Potterton SIRIUS FS Installation & Servicing Instructions Manual page 36

5.5.3 B Flue - Ventilation Requirements
23
R
efer to BS 6644 clause 19 and BS 5440 part 2 for detailed recommendations.
The room in which an boiler is installed must have a permanent air vent to outside air
or to a room which itself has direct access to outside air. Installations in boiler rooms
require permanent vents for air supply purposes, one at high level and one at low level,
direct to outside air. The minimum free areas required are as follows:-
Position of air vents
Low Level
High Level
Where the boiler is to installed in a compartment, permanent air vents are required at high
and low level. These air vents must either connected with a room or internal space, or be
direct to outside air. The minimum free air requirements in the compartment are as follows:-
Position of
Air Vents
High Level
Low Level
A compartment containing an open-flued appliance shall be labelled as follows:
IMPORTANT: Do not block the vents. Do not use the compartment for storage.
5.5.4 B Flue - Ventilation Seasonal Adjustments
23
Where a boiler is to operate in summer months, the above allowance should be sufficient,
provided it does not operate for more than 50% of the time. If the boiler is to be operated at
75% then an additional 1cm
be operated 100% of the time during the summer, an additional 2cm
be required at low and high level.
Sirius FS
Area of free air required
400 = 1,800 cm ²
525 = 2,200 cm
400 = 900 cm ²
525 = 1,100cm
Air from room or Internal Space
400 = 4,500 cm ²
525 = 5,500 cm
2
400 = 9,000 cm ²
525 = 11,000cm
2
will be required per kW at low and high level. If the boiler is to
2
34
2
2
Air direct from Outside
400 = 2,250 cm
2
525 = 2,750 cm
2
400 = 4,500 cm
2
525 = 5,500 cm
2
free-area per kW will
2
GB/IE