VENTILATED
Low level grille
184cm
2
(28in
2
)
FROM INSIDE
BUILDING
High level grille
92cm
2
(14in
2
)
VENTILATED
Low level grille
92cm
2
(14in
2
)
FROM OUTSIDE
BUILDING
High level grille
46cm
2
(7in
2
)
Table 1: Minimum Effective Areas
4.
DUCT SYSTEM
(See British Design Manual - Gas fired Warm Air Heating)
4.1
RETURN AIR
4.1.1 All return air shall be POSITIVELY ducted from outside the compartment to the top of the unit via a return air duct,
and mechanically secured. It is recommended that the return air duct be not routed directly from the main living
area, but from a convenient central area serving the remainder of the dwelling.
4.1.2 The return air system should be constructed of fire-resistant material. The flue shall not be run through an area
serving as a return air path. It is extremely important that the correct size of return air grilles and ducting is used.
The return air duct size should not be less than the equivalent of 200mm x 200mm (8" x 8"). If flexible duct is used
the duct diameter should not be less than 254mm (10") dia. The return air grille should have a free area of not less
than 650cm
2
(100in
2
).
4.1.3 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 0.0088m
2
/
kW (1in
2
/250Btu/h) of heat supplied to the room. The only exceptions are kitchens, bathrooms and WC.’s.
4.1.4
The return air duct should allow for ease of removal for access to the flue.
4.1.5
All duct work in the room or internal space in which the heater is installed shall be mechanically secured, and
sealed with ducting tape.
4.2
WARM DELIVERED AIR
4.2.1
All duct work, including riser ducts, should be fully insulated with 50mm (2in) fibreglass 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, and protected from crushing.
4.2.2
The duct system should be carefully designed (as given in the guidelines in the British System Design Manual) to
suit the needs of its specific heating requirements and building layout. The type of duct system, (i.e. radial/
extended plenum/stepped) should be installed using the least number of fittings to minimize airflow resistance.
The base duct, which equalizes the air pressure to supply ducts, shall be constructed to support the weight of the
heater, which shall be secured to the plenum with screws on at least two sides, and sealed using self-adhesive
foam strip, ducting tape or sealing compound. All ducting and blanking plates shall be mechanically secured and
sealed.
5.
INSTALLATION REQUIREMENTS
5.1
FLUES
(see British Standards BS 5440 Pt.1 Flues)
5.1.1
All joints shall be soundly sealed.
5.1.2
The flue should be kept as short and warm as possible, but must have a minimum equivalent height of 1m..
5.1.3
Sufficient support brackets shall be installed to bear the weight of the total flue system.
5.1.4
The spigot connection of the heater draught diverter will internally accept the spigot end of a non-asbestos flue
to BS 567 or twin wall metal flue to BS 715 of nominal 100mm (4in) diameter.
5.1.5
A split collar should be fitted to provide for flue maintenance or inspection.
5.1.6
The flue shall be in accordance with the Building Regulations and British Gas Materials and Installations
specification (3rd edition) with regard to clearance and shielding from combustible materials.
5.1.7
All materials shall be in accordance with Building Regulations requirements.
5.1.8
The flue should run as vertically as possible. Horizontal runs should be avoided if at all possible and any
directional change should be as gentle as possible. If there is any doubt about the flue configuration, the
equivalent flue height should be determined (see 5.1.10).
5.1.9
If the appliance to be fitted is a replacement, the old appliance should be checked for signs of spillage prior to
commencement of the installation and appropriate action taken, (i.e. check flue system and renew as necessary).
3
ZZ1031/4
ZZ1031/4
16
Fig. 5, JB25P Mk 5 CIRCUIT DIAGRAM
Содержание JB25P MK 5
Страница 18: ...18 ZZ1031 4 Fig 7 PRINCIPAL DIMENSIONS mm ...
