Spirax Sarco 25T User manual

1
Type 25T Pilot Operated
Temperature Regulator
IM-1-1116-US October 2015
INSTALLATION AND MAINTENANCE INSTRUCTIONS
Safety Information
Safe operation of these products can only be guaranteed if
they are properly installed, commissioned, usedand 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.
i) The products have been specically designed for use on
steam, air or water/condensate. The products’ use on other
uids may be possible but, if this is contemplated, Spirax
Sarco should be contacted to conrm 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 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.
i v ) S p i r a x S a r c o p r o d u c t s a r e n o t i n t e n d e d t o w i t h s t a n d e x t e r n a l
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
p i p e l i n e a t s o m e 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 ,
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, re
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
c o m p l i e d w i t h . W h e r e t h e r e i s n o s u c h s y s t e m , i t i s r e c o m m e n d e d
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.
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.

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1.13 Residual hazards
I n n o r m a l u s e t h e e x t e r n a l s u r f a c e o f t h e p r o d u c t
may be very hot. If used at the maximum
permitted operating conditions the surface
temperature of some products may reach
temperatures in excess 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.
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
theprecautionstobetaken due tocontamination
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 identied as hazardous or
potentially hazardous.
1.17 Working safely with cast iron
products on steam
Cast iron products are commonly found on
steam and condensate systems. If installed
correctly using good steam engineering
practices, it is perfectly safe. However, because
of its mechanical properties, it is less forgiving
compared to other materials such as SG iron or
carbon steel. The following are the good
engineering practices required to prevent
waterhammer and ensure safe working
conditions on a steam system.
Cast Iron is a brittle
material. If the product
is dropped during
installation and there
is any risk of damage
the product should
not be used unless it
is fully inspected and
pressure tested by the
manufacturer.
Safe Handling
Steam Trap set Trap set Trap set
Steam
Gradient 1:100
Gradient 1:100
30 - 50 metre intervals
Condensate Condensate
Condensate
Prevention of water hammer
Steam trapping on steam mains:
Steam Mains - Do's and Dont's:
Steam 4
7
7
7
7
4
4
4
Prevention of tensile stressing
Pipe misalignment:
Installing products or re-assembling after maintenance:
Do not over tighten.
Use correct torque gures.
1
1
4 2
3
8
2
6
3
7
Flange bolts should be gradually tightened across
diameters to ensure even load and alignment.
7
4
5
4

