Northline Express EXHAUSTO RS 12, Руководство по применению

Страница: 6 / 35

n
Bad fireplace design
Not only the chimney, but also the fireplace, stove
or other appliances may cause smoke to be omitted
into the room. Here are some typical problems:
The fireplace opening may be oversized for the
chimney. Normally the area of the opening should not
exceed 10-12 times the flue area.
The lintel could be too wide. The width should not be
greater than 4".
The smoke chamber could be too short. It should
not be less than 18" high. Or it could be asymmetrical
with a flue that is not centered.
Excessive projections from the damper, sharp angles
in the masonry or anything else working against an
aerodynamic smoke chamber or throat design.
Among critical fireplaces are the so called “Walk-In”
fireplaces (very big fireplaces), and free-standing fire-
places open on all sides.These fireplaces must capture
the air in the same way as an exhaust hood, which
requires a really good draft in order to maintain a high
velocity over the fireplace opening.
Finally, there is the see-through fireplace, that is
open on two sides. A high percentage of this type of
fireplace have draft problems, and problems with tur-
bulence in the firebox. Very often this is caused by a
flue that is too small, a bad aerodynamic design of the
smoke chamber, the non-existence of same - or, a
combination of all.
Most problems are created when a regular one-
sided fireplace is converted into a see-through fire-
place by knocking the back-wall out and design an
opening.
n
Modern insulation of dwelling
When houses are efficiently insulated there is usu-
ally not sufficient air for combustion. Very often make-
up air vents do not exist resulting in air starvation, and
under these conditions there simply is no draft avail-
able.
Air starvation can only be overcome by induced
draft, but at the same time it should be considered to
install make-up air vents. Other appliances using air for
the combustion, like fireplaces, furnaces, water heat-
ers etc. can also cause smoking fireplaces.
n
Ventilation
Modern buildings have an in-creasing number of
exhaust fans pulling air out of the building. They can be
found in kitchens and bath-rooms, but also central
vacuum-cleaners, dryers and more can pull air out.
The buildings will soon be operating in a depressur-
ized mode - the positive pressure is outside and the
negative inside the building. The result is that outside
air is pulled into the building through openings and
cracks, and the chimney is very often the best vent!
The situation is aggrevated in restaurant kitchens.
Woodfired appliances, like fireplaces, BBQ's and pizza
ovens, can be severely affected by kitchen exhaust
fans, even when these are well balanced.
EXHAUSTO
Fig. 4
Fig. 3
5
NorthlineExpress.com http://www.northlineexpress.com Toll-Free 1-866-667-8454