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Domestic Hot Water

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

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Hot Water Systems

Vented Systems

Indirect Hot Water System

Indirect Hot Water System

  • preferred over direct for hard water
  • it is permissible to use Cast Iron Heat Exchanger
  • Single-feed System (not widely used)
    • uses self-venting cylinder
    • does not require F&E Tank
    • the primary and secondary circuits are separated by an Air Bubble
    • use of chemical inhibitor is NOT allowed!
< Go Back2013-04-14

Direct Hot Water System

Vent Pipe

  • removes air from the system
  • maintains atmospheric pressure in the system
  • Air Release Valve is fitted if the Vent Pipe is not connected to the highest point
  • MIN 450mm from point of delivery to a connection point - to avoid one pipe circulation
  • MIN 22mm in size
  • Hight of the Open Vent (mm) = 150 + 4 x (head in m)
< Go Back2013-04-14