Defrost settings

This section describes making the following defrost-related settings:

  • 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.
  • Airflow temperature — The supply air temperature setting determines the temperature of supply air when bypass defrosting is enabled. The temperature can be adjusted between 12°C and 20°C (factory setting 15°C). In severe frost, if the heating resistor is not powerful enough, the ventilation unit will allow the supply air temperature to drop to a maximum of 12°C.
  • Defrosting sensitivity — The sensitivity of the defrosting function affects how easily the ventilation unit start to defrost the HR cell.
  1. Open Expert settings and select Defrost settings.
  2. Defrosting methods:

    • Bypass (factory setting) — The HR cell is bypassed on the supply air side. The supply and extract air fans operate normally and the ventilation balance remains unchanged during defrosting. This prevents drafts or air leaks caused by differences in pressure.

      This is the recommended setting, especially for airtight buildings where negative pressure can cause problems. When bypass is used, the ventilation unit’s post-heating resistor and any additional heating resistor must be in use.

    • Stopping the fan — The supply air fan is stopped for the duration of the defrosting period. The apartment becomes temporarily depressurised. This setting should be used if the indoor air temperature is abnormally low (<15°C) or to reduce the use of heating resistors during defrosting.
    Important:
    There is usually no need to change the defrosting settings. For normal living conditions, the factory settings are sufficient. In exceptional situations, such as in pool facilities or situations in which the accumulation of ice in the exhaust air duct becomes harmful, the settings may need to be adjusted.
    • Defrosting sensitivity — The optimum value is 0, which balances the need for defrosting with the performance of the cell. Lowering the value will cause the unit to defrost more often, which will help prevent the cell from freezing. Increasing the value decreases the frequency of defrosting, which increases the risk of the cell freezing, especially in cold conditions.
    • Airflow temperature — The supply air temperature setting during bypass defrost. You can adjust the temperature between +12°C and +20°C. The factory setting is 15°C.