Courses
G3 Unvented Hot Water Systems

G3 Unvented Hot Water Systems

Become certified to legally install, service, and commission unvented hot water systems.

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Duration:

1 day

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Schedule:

Weekdays only

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Class size:

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Location:

Southampton, SO15 0HW

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Learning format:

In-person (theory & practical)

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Qualification gained:

G3 Unvented Hot Water Systems

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Awarding body:

Cert-ain

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Finance available:

No

£
220

total course cost

Finance is available to split the cost, securing your place with a £1000 deposit.

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Next start date:

29 Jan 2026

This package follows the scheduled dates of the Diploma in Plumbing & Heating Level 2, G3 Unvented Hot Water, and Water Regulations courses. Please check each course page for the next available start dates.

Spaces available

Upcoming dates:

26 Feb 2026, 26 March 2026, 30 April 2026, 28 May 2026

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The G3 Unvented Hot Water Systems course is aimed at qualified plumbers and heating engineers who want to legally install, service, and commission domestic unvented hot water systems in the UK. The course combines practical training with detailed theory covering system design, safety devices, compliance with Part G3 of the Building Regulations, and commissioning procedures. It is ideal for professionals seeking certification to demonstrate competence and increase employability in the plumbing and heating sector.

What you'll learn

A focused mix of theory and practical training covering the legal, design, installation and safety requirements for unvented hot water systems, including:

  • Types and configurations of vented and unvented hot water systems
  • Design and installation requirements for domestic hot water systems
  • Safety devices, controls and discharge pipework
  • Commissioning, servicing and fault diagnosis
  • Compliance with Building Regulations Approved Document G (Part G3)
  • Water Supply (Water Fittings) Regulations 1999
  • Correct operation of specialist components (PRVs, expansion vessels, tundishes, valves)

How you'll learn

  • Tutor-led classroom theory sessions
  • Practical, hands-on training on unvented hot water systems
  • Guidance based on industry regulations and manufacturer requirements
  • Assessment preparation built into the course delivery

Additional information

Who is this course for?
  • Qualified plumbers wanting G3 certification
  • Heating engineers installing or servicing unvented systems
  • Engineers who need legal compliance to work on unvented hot water systems
Entry requirements
  • Must hold a Level 2 qualification in Plumbing (or equivalent)
  • Relevant industry experience recommended
What's included
What you'll need to attend
Health & safety information
How you'll be assessed
  • Theory Exam: Multiple-choice test covering unvented system design, safety devices, regulations, and commissioning procedures.
    • Pass rate: 100%
    • Up to 3 attempts allowed.
    • Oral questioning may follow the second attempt if 80%+ is achieved.
  • Practical Assessment: Installation, servicing, and commissioning of unvented hot water systems in line with Part G3 of the Building Regulations.
  • Retakes: Candidates who do not achieve the pass mark must retake the assessment.

Certificate:
Successful candidates receive a Cert-ain G3 Unvented Hot Water Systems Certificate of Competence and a photo ID card, recognised by Gas Safe and OFTEC.

Career options
  • Recognition as a competent unvented hot water installer
  • Ability to legally install, service and commission unvented systems
  • Enhanced employability within plumbing and heating roles
Course fees & payment options

The total cost of the course is £220, payable in full and inclusive of VAT.

Support

FAQs

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Our team is happy to help. Get in touch and we’ll answer your questions and help you choose the right course for you.
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Will this course help me get work?

Yes, completing this course demonstrates your competence in unvented hot water systems, helping you meet industry regulations and increase employability.

Is this course recognised by industry bodies?
  • Yes, the qualification is recognised by Gas Safe Register and OFTEC, confirming your competence in unvented hot water systems.
    • Do I need to bring anything to the course?
  • You do not need to bring tools, but bring any ID required for certification and ensure you have suitable workwear for practical training.
    • Can I retake the course if I fail?
  • Yes, you can retake both theory and practical assessments after feedback and further tuition.
    • What certification will I receive?
  • Successful candidates receive a Cert-ain G3 Unvented Hot Water Systems Certificate of Competence and a photo ID card, recognised by Gas Safe and OFTEC.
    • What is the pass mark for the course?
  • You must achieve 100% to pass. If you do not pass on the first attempt, you are allowed up to 3 attempts. Oral questioning may be used if you achieve 80–99% on your second attempt.
    • How will I be assessed?
  • Assessment includes a multiple-choice theory exam and a practical assessment on unvented hot water systems.
    • How long is the course?
  • This is a one-day course with both theory and practical training included.
    • Do I need any qualifications to attend?
  • Yes, you must hold a Level 2 qualification in plumbing or an equivalent domestic heating qualification.
    • Who is this course for?
  • Plumbers and heating engineers who want to legally install, service, or commission domestic unvented hot water systems in the UK.

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