5
or internal space containing a bath or shower.
When an appliance is installed in a room or internal
space containing a bath or shower, the appliance
or any control pertaining to it must not be within
reach of a person using the bath or shower.
The location chosen for the appliance must permit
the provision of a safe and satisfactory flue and
termination. The location must also permit an
adequate air supply for combustion purposes and
an adequate space for servicing and air circulation
around the appliance.
Where the installation of the appliance will be in an
unusual location special procedures may be nec-
essary, BS 6798 gives detailed guidance on this
aspect.
A compartment used to enclose the appliance
must be designed and constructed specifically for
this purpose. An existing compartment/cupboard
may be utilised provided that it is modified to suit.
Details of essential features of compartment/
cupboard design including airing cupboard instal-
lations are given in BS 6798. This appliance is not
suitable for external installation.
3.3
GAS SUPPLY
The gas meter - as supplied by the gas supplier -
must be checked to ensure that it is of adequate
size to deal with the maximum rated input of all the
appliances that it serves. Installation pipes must
be fitted in accordance with BS 6891.
Pipe work from the meter to the appliance must be
of adequate size. Pipes of a smaller size than the
appliance gas inlet connection must not be used.
The installation must be tested for soundness in
accordance with BS6891.
If the gas supply serves more than one appliance,
it must be ensured that an adequate supply is
maintained to each appliance when they are in use
at the same time.
3.4
FLUE SYSTEM
The terminal should be located where the disper-
sal of combustion products is not impeded and
with due regard for the damage and discoloration
that may occur to building products located nearby.
The terminal must not be located in a place where
it is likely to cause a nuisance (see fig. 4).
In cold and/or humid weather, water vapour will
condense on leaving the terminal; the effect of
such pluming must be considered.
If installed less than 2m above a pavement or
platform to which people have access (including
balconies or flat roofs) the terminal must be
protected by a guard of durable material. The
guard must be fitted centrally over the terminal.
Refer to BS 5440 Part 1, when the terminal is 0.5
metres (or less) below plastic guttering or 1 metre
(or less) below painted eaves.
BS 5440
PART 1
FLUES
BS 5440
PART 2
FLUES & VENTILATION
BS 5449
PART 1
FORCED CIRCULATION HOT WATER SYSTEMS
BS 6798
INSTALLATION OF BOILERS OF RATED INPUT NOT EXCEEDING 60kW
BS 6891
LOW PRESSURE INSTALLATION PIPES
BS 7074
PART 1
APPLICATION, SELECTION AND INSTALLATION OF EXPANSION VESSELS AND
ANCILLARY EQUIPMENT FOR SEALED WATER SYSTEMS
3.5
AIR SUPPLY
The following notes are intended for general guid-
ance only. This appliance is a room-sealed, fan-
flued boiler, consequently it does not require a
permanent air vent for combustion air supply.
When installed in a cupboard or compartment,
ventilation for cooling purposes is also not re-
quired.
3.6
WATER CIRCULATION
Detailed recommendations are given in BS 5449
Part 1 and BS 6798. The following notes are for
general guidance only.
3.6.1
PIPEWORK
It is recommended that copper tubing to BS 2871
Part 1 is used in conjunction with soldered capil-
lary joints.
Where possible pipes should have a gradient to
ensure air is carried naturally to air release points
and that water flows naturally to drain cocks.
Except where providing useful heat, pipes should
be insulated to avoid heat loss and in particular to
avoid the possibility of freezing. Particular atten-
tion should be paid to pipes passing through
ventilated areas such as under floors, loft space
and void areas.
3.6.2
AUTOMATIC BY-PASS
The appliance has a built-in automatic by-pass,
consequently there is no requirement for an exter-
nal by-pass, however the design of the system
should be such that it prevents boiler ‘cycling’.
3.6.3
DRAIN COCKS
These must be located in accessible positions to
facilitate draining of the appliance and all water
pipes connected to the appliance. The drain cocks
must be manufactured in accordance with BS
2879.
3.6.4
AIR RELEASE POINTS
These must be positioned at the highest points in
the system where air is likely to be trapped. They
should be used to expel trapped air and allow
complete filling of the system.
3.6.5
EXPANSION VESSEL
The appliance has an integral expansion vessel to
accommodate the increased volume of water
when the system is heated. It can accept up to 10
litres of expansion from within the system, gener-
ally this is sufficient, however if the system has an
unusually high water content, it may be necessary
to provide additional expansion capacity (see
6.19).