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Installing the Valve
Unpack Carefully
Do not lift the regulator by the tubing or temperature pilot.
Grasp the body of the valve firmly when lifting. Do not
bend sharply or kink the flexible tubing.
Piping
1. Typical hookup sketches as shown in Figs. 1 and 2
will aid in planning a correct installation.
2. Before installing the valve, make sure the piping is free
of foreign material, scale, etc.
3. Make certain the arrow cast on regulator valve body is
pointing in the direction of flow.
4. Regulating valve should always be installed in a hori-
zontal position. (See Figs. 1 and 2.)
Bypass
1. A bypass connection, as shown in Figs. 1 and 2, is
recommended so that the valve can be serviced with-
out shutting down the equipment.
2. The bypass valve should be the same size as the tem-
perature regulating valve.
Steam Line Drain Trap
To insure proper operation of the valve and avoid pre-
mature wear, it is recommended that a steam trap be
installed on the steam supply line. (See Figs. 1 and 2.)
Pipeline Strainers
1. It is strongly recommended that strainers be installed
before the temperature regulating valve and steam
traps. (See Figs. 1 and 2.)
2. Make certain adequate clearance is provided for
screen removal and blowdown connection between
strainer and regulating valve body.
Stop Valves
All stop valves on the supply side, as well as on the down-
stream side of the temperature regulating valve, should
be of the gate type so as to insure full rated capacity and
good control.
Calibrated Adjustment Dial
Depending upon the installation, the position of the cali-
brated dial on the valve, as received, may not be easily
observed by the operating personnel. To change the cali-
brated dial position loosen hexagon nut (K) and rotate the
entire adjustment assembly to a position that can be easily
observed. Retighten hexagon nut (K).
Running Temperature
Control Valve
IMPORTANT: Step by step instructions on the following
pages should be read carefully before installing the valve.
Figure 1: Temperature Control of Warm-up and Running
Loads at Storage Tank
Figure 2: Controlling Temperature of Large Open Tank
Heated by Direct Steam Injection
Steam
Supply
Moisture
Separator
Spira-tec
Loss
Detector
Float &
Thermostatic
Steam Trap
Strainer
Strainer
Storage
Tank
Warm Up
Temperature
Control Valve
Run
Temperature
Sensor
Low
Tempera-
ture
Sensor
Thermostatic
Steam Trap
Condensate
Return Strainer
Check
Valve
Spira-tec
Loss
Detector
Moisture
Separator
Steam
Supply
Strainer
Spira-tec
Loss
Detector
Float &
Thermostatic
Steam Trap
Strainer
Pilot Operated
Temperature
Control Valve
Vacuum
Breaker
Open
Tank
Steam
Injector
Provide suitable support and protection
for capillary tubing and temperature bulbs
Thermostatic Bulb and Tubing
1. Carefully uncoil the flexible tubing avoiding sharp bends and
kinks.
2. Support flexible tubing to protect it against mechanical dam-
age.
3. Keep flexible tubing away from hot pipe lines or other hot sur-
faces.
4. Install thermostatic bulb to unit to be controlled. Make certain
that the entire bulb is exposed to the medium being con-
trolled. Accuracy of regulation depends on the bulb being
located in a representative location with adequate circulation
over it.
5. If a separable socket is used for the temperature bulb, it is
recommended that the socket be packed with a heat transfer
compound to minimize lag in response to temperature chang-
es caused by the insulating air layer between bulb and socket.
Thermal expansion:
Short
distance Fixing point
Axial movement
Axial movement
Guides
Guides
Guides
Guides
Limit rods
Limit rods
Fixing point
Medium
distance
Small
lateral
movement
Small
lateral
movement
Large
lateral
movement
Large
lateral
movement

