Flow drinking water heater, system for heating drinking water and method for operating a flow drinking water heater

摘要

The invention relates to a flow drinking water heater with a first heat exchanger (4), second heat exchanger (6), a primary line arrangement (8), a secondary line arrangement (10), the primary line arrangement (8) connecting the primary sides of the heat exchangers (4, 6) in series, wherein the secondary line arrangement (10) connects the secondary sides of the heat exchangers (4, 6) in series and connects the cold water line (18) through the second heat exchanger (6) to the secondary side inlet of the first heat exchanger (4) with a first pump (20 ), with a second pump (22), with a first temperature sensor (24) arranged in the secondary line arrangement (10) and with a control device (26) for detecting the measured values of the temperature sensor (24) and for controlling the first pump (20) and the second pump (22). The control device (26) is set up to regulate the pumping capacity of the first pump (20) to a predetermined secondary return temperature of the first heat exchanger (4), so that the control device (26) is set up to activate the pumping capacity of the second pump (22). if the required total heat transfer capacity exceeds a predetermined limit heat transfer capacity of the first heat exchanger (4) and that the control device (26) is set up to deactivate the pump capacity of the second pump (20), if the required total heat transfer capacity exceeds the predetermined limit heat transfer capacity of the first heat exchanger (4) falls below.