3. The flue pipe should be of 125mm (5”) diame-
ter rigid insulated stainless steel pipe, that con-
forms to B.S. 4543 and B.S. 5410.
4. The flue pipe should be clamped to the outside
wall at intervals not greater than 1 meter with the
top clamp at the highest possible fixing point
underneath the roof.
5. Two 135
o
bend flue sections must be used to
clear the roof.
6. A suitable flue terminal, such as an OH cowl,
should be fitted to the flue termination point.
FLUE TERMINATION HEIGHT
The flue termination must be high enough (4.6 metres
/ 15 feet minimum height) to allow the flue gases to
vent into clear air, away from turbulence that may be
caused by roof structures, other chimney stacks ,
trees etc.
Fig.13 shows the positions for the flue terminations
for both internal and external flues (as per the Building
Regulations). For an internal flue or chimney, the ter-
mination point should be not less than 600mm higher
than the highest point of the roof or where the termi-
nation point is greater than 600mm from the highest
point of the roof, it must not be less than 1 meter
above the roof.
Fig.13
FLUE STABILISER
The stove is fitted with a flue stabiliser (See Fig.11),
which will help to ensure a stable draught is main-
tained through the stove when the flue is subjected to
a varying flue draught. It works by opening to provide
an additional air supply to the flue whenever the flue’s
negative pressure reaches its upper limit and so pre-
vents the negative pressure in the stove rising above
its optimum level. The flue stabiliser should be ad-
justed to give a maximum draught to 12 pascals.
Fig.14
For external flues, the termination point must be po-
sitioned such that its adjacent point on the roof is not
less than 2300mm from it.
NOTE:
The flue stabiliser must have access to an
adequate air supply at all times.
VENTILATION & COMBUSTION AIR
REQUIREMENTS
It is imperative that there is sufficient air supply to sup-
port proper combustion. The air supply to the stove
must comply with B.S. 5410: Part 1 and the relevant
sections of the OFTEC Technical Book No.3.
If there is an air extraction fan/s, tumble dryer or any
other air using appliance fitted in the room or adjacent
rooms to where this stove is installed, additional air
vents must be provided to prevent the performance
of the stove being affected when the fan/s are running
at their maximum setting with all external doors and
windows closed.
We recommend that air supply to extract fan/s be lo-
cated where it can serve the fan/s, without the air sup-
ply passing through the area where the appliance is
installed.
The room containing the stove should have a perma-
nent ventilation opening of free area at least 550mm
2
for each kW of rated output above 5 kW, but in no
case less than 6,500mm
2
.
All materials used in the manufacture of air vents
should be such that the vent is dimensionally stable
and corrosion resistant.
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