Air Supply And Ventillation; Concentric Flue Systems; Air Vents Areas - andrews ECOflo Series Installation And Service Manual

3.29 Air supply and ventilation
Position of Air Vents
High Level
Low Level
In a Room or Internal Space
Issue 2 14/07/16
Air from Room for Internal Space
10cm² per kW Net input
10cm² per kW Net input
No requirement for Ventilation

3.29.1 Concentric flue systems

The following notes are intended to give guidance:
Where the heater is to be installed in a room, NO VENTS ARE
REQUIRED.
Where the heater is to be installed in a COMPARTMENT,
permanent air vents are required in the COMPARTMENT at high
and low level. These air vents must either communicate with a
room or internal space or be direct to outside air.
The minimum effective areas of the permanent air vents
required in the compartment are as follows:
Air vents should have negligible resistance and must not be
sited in any position where they are likely to be easily blocked,
flooded or in any position adjacent to an extraction system which
is carrying flammable vapour.
Consideration must be given to the position of the high level
ventilation opening. A high level vent must not be sited within
300mm measured vertically of the flue terminal.
Grilles and louvres should be so designed that high velocity air
streams do not occur within the space housing the heater(s).
The grilles should have a total minimum free area for the water
heater(s) in addition to any other requirements as follows:
• Low level (inlet)
540cm² plus 5cm² per kilowatt in excess of 54kW total net
input.
• High level (outlet)
270cm² plus 2.5cm² per kilowatt in excess of 54kW total net
input.

3.29.2 Air vents areas

Note
Both air vents must communicate with the same room or
internal space or must both be on the same wall to
outside air.
Air Direct from Outside
5cm² per kW Net input
5cm² per kW Net input
No requirement for Ventilation
Note
IMPORTANT:
1. The effective area requirements specified in the table
are related to the maximum heat input of the
heater(s), and are equivalent to those specified in
BS6644.
2. The free area of the grilles should not be less than
the size of the recommended ventilation opening.
3. The supply of air to a space housing the heater(s) by
mechanical means should be;
(a) Mechanical inlet with natural extraction.
(b) Mechanical inlet with mechanical extraction.
Installation 3
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