FLUE SYSTEMS
To evacuate the products of combustion safely and
thoroughly, the boiler must have an efficient flue
system.
DO NOT
fit a new boiler to an older flue
system.
Conventional chimneys
The Contractor boilers operate at high efficiencies, with
low flue gas temperatures. All components used in the
flue system must be suitable for wet flues, and
approved for use with condensing oil boilers.
The flue should rise as vertically as possible, and
terminate at a point not subject to downdraughts and
adverse wind effects. The condensation produced in
the flue should be allowed to run back into the boiler; no
separate drain in the base of the flue is required.
Where a chimney is used, it must be lined with a
stainless steel liner suitable for use with oil-fired
condensing boilers. Before the liner is installed, the
chimney must be thoroughly cleaned of all traces of
soot and scale.
If a rigid flue is to be fitted externally, a twin-walled flue
must be used. The flue must be constructed of a
stainless steel inner skin (suitable for use with oil-fired
condensing boilers). It must also be insulated,
incorporate seals and be weather-protected.
The internal flue diameter must be 100mm (4").
Aluminium or plastic must not be used on any part of
the flue system.
The boiler will operate reliably over a wide range of
chimney
draughts;
as
such,
under
normal
circumstances the flue should terminate with a standard
cowl.
Ensure that all joints on the flue system are adequately
sealed, and that no gases or condensation can escape.
Balanced flues
The Trianco balanced flue system offers greater
flexibility for siting than a conventional flue. In addition
to the siting benefit, the performance of balanced flue
boilers is virtually unaffected by high wind conditions,
as the wind pressures are applied equally to both the
air intake and flue gas discharge sections, creating the
balanced condition. Balanced flue condensing boilers
are also designed to operate at low noise levels.
Some boilers rely on case sealing; Trianco boilers do
not require case sealing as they have a sealed air duct
system that maintains the room sealed performance
even when the front casing is removed for burner
commissioning or adjustment.
The use of the balanced flue principle also enhances
the overall thermal efficiency of the boiler, as the
incoming air extracts waste heat from the flue and
returns it as pre-heated air to the burner, aiding
combustion.
Three types of balanced flue can be fitted to the boiler:
horizontal
(
pages
18
–
19
),
high-level
horizontal
(
pages 20
–
22
), or vertical (
pages 23
–
25
). Bends can
be fitted to the vertical or high-level kits for further siting
flexibility (
page 26
).
During operation, a plume of condensation will
frequently discharge from the flue terminal. As such,
care should be taken when siting the flue to avoid a
nuisance to neighbouring properties. Keep the terminal
clear of infrared sensing devices, such as those used to
control security lighting or alarms. Positioning of flues
under balconies and within carports should also be
avoided.
The flue terminal should not be positioned where the
products of combustion could enter the building (see
fig
14
). Additional clearances may be allowed to prevent
plume nuisance (
fig 15
). If the terminal is less than 2
metres above ground level or any other place to which
a person has access, the terminal must be protected by
an appropriate guard. As the system operates under
positive pressure, it is essential that all flue joints are
sealed.
Trianco balanced flue kits have been designed for
exclusive
use
with
Trianco
boilers;
as
such,
compatibility with other manufacturers' boilers cannot
be guaranteed.
FIG. 13