3
18
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 or, if
appropriate, using a Side Return Air Kit SR50, 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. For heaters on
maximum output the return air duct size should not be less than the equivalent of 300mm x 250mm (12" x 10"). If flexible
duct is used the duct diameter should not be less than 350mm (14") dia. The return air grille should have a free area of
not less than 1266cm
2
(196in
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 minimise airflow resistance. The base duct,
which equalises 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.
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 accept internally the spigot end of a non-asbestos flueto 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
Ventilated from inside
building.
Low level grille
448cm
2
(69in
2
)
High level grille
224cm
2
(34in
2
)
Ventilated from
outside building.
Low level grille
224cm
2
(34in
2
)
High level grille
112cm
2
(14
2
)
Table 1
Minimum Effective Areas
WARM AIR UNIT
HOT WATER GENERATOR
CONTROLS
to comply with the Building Regulations, each section must have a tick on one or other of the boxes
FOR WARM AIR HEATERS ONLY
Has the system been balanced in accordance with the heater manufacturer’s instructions?
YES
NO
Was an anemometer used?
YES
NO
Have balancing dampers been fitted?
YES
NO
FOR WARM AIR HEATING: MEASURE AND RECORD
Burner operating pressure
Mbar
Heat input
KW
Temperature differential between return air inlet and nearest outlet
o
C
FOR HOT WATER GENERATORS: MEASURE AND RECORD
Burner operating pressure
Mbar
Heat input
KW
Water flow temperature
o
C
FOR ALL PRODUCTS
Does the heating & hot water system comply with the appropriate building regulations?
YES
NO
Has the appliance and associated controls been installed & commissioned in accordance with manufacturer’s instructions?
YES
NO
Have you demonstrated the operation of the appliance & system controls to the customer?
YES
NO
Have you left all the manufacturer’s literature with the customer
YES
NO
Competent person’s signature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Customer’s Signature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
(To confirm demonstration of equipment & receipt of appliance instructions)
COMMISSIONING ENGINEER’S DETAILS
Name . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Commissioning Date . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tel No . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CORGI REGISTRATION No . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CORGI ID SERIAL No . . . . . . . . . . . . . . . . . . . . . . . . . . .
BENCHMARK Number
WARM AIR HEATER AND CIRCULATOR
COMMISSIONING CHECKLIST
REQUIREMENT
1. Time & temp control to heating
2. Time & temp control to hot water
3. Heating zone valves
4. Thermostatic Radiator Valves
5. Boiler interlock
MEASURES PROVIDED
Room stat & integral timer
Cylinder stat & Integral timer
Fitted
Not Required
Fitted
Not Required
Provided
Not Required
APPLIANCE SERIAL NUMBER: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . NOTIFICATION No: . . . . . . . . . . . . . . . . . . . . . . . . . . . .
APPLIANCE SERIAL NUMBER: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . NOTIFICATION No: . . . . . . . . . . . . . . . . . . . . . . . . . . . .
169cm
2
(26.2in
2
)
169cm
2
(26.2in
2
)
337cm
2
(52.3in
2
)
85cm
2
(13.1in
2
)
