8
If there is an extraction fan fitted in adjacent rooms
where this appliance is fitted, additional air vents
may be required to alleviate the possibility of
spillage of products of combustion from the appli-
ance/flue while the fan is in operation. Refer to B.S.
8303 Part 1.
Where such an installation exists, a test for spillage
should be made with the fan or fans and other appli-
ances using air in operation at full rate, (i.e. extrac-
tion fans, tumble dryers) with all external doors and
windows closed.
If spillage occurs following the above operation, an
additional air vent of sufficient size to prevent this
occurrence should be installed.
Especially Airtight Properties:-
If the stove is being fitted in a property where the
design air permeability is less than 5m
3
/ (h.m
2
) (nor-
mally newer properties built from 2006), then a per-
manent ventilation must be fitted to provide 550mm
2
of ventilation for each kW of rated output. If a draught
stabiliser is also fitted then the requirement is
850mm
2
per kW of rated output.
EXTERNAL DUCTED AIR
An outside air kit which will allow for the air supply
for the stove to be ducted from outside and is avail-
able to order for connection to the stove.
It is recommended to bring the air supply for the
stove into the house using a 4” plastic pipe. Where
the pipe meets the outside wall make sure a vent
cover is fitted properly to ensure no rodents can
enter via the vent pipe.
The vent pipe should be located to prevent the
ingress of moisture and in a location where it will not
get blocked with leaves or any other debris. As wind
effects can create suction and pressure zones of
opposite sides of the dwelling it is recommended to
run the air vent from opposite poles (North, South,
East & West) of the dwelling and tee off for the air
supply to the stove. This should negate the effect
of suction and pressure zones. See Fig.6
‘HETAS product approval covers this appliance
when installed in accordance with the manufactur-
er’s instructions and relevant standards. As there is
currently no standard for Ducted Combustion Air
Supply this does not fall within the remit for HETAS
product approval. Responsibility for the specification
of this and for appropriate manufacturer’s instruc-
tions is carried by the appliance manufacturer, as
allowed for under the Building Regulations.’
Fig.6
Note: When Installing
outside air pipe adhere
to ‘Clearance to
Combustible’ Section.
