andrews CWH120/200, Installation, Operation And Maintenance Manual

Page: 29 / 44

MAXXflo Water Heater
29 29 INSTALLATION • SECTION 3
AIR SUPPLY AND VENTILATION 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 apposition 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).
Air Vents Areas
Position of Air Vents Air from Room or Internal Space Air Direct from Outside
High Level 10cm
2
per kW Net input 5cm2 per kW Net input
Low Level 10cm
2
per kW Net input 5cm2 per kW Net input
In a Room or Internal Space No Requirement for Ventilation
Note: Both air vents must communicate with the same room or internal space or both must be on the same
wall to outside air.