# The Water Supply (Water Fittings) Regulations 1999, Paragraph 18


Appropriate vent pipes, temperature control devices and combined temperature pressure and relief valves shall be provided to prevent the temperature of the water within a secondary hot water system from exceeding 100°C.

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Source: https://www.legislation.gov.uk/uksi/1999/1148/schedule/2/paragraph/18 (the official version)
Page: https://openlegislation.uk/water-supply-water-fittings-regulations-1999/schedule-2/paragraph-18
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.