Page 359 - The City and Guilds Textbook: Plumbing Book 1 for the Level 3 Apprenticeship (9189), Level 2 Technical Certificate (8202) and Level 2 Diploma (6035)

Chapter 6 Hot water systems

It is interesting to note that Regulation G3 applies to all domestic dwellings,
including greenhouses, small detached buildings, extensions and conservatories,
but only if they are served with hot water supplied from a dwelling.

It should be noted that the local building control officer should be informed
before commencing any installation of a hot water system.

The Building Regulations Approved Document
L1A/B 2013

This document promotes the conservation of fuel and power. The basic outline
to this document is that the building and services contained within a dwelling
must be designed and installed to actively reduce the amount of CO produced.
2
The building fabric must contain insulation to limit heat loss and heating
appliances, associated controls and equipment and lighting systems must all
reduce the energy wasted. Pipes and storage vessels must also be insulated to
reduce the waste of energy.

This document should be read in conjunction with the Domestic Building
Compliance Guide.
INDUSTRY TIP
The Water Supply (Water Fittings) Regulations 1999 A copy of the Water Supply

In many respects, the Water Regulations mirror the Building Regulations, and (Water Fittings) Regulations
these two documents should be consulted before undertaking any design or can be downloaded free
installation of hot water systems. from: www.legislation.gov.
uk/uksi/1999/1148/contents/
Hot water supply is covered in Section 8 of Schedule 2 of the Water Supply made
(Water Fittings) Regulations. The Document G Guidance for Hot Water Supply
is reproduced in Table 6.1, complete with the guidance notes attached to the
Regulations.
 Table 6.1 Document G Guidance for Hot Water Supply
SECTION 8
Schedule 2: Paragraphs 17, 18, 19,
20, 21, 22, 23 and 24: Hot water
services Guidance
17 (1) Every unvented water heater, Unvented hot water systems
not being an instantaneous water G17.1
heater with a capacity not greater than a A temperature control device; and either a temperature relief valve or combined
15 litres, and every secondary coil temperature and pressure relief valve; and
contained in a primary system shall: b An expansion valve; and
a) Be fitted with a temperature control c Unless the expanded water is returned to the supply pipe in accordance with
device and either a temperature Regulation 15(2)(a), either;
relief valve or a combined pressure i An expansion vessel; or
and temperature relief valve; or ii Contain an integral expansion system, such that the expansion water is contained
b) Be capable of accommodating within the secondary system to prevent waste of water.
expansion within the secondary hot
water system. G17.2 An expansion valve should be fitted to all unvented hot water storage systems,
(2) An expansion valve shall be fitted with a capacity in excess of 15 litres, to ensure that expansion water is discharged in a
with provision to ensure that water is correct manner in the event of a malfunction of the expansion vessel or system.
discharged in a correct manner in the G17.3 Where expansion water is accommodated separately the expansion vessel
event of a malfunction of the expansion should preferably be of an approved ‘flow through type’ and should comply with the
vessel or system. requirements of BS 6144 and BS 6920.
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