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GENERAL
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SPECIALIS
T PERSONNEL
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KWL
®
Hygrobox KWL HBX EH/WW
Operating and installation instructions
12
8. Functional description
8.1. Working principle
The air humidification unit is operated in connection with an air conditioning and ventilation system. The installation is carried out
directly downstream of the living space ventilation unit in the supply air duct.
The air humidification unit works according to the principle of natural evaporation. When entering the air humidification unit, the sup-
ply air flows through a heater battery first. If required, it is heated first, however, the absolute humidity of the air remains constant.
Then the air flows via specially coated rotor blades that are wetted with water. This water is absorbed by the air by evaporation (adia-
batic humidification) and the absolute air humidity increases. At the same time, the evaporation process causes a decrease in the air
temperature; the relative air humidity increases.
The air humidification unit is not suitable for heating the supply air, the heater battery mainly serves to supply energy for the evapo-
ration process. Neither can the unit be used for purposes of cooling. Temperature regulation is subordinate to air humidity regulation.
The adjustable air temperature at the outlet of the air humidification unit is between 15 °C and 25 °C. The adjustable relative air
humidity is between 40 % and 60 %. Whether these target values are actually achieved always also depends on the condition of the
air when it enters the air humidification unit.
The unit works automatically, the humidity in the unit is monitored electronically. Excess humidity of the supply air is therefore ruled
out.
The KWL HBX 250 air humidification unit is dimensioned for a maximum operating air volume flow of 350 m³/h, the KWL HBX 500 for
a maximum operating air volume flow of 500 m³/h.
Note:
The air humidification unit must not be operated with a higher air volume flow as the one specified in this operating instruc-
tion. If the maximum operating volume flow is exceeded, individual water drops can be carried along at the outlet of the air
humidification unit. In this way, water may enter the supply air duct!
The humidifier tank is supplied with drinking water from the central water supply. In order to minimise deposits on the rotation
lamellae and in the water tank during operation, the air humidification unit comes with a standard reverse osmosis unit. The reverse
osmosis unit is integrated into the water supply line between the solenoid valve and the water tank. A pre-filter unit in the form of a
water filter, which is to be integrated (externally) into the water supply line in the framework of the installation process, is included in
the scope of supply.
Depending on the evaporation performance, the humidifier tank contains a maximum of 2.5 litres of water (KWL HBX 250) and a
maximum of 6 litres of water (KWL HBX 500). Evaporated water is replaced permanently by fresh water. In addition, the water is com-
pletely replaced on a daily basis for hygienic reasons. The maximum water level is limited by means of a float switch. Overflowing of
the tank is additionally prevented by an overflow drain.
During humidification operation, the water in the tank is continuously irradiated and disinfected with UVC light, the UVC tube com-
pletely illuminating the water tank and evaporation surfaces. For reasons of safety, the UVC tube is actuated with a ballast with an
integrated error detection function. If the UVC tube is defective or the maximum operating hours of the UVC tube have been reached,
the water in the KWL HBX 250/KWL HBX 500 is drained and a fault message is output.
8.2. Reverse osmosis
The water pressure in the drinking water pipeline allows for the operation of the reverse osmosis unit. In this process, the untreated
water (drinking water) is pressed through a semi-permeable osmosis membrane. The pure water passes through this membrane
(however, not back again) and afterwards into the humidifier tank. The residual water with all the substances dissolved in the water
(e.g. nitrate, nitrite, germs, lime, …) is led to the drain. While the filling process is taking place, residual water is also always drained at
the same time.
8.3. UVC disinfection
The water in the humidifier tank is disinfected by means of UVC radiation, killing germs and bacteria and preventing their growth.
The UVC disinfection offers the advantage of being a non-chemical treatment type that does not pose any hazard to health (no ozone
production possible!). Irradiation exclusively takes place in a closed area with a radiation performance of 4.3 watts at a wavelength of
253.7 nm.
When carrying out maintenance and repair work, never look into the illuminated UVC tube without eye protection!
Only operate the UVC tube in a closed housing that is not damaged.
