temperature is reached the heat pump is turned off automatically, it comes back in operation only if the pool temperature is dropped by 1 degrees less than the set temperature. All our heat pumps have the best of inverter technology which allows it to drop to a lower speed and higher efficiency, maintaining an efficient heating process while avoiding consuming excess power. You may notice a reduction of the fan speed once the heat pump displays the set temperature this is how it maintains a perfect swimming temperature whilst your filtration pump is running.