During the further development of our “classic line i” series, the focus was on noise reduction and energy efficiency. This resulted in one of the quietest heat pumps on the market that produces noise emissions of only 22-36 db(A) in partial load operation. Designed as a 3-season heat pump, the machine modulates in different output ranges depending on the heat requirement. This way, the “classic-line i” heat pumps achieve a high COP value in partial load operation and pleasantly low noise emissions. However, should a noise problem occur during operation, the “classic-line i” models, up to the output size 180, provide the facility to subsequently regulate the power output and therefore the noise level on site. The “classic line i” product range includes 6 output sizes ranging from 11 to 30 kW. The output-controlled operating mode and standard hot gas defrosting, which is pressure and temperature-controlled in contrast to other systems, ensure safe operation, even when outdoor temperatures are slightly colder. The integrated digital control unit permits a combination with other energy sources and enables the fully automatic heating and cooling of your pool. The control unit can also be operated from your equipment room with an optionally available control panel. It is also possible to heat very large pool areas by interconnecting several “classic line i” models in a cascade.