In the hydro-box, water is heated in the plate heat exchanger by transferring the thermal energy obtained from the outdoor unit. The heat energy carrier is R410a refrigerant. In this way, the water temperature can be up to 55 ° C. Besides the plate exchanger, the hydro-box also includes a heating circulation pump, an expansion vessel, a controller and an auxiliary electric heater. The integrated control system controls all valves, pumps and other parts of the system, eg those that ensure the full operation of the heating system at very low temperatures (eg the TCB-PCIN3E gas boiler). If necessary, the Toshiba heat pump can be controlled from other control systems (eg higher control system or other DHW cylinder thermostat - TCP-PCM03E module required).