Spirax Sarco 25P User Manual

Type 25P & 25PA Pressure Reducing Valves
INSTALLATION AND MAINTENANCE INSTRUCTIONS
IM-3-000-US January 2018
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.
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.

Spirax Sarco 25P Specifications

General

Action	Direct acting
Operating Temperature	-10°C to +80°C (14°F to 176°F)
Ambient Temperature	-20°C to +60°C (-4°F to 140°F)
Type	Pneumatic valve positioner
Materials	Stainless steel

Summary

Safety Information

Intended Use and Suitability

Confirms product suitability for intended application, fluids, materials, and operating limits.

Safe Access and Lighting

Ensures safe working conditions including access, platforms, and adequate lighting.

Hazardous Environment Considerations

Addresses risks from pipeline contents and surrounding hazardous environments.

System and Pressure Safety

Considers system impact, pressure isolation, and safe venting procedures.

Tools, Consumables, and PPE

Ensures availability of correct tools, genuine parts, and appropriate protective clothing.

Work Permits and Handling

Details requirements for permits to work and safe manual handling practices.

Residual Hazards and Freezing Protection

Addresses residual hazards like hot surfaces and necessary protection against freezing.

Disposal and Product Returns

Provides guidelines for product disposal and information required for returns.

Safe Handling of Cast Iron

Safe handling procedures for cast iron products, considering its brittle nature.

Prevention of Tensile Stressing

Guidelines to prevent damage from pipe misalignment during installation.

Prevention of Water Hammer

Methods to prevent water hammer, including steam trapping on steam mains.

Installation Procedures

Unpacking and Piping Preparation

Instructions for careful unpacking and preparing piping for valve installation.

Piping Guidelines

Recommendations for upstream/downstream piping, swage nipples, and flow direction.

Assembly and Connections

Steps for assembling the pilot to the valve body and connecting the pressure sensing line.

System Components and Recommendations

Guidance on bypass connections, drain traps, strainers, stop valves, and separators.

Remote Operation Hook-up

Diagram and instructions for remote operation setup of the 25 PRM valve.

Valve Operational Principles

Explanation of how the 25P and 25PA pressure reducing valves function.

Start-up Sequence

Step-by-step instructions for the initial start-up of the pressure reducing valve.

Troubleshooting Common Issues

Pressure Overshoot Problems

Diagnosing and resolving pressure overshoots under normal and light load conditions.

Valve Fails to Open

Identifying causes and cures for the valve not opening, including diaphragm and orifice issues.

Low Delivery Pressure

Troubleshooting insufficient delivery pressure, considering valve undersizing and supply pressure.

Valve Fails to Close

Addressing issues where the valve does not shut off properly, including bypass leaks.

Maintenance and Servicing

General Inspection Checklist

Routine checks for strainers, valve seats, orifices, and joints for leaks.

Servicing Procedure and Diagnosis

Steps to diagnose valve malfunctions by checking pilot valve and main valve seating.

Pilot Valve Component Service

Procedures for inspecting and replacing pilot valve head, seat, and diaphragms.

Main Valve Head and Seat Service

Instructions for inspecting and replacing the main valve head and seat for 1/2"-4" sizes.

Main Valve Diaphragm Service

Procedures for inspecting and replacing main valve diaphragms for 1/2"-4" and 6" sizes.

Main Valve Head and Seat Servicing (6" Valve)

Specific steps for servicing the main valve head and seat on 6" size valves.

Spare Parts Information

Main Valve Spare Parts Listing

Lists main valve components and part identifiers for different valve size ranges.

Spares Kits for Maintenance

Details on recommended spares kits for general maintenance purposes.

Piping Sizing Guide

Steam Velocity Principles

Explains how steam expands and increases velocity across reducing valve seats.

Steam Velocity Chart Usage

Guidance on using the chart to determine suitable pipe sizes for steam capacities.

Piping Sizing Example

Demonstrates finding optimal upstream and downstream pipe sizes using the velocity chart.