Air Supply And Ventilation - Conventional Fl Ue Systems - andrews CWH30/200 Installation, Operation And Maintenance Manual

AIR SUPPLY AND VENTILATION CONVENTIONAL
FLUE SYSTEMS
Th e minimum effective areas of the permanent air
vents require in the compartment are as follows:
Air Vents Areas
Position of Air Vents
High Level
Low Level
Note: Both air vents must communicate with the same room or internal space or must both be on the same wall to
outside air.
IMPORTANT!
1. Th e effective area requirements specifi ed in the
table are related to the maximum heat input of the
heater(s) and are equivalent to those specifi ed in
BS6644 and IGE/UP/10, Pt 1.
2. Th e free area of the grilles should not be less than
the size of the recommended ventilation opening.
3. Th e 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
NOTE! Natural inlet with mechanical extraction
must not be used.
Where a mechanical inlet and mechanical extraction
system is used, the design extraction rate must not
exceed one third of the design inlet rate.
All mechanical ventilation systems must be fi tted
with automatic gas shut off safety systems which cut
off the supply of gas to the heater(s) in the event of
failure of either the inlet or extract fans.
Th e requirements for air supply by mechanical
ventilation are given in BS6644 and IGE/UP/10 Pt 1.
Air from Room or Internal Space
10cm 2 per kW Net input
20cm 2 per kW Net input
Th e permanent air vents shall be sited away from any
extract fans. Where an extract fan is fi tted, check for
spillage at the draught diverter as detailed in BS5440.
It may be necessary to increase the ventilation are to
compensate for the extract fan.
Th e vapours emitted by halogen based compounds
can, if drawn into the combustion air, cause corrosion
of the gas burner, thermocouple and storage vessel.
Th erefore, if heaters are to be installed in locations
where halogens are likely to be present, they should
be isolated from such compounds and ventilated from
and to outside uncontaminated atmosphere.
Some of the vulnerable areas are:
(a)
(b)
(c)
(d)
MAXXfl o Water Heater
INSTALLATION • SECTION 3
Air Direct from Outside
5cm 2 per kW Net input
10cm 2 per kW Net input
Hairdressing salons and adjoining rooms and
basements
Establishments where dry cleaning solutions
are used or stored
Degreasing plants using hydrocarbon
solvents
Premises where refrigerant gases are used or
stored
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