Spirax Sarco DP27T User manual

IM-P240-02-EN-ISS1 CTLS 1
DP27T
DP27TE
1. Safety information
2. General product
information
3. Installation
4. Commissioning
5. Maintenance
6. Spare parts
7. Fault finding
4701036/3
DP27T and DP27TE
Pilot Operated Pressure/Temperature
Control Valves
Installation and Maintenance Instructions
PREVIOUS REFERENCE NO. IM-P470-09
© Copyright 2018
Printed in GB
IM-P240-02-EN-ISS1
CTLS

IM-P240-02-EN-ISS1 CTLS2

IM-P240-02-EN-ISS1 CTLS 3
1. Safety information
Safe operation of these products can only be guaranteed if they are properly
installed, commissioned, used and maintained by suitably 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 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
DP27T and DP27TE
DN15 - DN40 SEP
DN50 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.

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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.
PTFE:
-Can only be disposed of by approved methods, not incineration.
-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, 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.

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2. General product information
2.1 General description
The DP27T and DP27TE are combined pressure / temperature control valves for use on
steam applications. They are designed to be used in conjunction with a 2 m length of
capillary which is available separately (other lengths available on request). They combine
a temperature and pressure pilot valve in one unit. This controls the main valve so that the
temperature is maintained while the maximum steam pressure is limited.
A variable rate conical pressure adjustment spring is fitted providing a downstream pressure
range of 0.2 - 17 bar g.
Notes: 1. The sensor of the control system will need to be mounted by either a union kit,
pocket or wall mounting bracket.
2. For additional information see the relevant Technical Information Sheet.
Available types of valve:
DP27T Pressure/temperature control
DP27TE Pressure/temperature control with electrically operated solenoid valve
2.2 Sizes and pipe connections
Screwed BSP (BS 21 parallel) or NPT (½" to 1" only).
Flanged DN15LC - Low Capacity version, DN15, DN20, DN25, DN32, DN40 and DN50.
Flanges:
Standard
DN15 - DN50 EN 1092 PN25
DN25 - DN50 BS 10 Table H and ASME (ANSI) 300
Available on request:
DN15 - DN50 JIS 10, JIS 16 and ASME (ANSI) 150
DN15 - DN20 BS 10 Table F
DN15 ASME (ANSI) 300
Note: For additional information see the relevant Technical Information Sheet.

IM-P240-02-EN-ISS1 CTLS 7
DP27TE
DP27T Temperature ranges
Range A 16 °C to 49 °C
Range B 38 °C to 71 °C
Range C 49 °C to 82 °C
Range D 71 °C to 104 °C
Range E 93 °C to 127 °C

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2.3 Pressure / temperature limits
0
0
50
100
150
200
190
232
5 10 15 17.2 20 25
Pressure bar g
Temperature °C
A
E
Steam
saturation
curve
C
B
D
G
G
The product must not be used in this region.
A-D-E Screwed and flanged EN 1092 PN25, ASME (ANSI 300), and BS 10 Table H.
A-B-C Flanged ASME (ANSI) 150.
G-G The DP27TE is limited to 10 bar g @ 190 °C.
Body design conditions PN25
Maximum design pressure
A-D-E 25 bar g @ 120 °C
A-B-C 17.2 bar g @ 40 °C
Maximum design temperature 232 °C @ 21 bar g
Minimum design temperature -10 °C
Maximum upstream pressure for saturated steam service
DP27T 17 bar g
DP27TE 10 bar g
Maximum operating temperature
DP27T 232 °C @ 21 bar g
DP27TE 190 °C @ 10 bar g
Minimum operating temperature
Note: For lower operating temperatures consult Spirax Sarco.
0°C
Maximum differential pressure
DP27T 17 bar
DP27TE 17 bar
Designed for a maximum cold hydraulic test pressure of: 38 bar g
Note: With internals fitted, test pressure must not exceed: 25 bar g

IM-P240-02-EN-ISS1 CTLS 9
DP27T
DP27TE
Fig. 1
Control head securing screws
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.
The installation instructions are dealt with under two headings, 'The valve' and 'The
temperature control system'.

IM-P240-02-EN-ISS1 CTLS10
3.1 Supply (Figure 1)
DP27T
The DP27T pressure/temperature control is supplied with the temperature control unit
packed separately and should be assembled securing the control head to the valve by
means of the three screws supplied.
The valve is fitted with a control spring most suited to the downstream pressure condition
quoted on the order, but will not be pre-set.
The temperature control unit is fitted with a control system having a range most suited to
the temperature given on the order but it is not pre-set.
DP27TE
The DP27TE pressure/temperature control is supplied as for the DP27T but a solenoid
operated valve is fitted in the pipe between the pilot valve and the main diaphragm chamber,
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 such as a thermostat, pressure switch or time clock. A suitable time
clock is available from Spirax Sarco.
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. The standard unit is
suitable for 230 ±10%Vac or 115 ±10% Vac 50 Hz supply, but units for other ac voltages
may be supplied to special order, 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. Remember that the valve is on a steam
supply line and in use will get hot. All wiring, connectors, etc. in close proximity to the valve
should therefore be of heat resisting type.
Earth
The solenoid valve should be adequately earthed.

