fully open.
6. Using a 19 mm A/F spanner slowly turn the adjustment screw in a clockwise direction until the desired
downstream pressure reading is obtained.
7. 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 (Figure 1).
8. Slowly open the downstream valve until it is fully open.
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 set each valve independently following the start-up procedure detailed in Section 4.1 but
setting the smaller valve at some 0.1 bar higher than the larger one.
Each valve should be set against dead end conditions achieved by closing a downstream isolating valve.
4. Commissioning

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Note:
Before actioning any maintenance programme observe the 'Safety information' in Section 1.
Warning:
The body gasket (15) contains a thin stainless steel support ring which may cause physical injury
if not handled and disposed of correctly.
Warning - DP163
The 316 type stainless steel used in the construction of the DP163 product, particularly for screwed
or close fitting parts, is very susceptible to galling or cold welding. This is an inherent characteristic
of this type of material and great care should therefore be taken when dismantling or reassembling.
If the application permits it is recommended that a light smear of a PTFE based grease is applied
to any mating parts before reassembly.
5.1 Routine maintenance
It is recommended that the valve is dismantled once every 12 to 18 months for a complete overhaul and
ideally this should be carried out with the valve removed from the line.
The parts that may require replacing or refurbishing are listed below:
-Main valve (17) and main valve seat (18)
-Pilot valve assembly (13)
-Pilot diaphragms (9)
-Main diaphragms (23)
A detailed procedure for servicing the above items is described in Sections 5.3 to 5.9.
In addition to the above items the pushrod (26) liner bush, and control pipework and fittings should be cleaned
of any scale deposit if necessary.
5.2 Diaphragms and cleaning
If the valve is dismantled and either the main diaphragms or the pilot diaphragm are not renewed care
must be taken not to turn the diaphragms over - refit them in exactly the same position as when dismantled.
The control orifices in the adaptors of the control pipe assembly (27) as well as the balance pipe (19 or
19A) must be kept clear of dirt. Blow through with compressed air if necessary - do not use a drill on the
control orifices, as enlargement of the orifices might upset the operation of the valve.
Main diaphragms used in the DP143 and DP163 reducing valves
Size of valve Diaphragm diameter
DN15, DN15 LC, DN20 125 mm
DN25, DN32 166 mm
DN40, DN50 230 mm
DN80 300 mm
5. Maintenance

IM-P006-07 CTLS Issue 12 17
Fig. 7 24
26
17
18
16
19
19A
29
10
3
12
6
1
2
5
8
7
9
31
11
21
15
13
23
30
25
32
28
4
14
20
22
27

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5.3 Pressure adjustment springs and ranges
Three colour coded adjustment springs are
available for the following reduced pressure
ranges:
Red 0.2 to 17 bar
Grey
DP143 16.0 to 24 bar
DP163 16.0 to 21 bar
Yellow DP163Y 0.2 to 3 bar
5.4 How 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) and turn the adjustment screw (1) anticlockwise until the spring is slack.
2. Slide out the 'C' washer (3) from underneath the lock-nut and remove the cover (12).
3. Remove the old spring (6) and replace it with a new one remembering to replace the top spring
plate (5).
4. Replace the cover and 'C' washer, and turn the adjustment screw clockwise until the desired pressure
reading is obtained.
5. Holding the adjustment screw in position tighten down the lock-nut making sure the 'C' washer stays in
position.
5.5 How to renew the pilot valve assembly and bellows seal
1. Isolate the reducing valve and zero the pressure.
2. Release the lock-nut (2) and turn the adjustment screw (1) anticlockwise until the spring is slack.
3. Slide out the 'C' washer (3) from underneath the lock-nut and remove the cover (12).
4. Remove the spring (6) and top spring plate (5).
5. Undo the 4 x M10 nuts (8) and remove the spring housing (4), bottom spring plate (7) and the
diaphragms (9).
6. Undo the pipework union nuts and release the 6 mm stainless steel pipework.
7. Undo the nuts (21) and remove the pilot valve housing (10) making sure that the main valve spring (16)
is still positioned correctly on top of the main valve head (17).
8. Unscrew the pilot valve assembly (13) which includes the integral strainer screen (14) by using a 27 mm
A/F socket and also remove the plunger (11).
9. Unscrew the bellows seal assembly (31) using a 24 mm A/F socket. If necessary this bellows seal
assembly can be replaced.
10. With the bellows seal still removed screw in the new pilot valve assembly (13) and tighten down to a
torque of 115 N m.
11. Insert the plunger (11) in from the top and check that there is a gap of 0.7 mm between the top of the
plunger and a straight edge placed across the diaphragm location recess (See Figure 8).
Note: 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 bellows. The 0.7 mm gap (see previous step 11) ensures that with the bellows seal fitted
there is just a slight gap between it and the diaphragm whilst in its neutral position.

