Defrosting method

The HR cell is defrosted when ice has accumulated in the cell. The selected defrosting method determines how the defrosting is done. The defrosting process takes about 15–45 minutes depending on the amount of ice. It is normal for the unit to defrost the HR cell in winter.

The defrosting methods:

  • Bypass (factory setting) — The HR cell is bypassed from the supply air side. The supply and extract air fans function normally, and the ventilation balance remains constant during defrosting. This prevents drafts or air breaks caused by differences in pressure. This setting is recommended for tightly sealed buildings that may experience negative pressure. When the bypass function is used, the ventilation unit’s post-heating resistor and optional additional heating resistor must be activated.

  • Supply fan stop — The supply air fan stops during defrosting. This causes temporary negative pressure in the apartment. This setting is recommended if the indoor air temperature is exceptionally low (<15°C) or if you want to reduce the use of the heating resistors during defrosting.

Important:

It is usually not necessary to adjust the defrosting settings. The factory settings suffice in normal household use. In exceptional situations, for example, in indoor pool facilities or when a great amount of ice accumulates in the exhaust air duct, the settings could be adjusted.

To set the defrosting method:

  1. Select Settings:
  2. Open Expert settings and select Defrost settings.
  3. Select a defrosting method.
    Note:
    If post-heating and additional heating is not used, the fan is automatically stopped for defrosting and no other defrosting method can be selected.