Water Supply Industry Interpretations and Advice

  • Area of Interest : Installation
  • Topic : Water heaters - expansion water
  • Title : Isolation valves in expansion vessel pipework.
  • Clause Reference : Regulation 3(2) (i) & Schedule 2 paragraph 11
  • Reference Number : I07
  • Decision Date : February 2002 (Revised March 2013)

In recognition that the need to carry out maintenance should take into consideration the requirement not to waste water, the installation of servicing valves on the pipework connecting an expansion vessel to an unvented water heater is permitted.

It is however recommended that these servicing valves be of a tamperproof design, such as a ‘lockshield’ valve.