andrews CWH120/200, Руководство по установке, эксплуатации и обслуживанию

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INSTALLATION SECTION 3
29
AIR SUPPLY
AND
VENTILATION
CONVENTIONAL
FLUE SYSTEMS
IMPORTANT!
1. The effective area requirements specified in the table are related to the maximum
heat input of the heater(s) and are equivalent to those specified in BS 6644 &
IGE/UP/10 Pt1.
2. The free area of the grilles should not be less than the size of the recommended
ventilation opening.
3. The 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 fitted 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.
The requirements for air supply by mechanical ventilation are given in
BS 6644 Clause 19.3 & IGE/UP/10 Pt1.
The permanent air vents shall be sited away from any extract fans. Where an extract
fan is fitted, check for spillage at the draught diverter as detailed in BS 5440 Part 1
Appendix B.
It may be necessary to increase the ventilation area to compensate for the extract fan.
4. The vapours emitted by halogen based compounds can, if drawn into the combustion
air, cause corrosion of the gas burner, thermocouple and storage vessel. Therefore, 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) Hairdressing salons and adjoining rooms and basements
(b) Establishments where dry cleaning solutions are used or stored.
(c) Degreasing plants using hydrocarbon solvents.
(d) Premises where refrigerant gases are used or stored.
The minimum effective areas of the permanent air vents required in the
compartment are as follows;-
Air Vent Areas
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 20cm 2 per kW
Net input
10cm 2 per kW
Net input
Note:- Both air vents must communicate with the same room or internal space or must
both be on the same wall to outside air.
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