Switch to mobile site

Unvented Hot Water Storage System

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

Create an Article

Types of Unvented Systems

Storage Heaters (over 15L)

Directly Heated

  • Unvented systems are operating at a pressure of usually between 2 bar and 3.5 bar
  • MIN 2 temperature activated safety devices (operating in sequence)
    • Non-self resetting thermal cut-out (BS 3955 or BS 4201)
    • Temperature relief valve (BS 6283: Part 2 or 3)
  • Overheat Thermostat alongside the normal control thermostat
< Go Back2014-04-06

Indirectly Heated

  • Water in a cylinder is heated through a coil inserted inside the cylinder
    • all the controls listed for a direct system
    • plus Control Thermostat with ECO at 65°C
  • Any <500L and <45kW should be in the form of Unit or Package
< Go Back2014-04-06