Brivis 18
Ducted Gas Heater IM
4. DUCTING INFORMATION
Good duct design and sizing are essential to every Central Heating system. Use the Product Sizing Guide and
technical data within this manual for the best results and follow these guidelines:
• Ductwork should be well insulated and airtight and have a minimum insulation rating of R1.0 (R1.5 in some
areas). Ensure that ducting complies with the Building Code of Australia.
• The ducting shall be well fastened to pops, BTOs, outlet boots and neck adapters adequately with duct tape, in
accordance with AS 4254.
• It shall also be properly sized, and curves and bends shall be smooth enough to ensure that the air flows
through efficiently, quietly and with minimal resistance.
• The registers and diffusers shall be large enough and of good design. They should minimise noise, while
providing the correct distribution pattern.
• The positive return air system shall be fitted with a grille large enough to accept the full air capacity of the
system at low noise levels and minimum resistance.
• If the system uses high level outlets (e.g. ceiling diffusers), then the return air inlet should be at a low level.
Ceiling systems with a high level return air may result in reduced performance.
Note:
It is important that the ducting should be well insulated. It is mandatory under building codes to install insulated, fire rated duct.
4.1 RETURN AIR GRILLE
If a filter is fitted to the return air grille, make sure it is easily accessible for regular cleaning.
Table 3 below gives the minimum recommended return air grille sizes for each model heater.
Table 3. Minimum Recommended Return Air Grille Selection
Without Filter
With Filter
Model
Grille Size (m²)
Example Size (mm)
Grille Size (m²)
Example Size(mm)
CC315I V2
0.21
(370x560)
0.30
(400x750)
CC320I V2
0.21
(370x560)
0.30
(400x750)
CC320IXA V2
0.24
(530x530)
0.35
(400x1000)
CC325I V2
0.23
(530x530)
0.33
(350x900)
CC325IXA V2
0.26
(530x530)
0.38
(400x1000)
CC330I V2
0.35
(400x1000)
0.51
(400x1350)
CC330IXA V2
0.38
(400x1000)
0.54
(400x1350)
Note:
Sizes are based on maximum airflow for typical 'egg-crate' grilles. For all other types, refer to the manufacturer’s specifications.
Example: If a grille has a free ventilation opening of 370mm x 560mm, the grille size is 0.37m x 0.56m = 0.21m².
This grille would be suitable for a CC315 & CC320 heater provided the grille does not have a filter fitted.
