Installation guide

INSTALLATION SECTION 3
AIR SUPPLY
AND
VENTILATION
CONCENTRIC
FLUE SYSTEMS
29
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;
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 vents should have negligible resistance and must not be sited in any position where they
are likely to be easily blocked or 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)
540cm
2
plus 5cm
2
per kilowatt in excess of 54kW total net input.
• High level (outlet)
270cm
2
plus 2.5cm
2
per kilowatt in excess of 54kW total net input.
Position of Air Vents Air from Room or Internal Space Air Direct from Outside
High Level 10cm
2
per kW Net input 5cm
2
per kW Net input
Low Level 10cm
2
per kW Net input 5cm
2
per kW Net input
In a Room or
Internal Space No Requirement for Ventilation
Air Vents Areas