Maintaining Process System Control Valve Assemblies

The selected 4” Globe type Pressure Control Valve and Valve Positioner must be of a similar specification and complexity of construction to that of the example show.

The Examiner should make available a range of Gland Packing Rings/Joints and Seat Joints from which the Candidate will be required to select the appropriate ones for the application.

The Examiner should make available a range of test equipment to apply a full stroke check of the valve.

The Examiner should make available a range of pressure test equipment from which the candidate will be required to select appropriate equipment to complete a 25barg body pressure test of the valve following overhaul.

The Examiner should make available to the Candidate a copy of a selection of vendor installation and commissioning manuals from which the candidate will need to select the appropriate one for the test.

Technical Assessment – The candidate is required to dismantle a fully operational 4” globe valve with the purpose to fit new seat joints and packing rings. On completion the candidate will be required to set up the valve to operate open/closed on a 4-20mA control value. The valve will also require a body pressure test to 25barg.

Objective - To ensure a candidate has the skills, knowledge and ability to overhaul a typical process control value and set up for operational conditions. The candidate will have to demonstrate they can work safely whilst overhauling the valve using appropriate methods and techniques.

Technical Assessment Requirements

Range of screwdrivers of various size and types (flat, crosshead and Phillips)
Range of spanners (open ended, combined and ring)
Range of Allen keys (Metric & Imperial)
Range of test ancillary equipment (leads, jack plugs, crocodile clips, connection blocks etc.)
Strap Wrench
Selection of hide hammers
Gland Packing Extractor tools
A variable milliamp Source and leads
Fully operational 4” Globe Valve fitted with an operational 4-20mA Valve Positioner
A selection of the valve and positioner Vendor Manuals (Installation and Commissioning)
Spare Seat and Valve Packing
Valve Test Rig or Equipment
Lifting equipment
Personal Protective Equipment
Examiner instructions
Model Answer Sheet
Candidate instructions
Instrument Test Record (ITR04)
Candidate Question Paper
Examiner Results Report

The candidate must check the general condition of the valve in addition to fitting new seat joints and valve packing rings. The candidate should report any faults to the Examiner. On completion of the overhaul and pressure test the candidate must set up the valve to operate from 0 – 100% stroke on a 4-20mA input signal.
Calibration MUST be within +/- 1.0%

The candidate is expected to complete the test whilst being observed using correct the correct tools, equipment, service supplies and established techniques, to achieve the specification. The activity must be completed using safe working practices to achieve a ‘PASS’. Where the candidate does not achieve the set criteria this is recorded as ‘REFERRED’ and a brief note recorded on the criteria not met in the test activity.

The candidate must record a PASS in all practical test sections and score a minimum of 80% in the multiple choice section.