IM-P240-02-EN-ISS1 CTLS 11
DP27T
DP27TE
Fig. 2
Control head securing screws

IM-P240-02-EN-ISS1 CTLS12
Fig. 2 Recommended installation
Alternative arrangement using
equal tee for drainage
3.2 The valve
General arrangement
Figure 2 shows the recommended installation layout to ensure satisfactory operation of the
DP27T pressure/temperature control. It should always be fitted in a horizontal pipeline with
the main diaphragm chamber below the line.
Pressure sensing pipe
(see Section 3.8)
Bypass valve
(see Section 3.10)
1 m or 15 pipe diameters clear
on either side (see Section 3.8)
Strainer with
blowdown
cock
DP27T pressure/
temperature regulator
Strainer
Steam trap
Sight
glass
Upstream
pressure
gauge
Downstream
pressure
gauge
Pressure control
stop valve
Safety
valve
Fullway
valve
Separator
(see Section 3.6)
Sight glass
Strainer
Fullway valve
Strainer with
blowdown cock
Steam trap
(see Section 3.6)
Steam
Condensate
Fall
Steam
Condensate


IM-P240-02-EN-ISS1 CTLS 13
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 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 the steam is known to be
dry then a drain pocket may be adequate.
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.
3.7 Preventing 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.
3.8 Pressure control pipe
The valve will be supplied complete with a balance pipe assembly connecting the side of
the body with the side of the pilot valve chamber.
When close control of pressure and/or maximum capacity is required, an external pressure
sensing pipe must be fitted.
To fit this alternative downstream sensing pipe, first 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
and a spare pilot filter). The other " BSP fitting in the side of the pilot valve chamber 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 downstream pressure sensing pipe (not supplied) 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
DP27T. 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. A stop valve should be fitted for isolating purposes.
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 can also be useful.

IM-P240-02-EN-ISS1 CTLS14
3.10 Bypass
If it is essential to maintain a constant supply of steam and the reducing valve station does
not include duplication or stand-by equipment, it may be necessary to install a bypass to
ensure continuation of supply when the reducing valve is being serviced (see Figure 2).
The bypass valve will normally be the same size as the reducing valve. The handwheel
should be padlocked to prevent use by unauthorised personnel, 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.
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 build up on the downstream
side of the DP.
D
C
B
A
A
Fig. 3 DP position
in relation to other
control equipment

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3.13 Temperature ranges
The temperature control system is available
in five temperature ranges as follows:-
Range A 16 °C to 49 °C
Range B 38 °C to 71 °C
Range C 49 °C to 82 °C
Range D 71 °C to 104°C
Range E 93 °C to 127 °C
3.14 Sensor bulb
The type DP27T control is fitted with a
plain bulb as in Figure 4, but as an optional
extra this bulb is supplied with an adaptor
shown in Figure 5, consisting of a union
nipple (U), 'O' ring (V) and gland nut (W).
3.15 Use of plain bulb
Where it is desired to use a plain bulb as in
Figure 4 the adaptor can be removed by
unscrewing the gland nut (W) from the
union nipple (Figure 5) and withdrawing
each piece of the assembly separately over
the bulb.
3.16 Use of immersion bulb
Where it is desired, insert the bulb into a
vessel under pressure. Unscrew the gland
nut (W) from the union nipple (U). This will
enable the union nipple to withdraw over the
bulb. The union nipple can now be screwed
into the tapping provided at the temperature
sensing point.
The union nipple is normally threaded ¾"
BSP but may be ¾" NPT if specially
ordered.
Insert the bulb through the union nipple (U)
until the 'O' ring (V) seats in the union nipple
as shown in Figure 5 and screw home the
gland nut (W) to compress the 'O' ring. The
gland nut needs to be little more than
finger tight. Do not overtighten
otherwise damage to the 'O' ring will
result.
W
V
¾" BSP taper
NPT available
Level
of
fluid
Fig. 7
W
V
U
Fig. 5
¾" BSP taper
NPT available
Fig. 4

