Diagram 5.5
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5.9 Unvented DHW System
General - All domestic hot water circuits, connections, ttings
must be in accordance with the relevant standards and water
supply regulations.
For GB: Guidance G17 to G24 and recommendation R17 to
R24 of the Water Regulations Guide.
For IE: The current edition of I.S.813 “Domestic Gas
Installations”.
Where a storage system will not have a vent to atmosphere
the installation must comply with the building regulations and
the Water Supply (water ttings) Regulations 1999 and water
byelaws 2000, Scotland, see also the current issue of BS5546
and BS6700.
If tting to an existing system the local authority should be
informed.
5.10 Domestic Water Cylinder
SINGLE FEED INDIRECT CYLINDERS ARE NOT SUITABLE
AND SHOULD NOT BE USED.
The domestic hot water cylinder must be of the double feed
indirect coil type. It must be suitable for working at a gauge
pressure of 0.35bar above the safety valve setting.