Operation Manual

2. FIRING PROCESS
2.1. Fuel quantity and firing process adjustments
Burning wood, wood cakes (or coal cakes – optional) in the fireplace stove is based on
burning through the fuel, which means that such firing takes place throughout the whole go
of the fuel at a time. In order to provide optimal conditions for easy kindling and burning
up, you need enough air being led under the fuel in fire, through the grate: this is the so-
called primary air, and it must be always adjustable. By increasing temperature of the fuel
burning through, certain gaseous components of the fuel evolve that – unless additional air
is supplied – would be of no avail in terms of heat energy: therefore, additional air must be
provided at the flame level where the firing process connected with those gaseous
components may continue. Now, at this stage, the primary air is – in fact – not necessary,
while secondary air supply is required, or tertiary air may be added as well, respectively.
The secondary air supply, usually adjustable, improves the firing process and contributes to
the door glass self- cleaning. The tertiary air supply is designed for general improvement of
the firing process and is usually fixed (one cannot regulate it in any way). If the proportion
of the air volumes led into the particular sections of the firing chamber is correct, the
burning efficiency is increased while emission of pollutants in the environment is reduced.
The layout of the air supply regulative elements is shown in the Technical Cart (a part of
the documentation supplied with the fireplace stove).
Our models of fireplace stove may reach up to 85% efficiency – which means top
performance.
The heating capacity of the heating device depends on the fuel quantity burnt per defined
time, fuel quality and firing process efficiency. Using the Chart 2 (heating values) may
help you to make a picture of attainable capacity: let’s assume that you burn 1 kg of
wood per hour, wood humidity is 20%. Further, with higher wood moisture its heating
capacity goes down.
In the testing room conditions, adjustability of the heating device was tested, within 30 –
100% of nominal performance. For the regulation, the chimney effect and the fuel quantity
were applied. In practice, the heating capacity may be regulated by means of air supply
regulating elements (especially the primary air inlet).
There is no simple and explicit way to
determine the firing process adjustment by means of regulators. There are many aspects to
consider – fuel moisture, type of fuel, chimney effect, exterior pressure conditions, etc.
Therefore, the firing process (the flame intensity and quality) should be re-adjusted for
particular conditions.
You will be able to adjust the firing process to achieve best efficiency after a short time of
operation. A detailed chart showing how to adjust the air supply regulating elements is
included in the technical specifications. The figures in the chart are the testing results
verified by the State Testing Laboratory. The Chart 1 presents just general information for
air supply adjustment.
Primary air Secondary air
Tertiary air
Fuel Fuel quantity
Adjustable Adjustable No adjustment
wooden logs
wood cakes
2 - 3 logs (approx. 2 – 3 kg)
2 - 4 logs (approx. 2 – 3 kg)
Open wide
Fixed adjustment
at installation
coal cakes 2 - 3 logs (approx. 2 – 3 kg)
Closed or open
(depends on local
conditions)
half-open
Fixed adjustment
at installation
Chart 1
Our tips for wood burning
Any time you set the fire, let the primary air regulator open long enough to allow the fuel
burning properly.
Before you re-load, it is recommended to open the primary air regulator wide.
While burning wood, make sure the wood is dry, maximum moisture 20%.
Our tips for coal cake burning (selected models only)
• To achieve optimisation of the firing process, load the cakes directly onto the grate
holes: this way, you support the burning in best possible way.
• Make sure you do not overload: for the heat capacity you may use, i.e. to maintain the
heat, a couple of cakes is enough: otherwise the device would suffer from excessive
heat. Coal cake fuel efficiency may reach 6 kWh/1 kg, i.e. by some 40% more
than wood!
2.2. Fuel
In fireplace stoves, you may burn logs, wood cakes and coal cakes (some models only).
The moisture of the wood to be burnt should be lower than 20%, optimally 10%. The rule of
thumb is: the less water in the fuel, the higher heating capacity you achieve. For the
recommended wood moisture, you may reach it safely if you store the wood in a well
ventilated shelter for at least two years. The water content in coal cakes should be
specified by the manufacturer. The cakes should be stored in a dry room otherwise they
disintegrate. It is recommended to store the wood intended for burning in pieces approx. 3-
6 cm (diameter), 20–30 cm (length). It is forbidden to load and burn coal or charred
coal. In the fireplace, never burn flammable liquids or waste. It is forbidden to burn
papering, chipboards, plastic materials, penetrated wood, wood shavings or saw dust.
Burning such materials not only is detrimental to the environment but shortens the service
life of the heating device as well: you might seriously damage the device or the chimney as
well.
Note: The bark, a part of wooden logs, is no issue at all.
Fuel efficiency: selected types of wood at moisture 20%
Wood Fuel efficiency
kWh/m3
Fuel efficiency
kWh/1 kg
Weight kg/(m3)
Spruce, fir 1957 4,0 485
Larch 2461 4,0 610
Pine 2280 4,0 565
Oak, beech 2743 3,8 726
Chart 2
3. SAFE OPERATION
3.1. General requirements
While installing and operating stove (stove insert), it is obligatory to adhere to the fire
prevention regulations (related to this type of devices) in force in the country of
installation.
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