HUUM DROP Manuel D'installation Et D'opération page 10

Darkening of the sauna room walls
Due to heat, the wood material in the sauna room darkens in time.
If you use wood protection products, you may notice that the wall
above the heater darkens before long. The darkening process is also
caused by the fine stone dust, breaking away from the heater stones
and lifted up by the airflow. If you follow the producer's instructions
upon installing the heater, the flammable materials in the sauna room
will not heat to a dangerous level. The highest allowed temperature
for the wall and ceiling surfaces is 284 °F (140 °C).
Floor of the sauna room
The heater stones in use crumble due to temperature changes.
The pieces and pebbles breaking away from the heater stones are
washed on the sauna's floor with the steam-making water. Hot stone
parts may damage plastic flooring under and near the heater.
Heater stone particles and sprays from the steam-making water (e.g.,
with iron content) may absorb into the light joints of a tile floor. In
order to avoid aesthetic damage (caused by the reasons mentioned
above), ceramic tiles and dark joint filler should be used under and
around the heater.
Ventilation of the sauna
In order to assure a sufficient oxygen supply and fresh air, the sauna's
ventilation must be as efficient as possible. It is advisable to direct
the fresh air into the sauna room from above the heater stones. As an
alternative, the fresh air may be directed in from under the heater.
The air inlet must be equipped with an adjustable valve. The exhaust
valve must be installed in the opposite wall from the heater at least
7.9 in (20 cm) above the inlet valve.
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