How Chimneys Work - hergom C-11 Instructions D'installation, De Service Et D'entretien

The installation of the Compact C-11 will have an important
influence on its safety and correct operation.
It is extremely important to be installed properly.
For the correct installation of the Compact C-11 and the
chimney, it is advisable to be performed by a professional.
The Compact C-11 emits heat by radiation, directly heating
the walls, roof, etc., and by forced convection, of the air, to
the ventilator which is installed internally.
2.1 POSSIBILITY OF HOT AIR OUTFLOW.
OUTFLOW VIA THE UPPER GRILLE
This is the STANDARD air outflow for the appliance.
The air enters via the lower section "A" and the
ventilator inside the appliance expels the hot air
through the upper section "B".
OUTFLOW VIA THE HOOD
This option is compatible with the previous one.
It is compulsory for masonry hoods to have some gaps
in the lower and upper sections. These gaps may be
covered with decorative grilles. This facilitates an
ascending air flow, with cold air entering from the lower
section "C" and hot air is expelled from the upper
section "D" ( remember that the compact C-11 emits
most of its heat by convection ). If the masonry hood
does not have sufficiently large ventilation grilles,
breakages to the appliance may occur, as the heat is
not dissipated.
IMPORTANT ! The minimum recommended section for
air intake of the grilles is 200 cm ² of air clearance per
grille. (The hood's air intake grilles must be
positioned in such a way that they cannot be
blocked).
2.2
CHIMNEYS.
The operation of the Compact C-11 depends on:
a) The chimney.
b) The chimney operating method.
c) The quality of the fuel used.
Following years of use, you may change the type of fuel
but the chimney is not easily modified or moved once it has
been installed in a specific position. The following information
will help you decide whether the existing chimney may be
used or whether a new chimney should be built.

2.2.1. How Chimneys Work

A basic understanding of how chimneys work will enable you
to obtain improved performance of your Compact C-11,
whereby their main functions are.
c) Evacuate smoke and gases from the hearth in a safe
way.
d) Provide sufficient flue in the hearth so that the fire
stays lit.
What is the flue?
The tendency of hot air to rise creates a flue.
When the compact C-11 is lit, the hot air rises up the
chimney and goes outside. The chimney pipe gets hot
and maintains the flue. The flue does not work properly
until the stove and the chimney are hot.
The location, size and height of the chimney affect the
flue.
The following must be considered:
- Chimneys located within the house remain hot;
therefore the flue is greater.
- The manufacturer's recommended size of the
chimney maintains a good flue.
- The height of the chimney affects the flue: More
height, Better flue.
The chimney should stick out at least one metre from the
highest part of the roof.
There are other factors which affect the flue:
- Trees and/or tall buildings close to the dwelling.
- The speed of the wind. In general, strong, continuous
winds increase the flue; but gusty winds reduce the flue.
- External temperature. The colder it is outside, the better
the flue.
- Barometric Pressure. On rainy, wet or stormy days, the
flue is generally weak.
- Briskness of the fire. The hotter the fire is, the stronger
the flue.
Cracks in the chimney, poorly sealed or dirty doors, air
intakes due to the joining of pipes, other appliances
connected to the
inappropriate flues.
2.2.2. Build-up of Creosote and its Cleaning
Slow burning wood produces tar and other organic
vapours, which combine with atmosphere moisture to form
creosote. These creosote vapours may condense if the chimney
walls are cold. Extremely hot fires may occur if the creosote
ignites. Any build-up of creosote must be eliminated. It is
extremely difficult to predict exactly when the chimney should
be cleaned. Visual inspection is the safest way of checking
whether your stove is creosote free. For this reason, we
recommend that the installations are easily accessible for
inspection.
2.2.3. Options.
If you are going to build a chimney for the Compact
C-11, there are two alternatives:
e) Masonry Chimney.
f) Metal Chimney
Studies show that there is not much difference in terms of
flue performance between metal and masonry chimneys. It is up
to you to choose one or the other, depending on your criteria.
Whenever possible, locate your chimney inside the house,
hence obtaining a better flue, less creosote build-up and a
longer duration.
THE ADVANTAGES OF MASONRY CHIMNEYS ARE:
e) The mass of bricks and floor tiles reduce the cooling of
the vapours in the chimney.
f) The heat accumulating characteristic of bricks allows
the house to be kept warm for a longer period once the fire has
gone out.
g) It can be built to suit individual taste.
h) If it is well built, it may be more resistant to fire than
metal chimneys.
Masonry chimneys should be well lined to avoid the
cooling of vapours. They should be built with materials that
withstand high temperatures and corrosion. They may be round,
square, etc.; what is important is their internal section.
The measurements indicated in section 9 TECHNICAL
INFORMATION should be respected for Compact
C-11 masonry chimneys.
THE ADVANTAGES OF METAL CHIMNEYS ARE:
f) Easy installation.
chimney, etc. may produce