14
Horizontal flue installations: Distance
from heater connection to terminal must
not exceed the following length-
LCSBD 95–145
8 Metres
in overall length.
Each 90
°
bend corresponds to 1Mtr of flue
length
Each 45
°
bend corresponds to 0.8 Mtr of flue
length
Flue pipe should be supported at intervals
not exceeding 1.8 M
In order to provide adequate natural
draught, the minimum length of horizontal
flue must not be less than 1M.
For vertical flue installations the flue should
rise vertically where possible bends should
not exceed 45
°
and the number of bends
should be kept to a minimum.
Vertical flue installations: Distance from
heater connection to terminal must not
exceed 10 Metres.
The temperature of the combustion products
can be as high as
170
°
C
and therefore
tend to rise naturally within the flue.
Unnecessary bends and restrictions should
therefore be avoided.
Provision for the disconnection of the flue for
servicing and inspection purposes must also
be made.
The position of the flue and its terminal
should be such that it does not impair the
combustion process. It should terminate in
an exposed position so as to allow the free
escape of flue gases without risk of their
re-entering the building through windows,
ventilation ports etc.
The following distances in mm should be
observed
200
below guttering or eaves.
300
from corners or openings (windows
doors etc) and from other horizontal
terminals on same wall.
1200
from a facing surface.
1500
from another terminal vertically on the
same wall.
2000
from ground level.
The heaters must be connected to the flue
system supplied by Nortek Global HVAC
and be capable of withstanding the stresses
and loadings associated with normal use.
When designing the flue system the
prevention of the formation and entrapment
of condensation must be a key
consideration.
Horizontal flue should be fitted ensuring a
slight gradient approx 2
°
towards the
terminal.
Where condensation is unavoidable traps
should be included to encourage the
condensates to flow freely to a point from
which they may be released, preferably into
a gully.
The condensate pipe from the flue to the
disposal point must be made from corrosion
resistant pipe of not less than 25mm internal
diameter.
If the flue passes through a wall, ceiling, or
roof made from combustible material then it
has to be sleeved so as to provide a
minimum of a 25mm void between the
exterior of the flue and the internal wall of
the sleeve.
Caution
It is imperative that the flue should be
properly sealed where it passes through the
roof, this can best be achieved by using the
approved method of roof flashing plate and
cravat. The flue spigot outlet on all LCSBD
heaters is in horizontal configuration.
Note
It should be noted that claims made under
warranty and attributed to the ingress of
water may not be considered especially if an
approved method of sealing has not been
used, or if the design of the flue has not
made provision for possible condensation
problems.
It is also recommended that BS5854 and
BS5440: parts 1 and 2 are used as a
