Using The Sauna Heater; Firewood; Heating; Heating Of The Sauna - KOTA Kuru series Installations-, Betriebs- Und Wartungsanleitung

4. Using the sauna
heater

4.1 Firewood

Only use natural wood logs as fuel. Both hardwood and
softwood can be used to heat the sauna heater. The use of
chipboard, fibreboard, briquet, pellet, painted or impreg-
nated wood, waste or plastic is prohibited. To ensure clean
burning and the largest possible efficiency, the wood must
be dry. The moisture content of the wood must be less
than 20%. Usually good firewood is sticks of wood the
diameter of which is around 5 cm, length around 33 cm
and weight around 0.5 kg.
Use of liquid fuel is strongly forbidden, also during firing!

4.2 Heating

Before heating, make sure that there is no combustible
material within the safety clearances. Also make sure that
the ash drawer and fire grate are clean and if the sauna
heater is provided with a water tank, that it is filled with
clean water. Check if there is sufficient draft in the smoke
flue. If you hesitate regarding the draft, check it by burning
a small quantity of water in the firebox first. During heating
the door of the firebox must be closed and the water tank
must be filled with water. The sauna heater must not be
covered with anything.
To start heating pile firewood over a sufficiently wide area
and ignite it from above. For ignition you may use birch
bark or paper. Ignition aid should be placed between the
upper firewood and it can be topped with some thinner
wood sticks or firewood (see drawing 9). Igniting from
above reduces pollution and ensures cleaner burning.
Figure 9. Properly stacked firewood.
The power of the sauna heater can be regulated by the
ash drawer. In case of this sauna heater opening of the ash
drawer is limited. When the door is closed, the ash drawer
opens approximately 10 mm, which is a suitable position
to ignite the fire and for heating. If it soughs too much in
the sauna heater, reduce the draft. To do this close the ash
drawer halfway or completely. This way heat reaches bet-
ter in the sauna heater, stones can store heat and you do
Yrittäjäntie 14, FI-27230 Lappi • tel. +358 0207 416 740 • fax +358 0207 416 743 • www.narvi.fi/en
Figure 9.
not just heat up the flue. A calm flame is a sign of a correct
draft. Avoid heating the sauna heater so that the chan-
nels of the stone compartment glow red for a long time
because this will overload the firebox and the service life
of the sauna heater will be reduced. Overheating may also
cause excessive heating of the smoke flue and cause a fire
hazard. The connective flue pipe must not be glowing red.
The following table shows the recommended quantities
of firewood for different types of sauna heaters and po-
sitions of the ash drawer. The values shown in the table
meet the values of the nominal power pursuant to standard
EN15821. In the test the size of the sauna was determined
based on the maximum area for the given sauna heater
and temperature of 90 °C was achieved in the sauna. Dur-
ing first times we recommend using less firewood for
achieving the desired temperature than values present-
ed in the table. Maximum quantity of firewood per hour
(max kg/h) indicated in the table must not be exceeded.

Heating of the sauna:

Kuru sauna heater
1. . firebox of firewood*
quantity of firewood (kg)
1. addition
quantity of firewood (kg)
2. addition
quantity of firewood (kg)
max kg/h
*) Sticks of firewood with a diameter around 5 cm, length
around 33 cm and weight around 0.5 kg.
Do not stack firewood in the firebox over 2/3 of its height.
Quantities of firewood are shown in clause 4.1.
In a sauna heater equipped with a water tank or in a sauna
heater that is heated from another room firewood should
not be burnt in the front part of the firebox / in the exten-
sion, but the firewood must be placed entirely on the grate
of the firebox.
Do not forget that the sauna heater and its part become
very hot during heating. Always use gloves or other
hand protection when being in touch with the parts of
the heater. When moving around in the sauna be careful,
because the floor and the ceiling of the sauna may be
slippery.
Be careful – water in the water tank of the sauna
heater may be very hot.
14 20
3,5 4
2 3
2 3
6 7,5
25 GB