IM-P006-07 CTLS Issue 12 19
0.7 mm
(0.028")
Straight edge Straight edge
Fig. 8
12. After locating the bellows seal assembly carefully over the plunger and tighten down to a torque of
115 N m.
13. Check with straight edge again, that with the top of the bellows pressed lightly onto the top of the plunger,
there is a slight clearance - a mere line of light between the straight edge and the top of the bellows (see
Figure 8).
14. Before reassembling the valve make sure that the gasket faces on both the pilot valve block and the
body are clean and that the main valve spring (16) is positioned correctly on top of the main valve head.
15. Fit new gasket (15) and secure the pilot valve block assembly onto the body with the nuts (11). Tighten
these nuts to the torques shown in Table 1, page 20.
16. Refit the 6 mm stainless steel pipework and retighten the union nuts to ensure a steam tight seal.
17. Refit the two diaphragms (9) making sure that they are fitted the same way round as they were removed
and that all contact surfaces are clean. If necessary two new diaphragms can be fitted.
18. Place the bottom spring plate (7) in position and secure the spring housing with the 4 x M10 nuts (8)
tightening to a torque of 50 N m.
19. Replace the spring (6) and the top spring plate (5) turning the adjustment screw (1) until it just locates
on the top spring plate. Replace the cover (12) and the 'C' washer (3).
20. Bring the valve back into commission by following as many steps as are necessary in Section 4.1,
'Start-up'.
Table 1
Recommended tightening torques for the pilot valve block securing nuts item (21)
Size of valve Nut size Tightening torque
DN15LC, DN15 and DN20 M10 40 N m
DN25 to DN50 M12 60 N m
Note: for DN40 and DN50 valves predating 1996: M16 110 N m
DN80 M12 80 N m

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20
11
14
13C
13D
13A
13B
Fig. 9
5.6 How to clean the pilot valve strainer screen
1. Isolate the reducing valve and zero the pressure.
2. Release the lock-nut (2) and turn the adjustment screw (1) anticlockwise until the spring is slack.
3. Undo the union nuts and release the 6 mm stainless steel pipework.
4. Undo the nuts (21) and remove the pilot valve housing (10) complete with the spring housing assembly,
making sure that the main valve spring (16) is positioned correctly on top of the main valve head (17).
5. Holding the pilot valve block upside down, unscrew the screen retaining nut using a 27 mm A/F spanner.
6. Remove the screen (14) for cleaning, taking care not to lose the small return spring (13D) and ball (13C)
which can also be cleaned if necessary.
7. Refit the ball, spring and screen and refit the screen retaining nut (13B), tightening it to a torque of 15
N m.
8. Make sure that the gasket faces on both the pilot valve block and the body are clean. Make sure that the
main valve spring (16) is positioned correctly on top of the main valve head (17).
9. Fit new gasket (15) and secure the pilot valve block assembly onto the body with the nuts (21). Tighten
these nuts to the torque shown in Table 1.
10. Refit the 6 mm stainless steel pipework and retighten the union nuts to ensure a steam tight seal.
11. Bring the valve back into commission by following as many steps are as necessary in Section 4.1, 'Start-
up'.
Fig. 10