What is defrosting by circuit reversal?

Ice can form on the evaporator of air to water heat pumps in certain operating conditions. It forms in this way: Heat is extracted from the air in the evaporator. If the air temperature falls below the dew point in this process, then condensate is created, which freezes into ice at temperatures between -5 and +7 °C. Important: The evaporator must be defrosted regularly, so that the heat pump can continue to operate efficiently.

Icing up of the evaporator is monitored continuously by the internal control unit and the process of defrosting by circuit reversal can be initiated fully automatically when required. In this situation the refrigerant circuit of the heat pump is operated in the opposite direction by means of a diverter valve. This draws heat temporarily from the water in the buffer cylinder or underfloor heating system and transfers it to the evaporator. The ice melts and drains off as condensate – efficient operation is ensured.