Defrost settings

This section describes making the following defrost-related settings:

  • Defrosting method — The defrosting method is the method the unit uses to defrost the frozen HR cell. The HR cell is defrosted with heat from extract air or by having outdoor air bypass the HR cell. 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.
  • Internal %RH — The relative humidity of indoor air affects the frosting of the HR cell significantly. The unit is designed to operate optimally in normal humidity conditions of residential buildings. If the unit has been installed in exceptional humidity conditions, such as pool facilities, the relative humidity of air coefficient may need to be manually adjusted. Set the humidity percentage above zero in humid conditions and below zero in dry conditions.
  • Outdoor air °C — The outdoor air temperature parameter can be used to control the operation of the unit in very cold conditions below -20°C when using an aluminium cell and below -5°C when using a plastic cell). The parameter has been optimised based on the cell type used and the installation conditions.
    Important:

    The outdoor air temperature setting must only be changed in extreme situations, and with the help of a HVAC specialist. If the HR cell becomes frozen, the temperature value must be lowered. We do not recommend that the value be increased under any circumstances.

To configure the aforementioned settings:

  1. Select Expert settings.
  2. The defrost settings are described in the Defrost settings area.
  3. Select one of the following defrosting methods from the Defrosting method drop down menu.

    • HR cell bypass — In this defrosting method, the HR cell is bypassed from the supply air side. The ratio of the supply and extract air flows does not change. In some cases, this can prevent harmful underpressure from forming in the apartment.

      In this defrosting mode, the electric resistor heats the cold air flowing in from outside to the target temperature during the defrosting period. If the target temperature is high compared to the outdoor air temperature, the unit reduces the supply and extract air flows to achieve the target supply air temperature.

    • Stopping the fan — In this defrosting method, the supply air fan is stopped for the duration of the defrosting period. The apartment becomes temporarily depressurised.
    Important:

    It is not necessary to adjust the parameters under normal living conditions. Exceptional conditions include, for example, spaces with large humidity loads, such as pool facilities, or situations in which the accumulation of ice in the exhaust air duct becomes harmful.

    The defrosting method is now set.
  4. Set the relative humidity of air by moving the blue Internal %RH slider to the desired value.

    The relative humidity of air value can be set between -50% – +50%RH.

  5. The relative humidity of indoor air is now set.
  6. Set the outdoor air temperature by moving the blue Outdoor air °C slider to the desired value.

    You can set the value between 0–100%. The factory setting depends on the type of ventilation unit.

  7. The outdoor air temperature is now set.