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27-01-04
VENTILATION REQUIREMENTS
The heater must have both ventilation and
combustion air. Safe and efficient operation of the
heater is vitally dependant upon a good supply of
fresh air to the room in which the appliance is in-
stalled. Minimum requirements for net free air supply
openings direct to outside air at both high and low
level are detailed in the table at the bottom of this
page.
Position grilles to avoid the risk of accidental
blockage or flooding. Further guidance is given in
BS6644.
CAUTION:
Combustion air must not be
contaminated by corrosive chemical fumes which
can damage the heater and void the warranty.
NOTE:
The design is also certified by Advatica for
indoor installation when fitted with appropriate
manufacturer's draught diverter and a suitable flue
system to outside. The heater must be in a room
separated from living rooms and provided with
appropriate ventilation direct to outside. It must not
be installed in a cupboard or compartment which is
directly connected to a living space.
FLUE SYSTEM
WARNING:
Indoor boilers require a draught diverter that must be
connected to a flue pipe and properly flued to the
outside. Failure to follow this procedure can cause
fire or fatal carbon monoxide poisoning.
To ensure safe and satisfactory operation of the
heater, the flue system must be capable of the com-
plete evacuation of flue products at all times. The
effective height of the flue terminal above the draught
diverter must ensure sufficient buoyancy to
overcome the resistance of the bends and horizontal
runs of the flue pipe. The number of bends and length
of horizontal run must be kept to a minimum to reduce
resistance.
The chimney must terminate in a downdraught free
zone.
The flue/chimney design should avoid the formation
of excessive quantities of condensate and for this
reason it is recommended that all chimneys are
suitably insulated and lined.
The draught diverter supplied with the heater must be
used.
Drain points should be fitted at the bottom of all
vertical flue sections. Drain pipes must be a minimum
of 25mm (1 in) internal diameter and manufactured
from acid condensate resistant material (eg stainless
steel) and positioned so that pipe runs and discharge
points are not subject to the effects of frost and that
flue gases cannot leak into the room.
Any terminal fitted must be of a type acceptable to
British Gas plc.
As part of commissioning, the flue must be satisfac-
tory when tested for flue flow and spillage as detailed
in BS5440 Part 1.
Flue.pcx
Model
Input
Plant Room (cm
²
)
ref. BS5440 for models under 60kW
(kW)
Inside
Outside
High
Low
High
Low
055
13
117
234
59
117
105
27
243
486
122
243
155
39
351
702
176
351
185
50
450
900
225
450
265
72
-
-
297
600
405
108
-
-
378
756
ref. BS6644 for models over 60kW
Compliance with the recom-
mendations made in BS 6644;
British Gas publication IM11
"Flues for Commercial and
Industrial Gas fired boilers and
air heaters" and the "Third
Edition of the 1956 Clean Air Act
memorandum" should be strictly
observed where applicable.