Fig. 6

IM-P240-02-EN-ISS1 CTLS16
3.17 Pockets
In all cases where the temperature sensing point is in a fluid under pressure it is best to
use a pocket so that the bulb can be withdrawn for servicing without draining down the
plant.
Pockets must also be used where the medium being controlled would attack and destroy
the material from which the bulb is constructed.
The top of the pocket is formed exactly as the union nipple and should be screwed into the
tapping (¾" BSP or ¾" NPT) provided at the temperature sensing point.
Insert the bulb into the pocket until the 'O' ring seats in the union nipple as Figure 6, and
screw home the gland nut (W) to compress the 'O' ring.
The gland nut (W) will be little more than finger tight. Do not overtighten otherwise
damage to the 'O' ring will result.
3.18 Extra long pockets
Where extra long pockets are used the plain bulb
should be used and inserted the full length of the
pocket.
A split bung is provided to seal the top of the pocket
Fi gu re 7.
3.19 Heat conduction
Where a bulb is used in a pocket the pocket should
be filled with a heat conducting fluid, such as thin oil
or water, to improve heat transfer.
Do not fill the extended pocket Figure 7, above the
level of the bulb.
3.20 Wall mounting sensor
Where the type DP27T control is to be used to control
from room temperature the plain bulb Figure 4 is used
and a bracket and protective shield is provided Figure
8.
It is essential that the sensor be fitted in such a
position that it can sense the true room temperature
and is not influenced by draughts.
It is preferably fitted in the vertical position and can
be fitted either with the capillary leading from the top
of the sensor or leading from the bottom.
Having decided on the sensor position fix the bracket
to the wall making sure that it is fitted in such a way
that the lug standing proud of the base will engage
with the groove turned in the sensor.
After inserting the sensor in the clips, fit the external
cover as in Figure 9.
Fig. 8
Fig. 9

IM-P240-02-EN-ISS1 CTLS 17
Fig. 8
Fig. 9
4. Commissioning
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.
When the pressure/temperature control is installed and all connections are properly made
it must be brought into operation in two stages a) Pressure reduction. b) Temperature
control.
4.1 To set the reduced pressure
1. Ensure that all connections are properly made and that all valves are closed.
2. Check that 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. 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. Slowly open the downstream valve until it is fully open.
7. Using a 19 mm A/F spanner slowly turn adjustment screw in a clockwise direction until
desired 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.

IM-P240-02-EN-ISS1 CTLS18
4.2 To set the temperature
1. Check that the temperature scale can be easily seen.
If it is fitted in a confined space facing a wall for example the control head may be
repositioned to enable the scale to be more easily read as follows:-
Undo the three screws. The control head may now be turned through 120°or 240°and
the screws tightened up.
2. By turning the knurled knob, set the scale opposite the pointer to the temperature at
which it is desired to control. (Where it is essential that this temperature be not exceeded
it is advisable to set the control initially some 6 °C lower and bring the plant up to
temperature slowly).
3. Put the plant in operation in the normal way allow 30 minutes for it to settle down, then
check the temperature against a reliable thermometer - this check reading should be
taken as close to the control point as possible to ensure that both the thermometer and
the sensor bulb are sensing similar conditions.
4. Compare the thermometer reading with scale reading on the temperature control.
5. This may be found to differ by a few degrees and if precise control is required can be
adjusted by resetting the pointer as follows:
6. Holding the control head tightly onto the pilot valve housing - slacken the three screws,
just sufficiently to enable the pointer to be moved to the right or left until the temperature
indicated on the scale corresponds with the actual temperature as shown on the sensor.
Whilst making this adjustment it is essential to hold the control head tightly onto the
pilot valve housing otherwise not only will movement of the pointer be difficult but
allowing the head to lift will open the pilot valve.
7. Tighten the three screws.
8. The adjustment knob may now be reset to the required temperature. Adjustments to
raise or lower the temperature may be freely made without damage to the control system.

IM-P240-02-EN-ISS1 CTLS 19
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 parts that may require replacing or refurbishing are listed below:
- Pilot filter element (Section 5.2).
- Pressure adjustment spring (Section 5.3).
- Pressure control pilot valve assembly (Section 5.4).
- Strainer screen (Section 5.5).
- Pilot valve diaphragms (Section 5.6).
- Main diaphragms (Section 5.7).
- Main valve and seat (Section 5.8).
- Temperature control pilot valve assembly (Section 5.9).
- Temperature control system (Section 5.10).
- Solenoid valve - DP27TE only (Section 5.11).
Strainer screen
Temperature
control pilot
valve assembly
Temperature
control system
Main diaphragms
Main valve and seat
Pilot valve diaphragms
Pressure control pilot valve assembly
Pressure adjustment spring
Pilot filter element
(cannot be shown in this view)


IM-P240-02-EN-ISS1 CTLS20
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:
4. Isolate the reducing valve, zero the pressure and release the adjustment lock-nut.
5. Turn the adjustment screw anticlockwise. Ensure there is no compression on the pressure
adjustment spring.
6. Undo the 4 off spring housing securing nuts and remove the spring housing.
7. Remove the pressure adjustment spring and the top spring plate.
8. Reassemble in reverse order.
4
5
7