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Thermometer
An accurate thermometer should be installed in very close
proximity to the temperature regulating bulb.
How It Works
Normal positions before startup are with the main valve
closed and the pilot valve held open by spring force.
Entering steam passes through the pilot valve into the
diaphragm chamber and also out through the control ori-
fice. As flow through the pilot valve exceeds flow through
the orifice, control pressure increases in the diaphragm
chamber and opens the main valve. As the medium being
heated approaches the pre-selected temperature, liquid
in the bulb expands through the capillary tubing into the
bellows and throttles the pilot valve (3E). Control pressure
maintained in the diaphragm chamber positions the main
valve to deliver required steam flow. When heat is not
required, the main valve closes tight to provide dead-end
shutoff. The temperature setting can be changed by turn-
ing the calibrated adjustment dial.
Start-Up
1. First make certain that all stop valves as closed.
2. Adjust the temperature pilot to the temperature
required by turning the red adjustment knob 3C.
Caution: Do not loosen Allen set-screw in the red
temperature knob.
3. Open stop valves in the following order:
a. Open stop valve ahead of steam trap on steam
supply line. This will insure condensate free
steam at the regulator inlet.
b. Open downstream stop valve.
c. Slowly open inlet stop valve.
4. After the system has stabilized itself, check thermom-
eter temperature. Readjustment of the temperature
pilot (red knob 3C) may be necessary. Note: In the
event the temperature indicated on the calibrated dial
does not agree with the thermometer, the temperature
pilot can be recalibrated to match the thermometer as
described on page 5.
5. Important–Retighten all pilot flange connections to
insure steam tight joints.
Maintenance
General Inspection
While a program of planned maintenance is always to be
recommended, the Spirax Sarco 25T temperature regu-
lator will give long and trouble-free service if correctly
selected, installed and kept reasonably free of dirt and
foreign matter. Dirt and foreign matter are most likely to
collect during installation and later trouble can be avoided
by inspecting the installation a few days later. Check the
following:
1. Clean all pipeline strainers (remove screens to clean).
2. Check the main valve seat and protective screen (1D).
3. Inspect and clean orifices (E) and (H).
4. Check all joints for leakage.
Servicing Procedure (Refer to Fig. 3 and 4)
To determine which part of a malfunctioning temperature
regulator requires maintenance, refer to the troubleshoot-
ing chart and follow this servicing procedure to check the
tightness of the seats.
1. With all stop valves closed and the valve cooled
down, remove the copper tubing from connectors (L)
and (N) for 1/2” - 2” valves, being careful not to bend
them.
2. Close the pilot valve (K) by turning the temperature
adjustment (3C) counter-clockwise until the spring is
completely compressed.
3. Stand clear of the tubing connectors and open the
inlet stop valve slightly so that a small amount of
steam reaches the valve inlet and pilot.
4. Open and close the pilot valve a few times by turning
the temperature adjustment and observe the steam
flow from tubing connectors (N) for 1/2” - 2” valves.
When the pilot valve is closed, there should be no
steam flow from the connectors; if there is some steam
flow, it indicates that the pilot valve assembly is faulty
and must be replaced.
5. With the copper tubing removed the main valve head
and seat are held closed and should not pass any
steam. Observe the downstream orifice connector (L).
Steam flow from this connector indicates that the main
valve head and seat are leaking and require servicing.
Inspecting and Replacing Pilot Valve Head
and Seat. (Refer to Figs. 3 and 4)
NOTE: Inspecting and replacing parts, if necessary, can
be done without removing the pilot from the main valve.
However, if more convenient, the entire pilot can be
removed from the main valve by removing the four pilot
flange cap screws.
Exception: To replace the seat in low pressure (5 psi and
below) 2-1/2”, 3”, and 4”valves, the entire pilot must be
removed from the main valve or mounting bracket.
1. Unscrew hexagon nut (K) and remove temperature
adjustment assembly.
2. The pilot valve head assembly (3E), which includes
the springs, Teflon seal, and valve head, can then be
withdrawn and inspected.
3. If it is found after inspection that the head is worn, the
entire assembly should be replaced.
4. The pilot valve seat can be removed for inspection
using a 1/2” hexagon socket wrench.
5. If the seat shows signs of wear, the seat should be
replaced including a new seat gasket.
Valve Sizes 1/2” Thru 4”
Inspecting and Replacing Main Valve Head
and Seat. (Refer to Figs. 3 and 4)
1. Unscrew copper tubing connection at (J) and (N).
2. Remove main valve cover cap screws (1A).
3. Remove main valve cover, strainer screen, and head
spring.
4. Head can then be removed by simply withdrawing
with a pliers or similar tool.
5. Inspection should then be made to determine if scale
or other foreign material prevented tight closure of the
head and seat. Check for body erosion at the seat
threads.
6. If it is necessary to replace the valve seat, this can be
removed from the valve body using a standard hexa-
gon socket. (Valve sizes 1/2” to 2”.) When replac-
ing the valve seat, a new gasket should be used to
insure a tight joint. 2-1/2” valves contain raised lugs
for removal and seal metal-to-metal without a gasket.
Replacement heads and seats should be lapped in.

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Valve Sizes 1/2” Thru 4”
Inspecting and Replacing Main Valve
Diaphragms. (Refer to Figs. 3 and 4)
1. Unscrew copper tubing connection (G).
2. Remove main valve diaphragm bolts (1C).
3. This will allow the lower diaphragm case to be removed.
4. The 2 metal diaphragms (1H) should be inspected to
insure that they have not become distorted or possi-
bly fractured as a result of abnormal operating condi-
tions.
5. At the same time any accumulation of dirt of foreign
material should be removed from the diaphragm case.
6. The valve stem (1F) should also be checked to make
sure it is free to move and that there is no scale or for-
eign material lodged in the guide bushing.
7. Before reassembling diaphragms, main valve head
must be in place and held in closed position with
the return spring and main valve cover.
8. Make certain pressure plate (1G) is set properly.
(Refer to Fig. 5)
9. Care should be taken in centering the diaphragms
properly and equalizing bolt take-up uniformly.
Size 1/2” & 3/4” 1” 1-1/4” & 1-1/2 2” 2-1/2” 3” 4”
Dim A 1/16” 5/64 3/32” 1/8” 13/64” 13/64” 1/4”
Head on Seat
Adjustment
& Locknut
Pressure Plate
1G
Figure 5
NOTE: IN 1/2” thru 4” sizes, top of valve must be com-
pletely assembled and head must be on seat when
measuring dimensions “A” and when reassembling
diaphragms.

