1.The heat pump is not heating / has lost power:

As the temperature difference between the pool water and the surrounding air increases, there are greater heat losses at the surface of the pool. Even a covered pool with an uncovered surface experiences significant heat losses – the space under the enclosure is "heated" by the water surface. This, in turn, places higher demands on the heat pump.

Furthermore, the efficiency of the heat pump is lower when the outdoor air temperature is lower.

Example:

Heat Pump Rapid Inverter (565RIC040)

• At an air temperature of 26 °C and a humidity of 80%, the heat pump has a heating capacity of 15 kW and a COP of up to 16
  
• The same pump, however, at an air temperature of +5 °C only has a heating capacity of approx. 7 kW and a maximum COP of 6.
  
• At a temperature of -5 °C the heating capacity is only 5.5 kW with a maximum COP of just over 4.

The heat pump does provide heating, but at lower output in colder conditions, it may not be able to cover the pool's heat loss. This can result in a drop in the pool's temperature by more than 2°C overnight. In practice, this means that the heat pump heats the water by 2°C during the day, but it is "lost" again overnight.

For the customer, this combination can create the impression that the heat pump is not heating or not functioning properly.

    2.The heat pump "burns"/steams or freezes:

Due to the drop in the surrounding air temperature below 12°C and high air humidity, condensation freezes on the evaporator of the heat pump. For this reason, heat pumps have an automatic "defrosting" mode in which the hot refrigerant bypasses the heat exchanger. Instead, thanks to a 4-way automatic valve, it is directed straight into the evaporator, leading to an immediate "thawing" of the frost.

Steam rises from the heat pump during the defrosting process - it does not smoke.

Automatic defrosting is a feature found only in mid-range or higher-end heat pumps. This function allows the heat pump to operate even at low temperatures.