Frost protection strategies

Icing of the heat exchanger is prevented by monitoring the outgoing air temperature and reducing the outside air volumetric flow rate in case of danger of frost. This is regulated using a calculated outgoing air temperature (e.g. 4 °C). If a frost hazard is detected, the outside air volumetric flow rate is gradually reduced to 20 m³/h. If this is not possible, the outdoor air fan is switched off.