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Domestic Hot Water

Exam revision materials for Plumbing Level 2&3 and ACS Gas Safety test

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  • Copper [BS EN 1057] Table X
    • Copper is susceptible to corrosion when directly contacted with Galvanised LCS
    • Grade 3
  • Galvanised LCS
  • Polybutylene
  • Chlorinated Polyvinyl-chloride (cPVC)
  • uPVC (unplasticized) for cold water (brittle above 20°C)
  • Cross-linked polyethylene (PE-X) – under-floor heating (tends to sag)

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Thermal Movement Allowance

  • Gland expansion joints
  • Expansion loops
  • Horseshoe expansion loops
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Trace Heating

  • frost and dead legs protection for industrial
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Hydrauling Gradient

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Secondary Circulation

Secondary Circulation
  • Return to 1/3 from the top of the vessel
  • Bronze Pump MUST be used to avoid the pump rusting
  • MIN return temperature is 50°C
  • Controlled by a Time Switch
  • MAX Length of HW pipework without secondary return
    • ≤22mm – 12m
    • ≤28 mm – 7.5m
    • >28mm – 3m
    • MAX 30 sec for HW to reach a tap
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