10
4.
REGULATIONS &
STANDARDS
SOLARcomfort hot water heating systems should be installed in
compliance with the following standards and regulations.
Water Supply (Water Fittings) Regulations 1999 / www.wras.co.uk
These regulations (bye-laws in Scotland) ensure a good supply of
wholesome water and that only approved materials, pipes and fittings are
used to convey water.
These are statutory documents and take priority over all other regulations
and recommendations. The installation of an unvented hot water storage
cylinder is classified as a “Controlled Service” and Regulation G3 applies.
To meet the requirements of the Regulations, installation of an unvented
system should be undertaken by a “competent installer”.
All installations of unvented hot water storage systems having a capacity
of more than 15 litres should be notified to the relevant Local Authority by
means of a building notice or by the submission of full plans. It is important
to note that it is a criminal offence to install an unvented hot water storage
system without notifying the Local Authority. The installation of the unvented
cylinder and hot water system must comply with BS 6700 and the HSE
Legionella Code of Practice.
Current guidance notes do not cover the connection of a solar thermal
circuit to an unvented storage vessel (cylinder). However, if guidance is
sought for compliance with current regulations the fundamental principle
is to provide a fail-safe means of shutting off the solar input to the heat
exchanger if the cylinder temperature should rise above the set temperature
of the cylinder’s energy cut out. (See Note 1).
As with all unvented hot water systems, notification of intention to install
should be given to your local building control.
Option A.
A non self-resetting mechanical shut-off should be installed on
the solar primary flow to the cylinder. The mechanical shut-off should be
suitable for use with a solar primary circuit (i.e. high temperature and glycol
resistant). The mechanical shut-off should be integrated electrically with
the cylinder energy cut out/s and if necessary the solar circuit temperature
control, please refer to the solar controller manufacturer for further
information.
Option B.
Where the solar controller and hydraulic system demonstrate
that by no lesser means the requirement in Option A is satisfied by other
means; certification by an approvals body is required to demonstrate that
in the event of the stored water going over temperature, the heat input to
the cylinder is isolated by physical means and is non self-resetting.
These systems should be clearly identified with reference to the approvals
body. (See Note 2).
Note 1 : Whilst most solar cylinders use a coil type heat exchanger other
options such as external plate to plate devices, external annulars or ‘tank
in tank’ systems may be used but the same control options always apply.
Note 2 : Current approved bodies include the British Board of Agrèment
(BBA), WRc-NSF Limited, or KIWA.
4.1 W
ATER
R
EGULATIONS
4.2 B
UILDING
R
EGULATIONS
4.3 G
ENERAL
G
UIDANCE
