Air Supply And Ventilation - andrews CSC 39 Installation Manual, Operation And Service Manual

SECTION 3
AIR SUPPLY
AND
VENTILATION
18
INSTALLATION
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:
Position of Air Vents
High Level
Low Level
In a Room or
Internal Space
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 (1ft) 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
• High Level (outlet)
270cm 2 plus 2.5cm
Air Vents Areas
Air from Room or Internal Space
10cm 2 per kW
10cm per kW
2
No Requirement for Ventilation
2 per kilowatt in excess of 60kW total rated input.
2 per kilowatt in excess of 60kW total rated output.
Air Direct from Outside
5cm 2 per kW
5cm per kW
2