The Copper Connection Podcast – Season 2, Episode 76, Water In, Waste Out — Cold Water Systems & Sanitary Appliances for Plumbing Apprentices | Unit 307 Phase 2
Phase 2 of your plumbing apprenticeship is where theory meets real installations. And cold water systems are where a lot of learners either click — or come unstuck.
In this episode, host Chris Bailey takes you through the complete cold water systems and sanitary appliances content for Unit 307 of the 9289 City & Guilds Level 3 Diploma in Plumbing and Domestic Heating.
This is Session 1 of the Phase 2 Unit 307 deep-dive — and it starts with a question every apprentice should be able to answer: what's the actual difference between a direct and indirect cold water system, and why does it change every installation decision you make?
Chris covers:
✅ Direct cold water systems — how they work, pressure, pipe sizes, advantages and disadvantages
✅ Indirect cold water systems — CWSC capacity, pipe sizes (including the 22mm bath feed rule), pros and cons
✅ Hard water and water treatment — magnetic conditioners, water softeners, drinking water filters
✅ Sanitary appliance materials — vitreous china, acrylic, stainless steel, fireclay, cast iron, pressed steel
✅ Baths — all six types, BS 4304, AUK2 air gap, 22mm feeds, 40mm waste, combination waste fittings
✅ Shower trays and cubicles — wet rooms, unslotted waste, feed pipe sizing
✅ WCs — washdown, siphonic, close-coupled to wall-hung, flush volumes from 9L to today's 4/6L dual flush
✅ Urinals — bowl, trough, slab, sparge pipe, automatic flushing cisterns, waterless urinals, Water Regs volumes
✅ Bidets — over-rim vs ascending spray, the AUK2 air gap rule, why ascending spray MUST be cistern-fed
✅ Valves — stop valves, gate valves, FOVs (BS 1212 Parts 1–4), drain-off valves, spherical plug valves
✅ Building Regulations Part G — 125 litres per person per day, water efficiency calculations
This episode is essential listening for:
— Plumbing apprentices on the ST0303 Level 3 standard working through Phase 2
— Level 2 Plumbing students progressing to Level 3
— T-Level Building Services Engineering learners (Year 1 and Year 2)
— Anyone revising for the 9289-021 Phase 2 multiple choice exam
Plain English. Real trade context. No fluff.
🔗 Handouts, worksheets, and revision resources at thecopperconnectionpodcast.co.uk
Next episode: Unit 307 Phase 2 Session 2 — Hot water systems, central heating, open-vented vs sealed pressurised systems.
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