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Where the boiler is to be installed in a cupboard or
compartment, permanent high and low level air
vents are required for cooling purposes in the cup-
board or compartment. Both vents must communi-
cate with the same wall to outside air.
The minimum effective area of the permanent air
vents required in the cupboard or compartment are
given in Table 3.
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Detailed requirements are given in BS 5440.2
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The expansion vessel is suitable for systems up to
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water content. For systems in excess of
this capacity an additional pressurised expansion
vessel will be required. BS7074 and "British Gas
Specifications for Domestic Wet Central Heating
Systems’ Part 3 gives guidance in this subject.
The central heating system should be in accordance
with the relevant recommendations given in
BS.6798 and, in addition, for small bore and micro-
bore systems - BS.5449.1. The domestic hot water
system, if applicable, should be in accordance with
the relevant recommendations of BS.5546.
Copper tubing, to BS. 287 1. 1, is recommended for
water carrying pipework.
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Wiring extemal to the boiler must be in accordance
with the I.E.E. Wiring Regulations and any local re-
gulations.
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High level
186 cm²
93 cm²
29 in²
15 in²
Low level
186 cm²
93 cm²
29 in²
15 in²
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