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Completion earns a downloadable certificate.
Course led by : OTAC
Vented & Unvented Hot Water Systems (G3)
Understand pressurised hot water principles, mandatory safety controls, and G3 compliance.
Unvented hot water systems operate under pressure and require strict safety controls to prevent system failure. Developed in line with Building Regulations Approved Document G3 and UK awarding standards, this CPD-accredited online course equips plumbing professionals, maintenance teams, landlords, and building managers with essential knowledge on system design, mandatory safety devices, and regulatory responsibilities.
100% Online & CPD Accredited
Approved Document G3 Aligned
Essential Foundation for Practical G3
Instant Digital Certificate
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WHAT YOU WILL LEARN
Learners will gain a solid understanding of:
✅ Building Regulations Approved Document G3 requirements for safe system design and operation
✅ Operating principles of pressurised, unvented domestic hot water systems versus traditional vented systems
✅ Mandatory safety devices, including expansion vessels, temperature relief valves, and pressure relief valves
✅ Discharge pipework rules and correct tundish arrangements for safe pressure release
✅ Common system faults, inspection considerations, and diagnosing overpressurisation issues
✅ Legal duties & responsibilities for installers, maintenance technicians, landlords, and duty holders
✅ Emergency procedures and safe protocols during system malfunction or thermal expansion risks
✅ Underpinning knowledge that serves as a strong foundation for practical G3 centre assessment
✅ Legal duties & requirements under the Control of Substances Hazardous to Health Regulations 2002
✅ Substances covered by COSHH vs. excluded materials (asbestos, lead, radioactive substances)
✅ Routes of exposure: inhalation, skin absorption, ingestion, and injection
✅ GB CLP hazard pictograms, signal words, and interpreting Safety Data Sheets (SDS)
✅ Workplace Exposure Limits (WELs) and navigating HSE publication EH40
✅ The 8-step COSHH assessment process and workplace exposure evaluation
✅ The hierarchy of controls: elimination, substitution, engineering controls, and PPE as a last resort
✅ Health surveillance duties, safe storage, handling, disposal, and emergency spillage procedures
COURSE AT A GLANCE
[1] 100% Online Theory – Self-paced interactive learning accessible on any desktop or mobile device
[2] Instant Certification – Download your digital CPD certificate immediately upon passing
[3] Statutory Alignment – Aligned with Approved Document G3, PUWER 1998, and HSW Act 1974
[4] Critical Safety Knowledge – Master the essential mechanics of high-pressure thermal equipment
[5] Practical Prerequisite – Build the required underpinning knowledge before hands-on centre assessment
[6] Universal Relevance – Essential for plumbers, maintenance staff, housing officers, and facility managers
Fast, flexible, and fully accredited online learning
More details about this course
Vented and Unvented Hot Water systems G3 Course Overview The Unvented Hot Water Systems (G3) Awareness Course provides learners with a comprehensive understanding of the design, operation, and safety requirements of unvented domestic hot water systems. Developed in line with Building Regulations – Approved Document G3, this course reflects the standards expected by UK awarding bodies and supports safe working practices across the plumbing and heating industry. This online training programme explains the principles of pressurised hot water systems, the essential safety components, and the legal responsibilities placed upon installers, maintenance personnel, duty holders, and building managers. While this is an awarenesslevel programme and does not qualify learners to install or certify unvented systems, it forms a strong foundation for CPD and further practical G3 qualification. This course aligns with key UK legislation, safety standards, and technical guidance governing the installation and operation of unvented hot water systems: Building Regulations – Approved Document G3 Specifies legal requirements for the safe installation, operation, and maintenance of hot water systems Outlines mandatory safety devices: Temperature and pressure relief valves Expansion vessels Tundish and discharge pipework requirements Requires that unvented systems are installed and serviced by competent and appropriately certified individuals Health and Safety at Work etc. Act 1974 Places duties on employers to ensure safe systems of work Requires adequate training for employees working with pressurised equipment Provision and Use of Work Equipment Regulations (PUWER) 1998 Requires equipment to be maintained in a safe condition Applies to workers servicing or inspecting unvented systems Building Services Compliance Guides & Manufacturer Standards Reinforce the need for correct installation, annual servicing, and adherence to manufacturer instructions This training supports compliance with the above regulations and prepares learners for practical G3 competence courses where required. Course Overview Learners will develop a strong awareness-level understanding of: The principles and operation of unvented hot water systems Key safety components and why they are required under G3 Safe discharge pipework arrangements and tundish requirements Common faults, system failures, and inspection considerations Responsibilities of installers, landlords, and duty holders Correct procedures in the event of system malfunction or overpressurisation This structured learning supports safe working practices and provides essential underpinning knowledge for more advanced practical training. (Please note: Practical competency certification must be completed through an approved G3 assessment centre).
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