The defrosting method is applied by the unit when the heat recovery cell must be defrosted. The heat recovery cell is defrosted using the heat recovered from the extract air, or by bypassing the heat recovery cell from the outside. The duration of the defrosting cycle is 15–45 minutes depending on the amount of ice. Defrosting is part of the normal operation of the unit in winter.
There are two defrosting methods:
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Bypass — If the Bypass is selected as the defrosting method, the heat recovery cell will be bypassed on the supply air side. This does not change the ratio between the supply and extract air fans.
In the Bypass state, the electric resistor heats the cool air streaming in from outside to the set temperature for the duration of the defrosting cycle. If the set temperature is too relative to the outdoor temperature, the unit reduces the supply and extract air flows to achieve the set supply air temperature.
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Supply fan stop — If Supply fan stop is set as the defrosting method, the supply air fan will be stopped for the entire defrosting cycle. A momentary underpressure is created in the apartment.
Important
The parametres need not be changed in normal living conditions. Exceptional conditions include high moisture loads caused by e.g. pool premises, or the accumulation of a problematic amount of ice in the exhaust air channel.
To set the defrosting method:
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Select Settings:
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Use the arrow buttons to select Expert settings:
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Select OK:
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Use the arrow buttons to select Defrost settings:
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Select OK:
The Defrost settings display opens:
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Use the Plus and Minus buttons to select the defrosting method.
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Select OK:
The defrosting method is now set.