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Iinstallation Requirements
2.4 Gas Supply
2.1 Related Documents
The installation of the heater must be in accordance with the
relevant requirements of the Gas Safety (Installation and Use)
Regulations, Building Regulations and the Byelaws of the
local Water Undertaking. It should be in accordance also with
any relevant requirements of British Gas and local authority,
and the relevant recommendations of the following current
British Standard Codes of Practice :
BS 6891 :
BS 5546 :
BS 5440 :
Specification for installation of low pressure
gas pipework up to 28 mm (RI) in domestic
premises (2nd family gases).
Installation of gas hot water supplies for
domestic purposes (second family gases).
Flues and air supply for gas appliances of
rated input not exceeding 60 kW (lst, 2nd
and 3rd family gases).
Part 1 Flues
Part 2 Air Supply
2.3 Air Supply
IMPORTANT: This heater should be used in a well ventilated
room. An air vent direct to outside is required where the
room volume is less that 20 m3 size in accordance with the
foIlowing table. In addition an openable window is required.
This heater must not be installed in a space less than 5 m3 in
total volume.
Room
Volume Permanent
Air vent Openable
Window I
0-5m3 Installation
not permitted
5m3-10m3 100 cm2 YES
11 m3-20m3
50
cm2 YES
over 20 m3 NIL YES
This water heater is fitted with an atmospheric sensing
device which will turn off the gas supply to the pilot and
burner, when the oxygen in the atmosphere in the locality of
the heater is diminished and will not support safe
combustion. It also protects the user if the heat exchanger
fins become blocked.
It is therefore important that the heater is not located over a
cooker or in a position where the air supply is restricted or
contaminated.
The location must also permit space for servicing and air
circulation around the appliance.
An adequate sized gas meter must be connected to the
service pipe. Where necessary British Gas will arrange for the
existing meter to be checked or for a suitable meter to be
installed. On no account must any work be carried out on
the gas meter other than by British Gas or their specifically
authorised contractor.
Installation pipes should be fitted in accordance with BS
6891: Pipework from the meter must be of adequate size.
Pipes of a smaller size than the gas connection should be
not used,
The complete installation must be tested for gas soundness
and purged in accordance with BS 689 1.
In addition to any other gas appliance installed in the
premises, the meter should be capable of passing : 40 cu,
it/h of natural gas.
2.5
Description of Operation of Special
Components
2.5.1 Atmospherk Sensing Device
The thermoelectric circuit is fitted with a thermal switch
located on the front of the combustion chamber of the
heater. When the oxygen in the atmosphere in the locality of
the heater becomes diminished and is unable to support
safe combustion, the products of combustion pass through
an oriiice in the front panel and the increase in temperature
is detected by the thermal switch. When the switch is
activated it interrupts the thermoelectric circuit and the pilot
and main burner are extinguished.
2.5.2 Scale Reducer
The scale reducer is a diaphragm vessel forming part of the
water section. At the termination of a demand cycle the
contens of the heat exchanger are displaced into the vessel
and replaced with cold water.
2.6 Flue
These appliances are ffueless. Protection is provided in the
form of the atmospheric sensing device (see Section 2.5.1).
They must not be operated continuously for more than fnre
minutes.
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