Circulation controller in wall mounting housing with controller adjustment via menus. A flow switch connected to EC 1 (for example, circulation switch ZS 2) monitors water withdrawal at the hot water end. After short opening of a tap in the hot water line, the circulation pump is switched on and stopped after an additional running time adjusted by the user has elapsed. This turns any standard fitting in the hot water system into a kind of "remote control".
This is energy savings in two ways: due to the demand-controlled pump, the storage tank is not cooled down unnecessarily by circulating the hot water, and the shorter running time of the circulation pump saves energy.