The i nner space o f the firing c hamber is u sually lined w ith fireclay b rick shapes. T he brick s hapes
are not jointed w ith any filler (the reason i s a protect ion of the brick s against damage b y t hermic
dilatation). The upper part of the firing chamber is equipped w ith partitions designed for directing
flue gases into a smoke outlet. The partitions may be fixed or movable. Such movable partition may
serve as a s upporting h older f or f ireclay b rick s hapes. At the bottom part of the firing c hamber, a
simple, fixed c ast grate i s installed. B efore the grate, a barrier is usua lly provided, t o prevent f rom
burning pieces falling out or onto the door (front glass). Under the grate, there is a space designed
for ashpan. The r emaining space at t he bottom part o f the s tove may be u sed for spare f uel. With
certain models, the smoke flue neck may be adjusted for upper or rear outlet of the smoke: you just
release the clamps and r otate the neck of t he smoke flue set in the required direction.
The fireplace insert ma y be a si ngle- or t win-shell model. The twin-shell type is designed to provide
direct support to the convective stream flowing through the outer construction of the insert body. The
convection holes at the bottom part of the insert allow the air inlet in-between the insert and the
casing. The steel constructio n of the fireplace insert is protected with special refractory paint.
Caution! Fireplace inserts are not designed for continuous heating but for periodical –
interrupted (i.e. temporar y) operation.
2. FIRING PROCESS
2.1. Fuel quantity and f iring process adjustm ents
Burning wood, wood cakes (or coal cakes – optional) in fireplace inserts 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 al ways
adjustable. B y increasing temperat ure o f t he fuel b urning through, cert ain g aseous c omponent s of
the fuel evolve that – unless additional air is supplied – would b e 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, w hile secondary air supply is required, or tertiary air may be adde d as w ell,
respectively. The secondary air supply, usually adjustable, improves the firing process and
contributes to the door gla ss self - cleani ng. The tertiary ai r supply is designed for general
improvement of the burning process and is usually fixed (one cannot regulate it anyhow). If the
proportion of the air vol umes led into the p articular sections of the firing ch amber is correct, the
burning efficiency is i ncreased while emission of pollutants in the environment is reduce d. The
layout o f the air s upply regul ative e lement s i s s hown in the T echnical C ard ( a p art o f t he
documentation supplied w ith the fireplace insert ).
The heating capacity of the heating device depends on the fuel quantity burnt per defined time, fuel
quality and firing pr ocess efficiency. The dat a shown in C hart 2 ( heating values) may h elp you to
make a pi cture of attainable capacity: let’s assume that you burn 1 kg of wood per hour, wood
moisture is 20%. Further , with higher wood moisture its heating capacity goes down.
In t he t esting r oom conditions, adjustabi lity o f t he h eating device was tested, within 30 – 1 00% of
nominal performance. For the regulation, the chimney effect and the fuel quantity were applied. In
practice, the h eat ing capacity ma y be regulated b y means of ai r supply regulating e lem ents
(especially the primary air inl et). There i s no simple and explicit way to determine the firing process
adjustment by means o f r egulators. There are m any aspect s t o 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 part icular conditions.
You will be able to adjust the firing process to achieve best efficiency after a s hort time of operation.
A detailed chart showing how to adjust the air s upply regulating elements is included in the Technical
Card. T he figures in the c hart are the testing results verified b y the State Testing L aboratory. 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
and eco-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 w ood is dry, maximum m oisture 20%.
Our tips for coal cake burni ng (selected models only)
• To achieve optimisation of the firing process, load the cakes dir ectly onto the grate holes: t his
way, you support the burning in best possible w ay.
• 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 c ake
fuel efficiency may reach 6 kWh/1 kg, i.e. by some 40% more t han wood!
2.2. Fuel
For fireplaces, 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 st ore the w ood in a well v entilated shelt er for at le ast two y ears. The w ater
content in coal cakes should be specified by the manufacturer. T he 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 f ireplace, 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 t ypes of wood at moisture 20%
Wood Fuel efficiency
kWh/m
3
Fuel efficiency kWh/1
kg
Weight kg/m
3
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 OPERA TION
3.1. General requirements
While installing and operat ing stove insert, it is obligatory to adhere to the fire prevention
regulations (related to t his type of devices) in force i n the country of inst allation.
The device is designed for standard environment. In case of any temporary change establishing any
temporary dan ger of fire or explosion (for example, while i nstalling linoleum flooring, PVC, painting,
etc.) it is crucial to put the heating device out of operation IN TIME, BEFORE ANY POTENTIAL
DANGEROUS SITUATION MAY O CCUR. A t the e nd of t he work, d o not start using the fireplace
again until the room conditions are brought back to normal (it is recommended to provide fresh air by
draught).
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