The heat pump manager WPM is the main controller in the system. The built-in control unit controls one direct and two mixed heating circuits. In addition, two heat pumps can be used in cascade. In combination with the Internet Service Gateway (ISG), the heat pump can be integrated into a home network or controlled via mobile terminals. The direct connection of highly efficient circulation pumps is possible via relay outputs or PWM outputs. In addition, the WPM offers a fault contact to externally detect installation faults. In the drip-resistant wall housing with large installation space, the electrical installation and other components, such as a mounting rail relay, have sufficient space. The sophisticated cable routing makes the connection easier.