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Troubleshooting
Type 25T
Symptom Cause Check and Cure
1. Controlled temperature 1. (a) Control not set properly; or may have been 1. (a) Readjust temperature knob (3C).
overrides set point. tampered with.
(B) Temperature bulb not in representative (b) Check actual temperature at bulb with glass
location . thermometer. If necessary, relocate bulb.
(c) Dirt under pilot valve head or pilot valve (c) Remove and, if necessary, replace or clean.
spindle (3E) sticking.
(d) Valve oversized. (d) Check actual load against valve rating.
(e) Dirt in orifices (E) or (H). (e) Inspect and clean.
(f) Dirt or foreign material under main valve (f) Set temperature knob (3C) to lowest
head (1E). Seat worn, body casting temperature. Disconnect tubing at (G).
eroded at seat threads. Valve should close. If not, remove bolts
(1A) and clean or repair main valve.
(g) Defective thermal system. (Rare). (g) Experience over the years has shown that failure of the
thermal system (other than mechanical damage) is very
rare. Only after all of the “checks” listed on the trouble-
shooting chart have been pursued, should the follow-
ing test be made to determine if the thermal system is
defective.
i. Disconnect copper tubing connection at (J).
ii. Immerse thermal system bulb in a temperature 20°
above dial setting. Allow to saturate for approxi-
mately 5 minutes.
iii. Open steam supply stop valve to allow steam to flow
to temperature regulator.
iv. Under these conditions steam should not flow from
copper tubing connections (J) which shows that the
thermal system is satisfactory.
v. If steam should flow from tubing connection (J), exert
pressure downward with thumb on thermal system
elbow connection (3A). If this pressure seats pilot
valve head and stops steam flow, the thermal system
is probably defective.
(h) Bypass valve leaking. (h) Check and correct.
2. Temperature too low or 2. (a) Control not properly set or may have been 2. (a) Adjust temperature knob (3C) to higher setting.
valve does not open. tampered with.
(b) Thermostatic bulb not in representative (b) Check actual temperature at bulb with glass
location. thermometer. If necessary, relocate bulb.
(c) Valve undersized. (c) Check actual load against rating of valve.
(d) Main valve diaphragm (1H) cracked. (d) Remove copper tubing at (G) and crack bypass
valve. If steam blows from diaphragm case at
(G) connection, replace diaphragm.
(e) Orifice at (H) blocked. (e) Remove copper tubing at fitting. Inspect and clean.
(f) Steam pressure too low. (f) Check and correct.
(g) Valve strainer (1D) blocked. (g) Remove bolts (1A). Inspect strainer and clean.
(h) Line strainer partially or completely blocked. (h) Inspect and clean.
(i) Pilot valve spindle (3E) sticking in guide. (i) Remove thermal system by loosening nut (M). Apply
pressure to spindle, observe up and down motion. If
necessary, clean or replace spindle assembly.
(j) Steam trap draining equipment may not be (j) Check and repair, if necessary.
functioning properly.
3. Erratic control. 3. (a) Thermostatic bulb is not installed in the 3. (a) Check actual temperature at bulb with glass
proper location. thermometer. Relocate bulb, if necessary.
(b) Heating surface may be waterlogged due (b) Inspect and repair, if necessary.
to defective steam trap.
(c) Valve size may not be correct. (c) Check actual load against valve rating.

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3A
Figure 3
1/2” thru 2” Sizes
M
3C
K
3E
1H
1G
G
H
1C
E. Orifice with
Cleaning Wire
1E
N
1A
1F
1D
J
3A
3C
K
J
1D
E
1F
1G
G
H
1H
Figure 4
2-1/2” thru 4” Sizes
1C
1A
L
M
L

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SPIRAX SARCO, INC. • 1150 NORTHPOINT BLVD. • BLYTHEWOOD, SC 29016
PHONE [phone] • FAX [phone]
Spirax Sarco Applications Engineering Department
Toll Free at:
1-800-575-0394