Johnson & Starley WARMCAIR C16D, Руководство пользователя

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8. DUCT SYSTEM
(See British Design Manual - Gas fired Warm Air Heating)
8.1 RETURN AIR
8.1.1 A room-sealed heater can be installed without positive return air ducting, provided that the path
between the return air grille and the heater return air inlet is protected in such a manner that the
required airflow is maintained at all times (BS5864).
8.1.2 The return air grille MUST have a free area of not less than 900 cm² (140 in²). It is recommended that
the return air duct not be routed directly from the main living area, but from a convenient central area
serving the remainder of the dwelling.
8.1.3 The return air system should be constructed of fire-resistant material where used. It is extremely
important that the correct size of return air grilles and ducting is used. The return air duct area should
not be less than 450 cm² (70 in²). If flexible duct is used the duct diameter should not be less than 300
mm (12”) diameter.
8.1.4 An adequate and unobstructed return air path is essential from areas not served by a directly ducted
return and to which warm air is delivered. All such rooms should be fitted with relief grilles which have
a free area of 0.0088 m2/kW (1 in²/250 Btu/h) of heat supplied to the room. The only exceptions are
kitchens, bathrooms and WCs.
8.1.5 The return air duct should allow for ease of removal for access to the flue.
8.1.6 All duct work in the room or internal space in which the heater is installed shall be mechanically secured
and sealed with ducting tape.
8.1.7 If a return air duct is not to be fitted, the top of the unit must be suitably guarded to prevent blockage
8.2 WARM DELIVERED AIR
8.2.1 All duct work, including riser ducts, should be fully insulated with 50mm (2”) fibre-glass or similar. If
short extended duct runs are taken below floor level these should be similarly insulated and in addition
wrapped with a sound vapour proof barrier. They must also be protected from crushing.
8.2.2 The duct system should be carefully designed (as given in the guidelines in the British System Design
Manual) to suit the needs of specific heating requirements and building layout. The type of duct
system (e.g. radial/extended plenum/ stepped) should be installed using the least number of fittings to
minimise airflow resistance. The base duct, which equalises the air pressure to supply ducts, must be
constructed to support the weight of the heater, which must be sealed using self-adhesive foam strip,
ducting tape or sealing compound. All ducting and blanking plates must be mechanically secured and
sealed.