Electrical continuous-flow heater comprising: a first end channel, namely a water inlet channel with an inner channel end and an outer channel end opening into a first outer channel opening, a first pipe connection piece which sits in detachable sealing connection in the first outer channel opening, namely in a sealing seat, and is configured for connection to a first outer water pipe supplying water, a second end channel, namely a water outlet channel with an inner channel end and an outer channel end opening into a second outer channel opening, a second pipe connection piece which sits in detachable sealing connection in the second outer channel opening, namely in a sealing seat, and which is configured for connection to a second outer water pipe receiving water, a channel arrangement of water-conducting channels (41, 42, 43, 44) between the inner channel ends (22, 32) of the end channels (2, 3), an electrical heating device configured to heat water flowing through the channel arrangement, an electrical control device for controlling the temperature of the heating device, and a flow metering device which detects the quantity of water supplied to the heating device and provides the electrical control device with a flow control signal established according to the flow quantity, wherein the flow metering device comprises a flow meter inserted in the water path of the channels, and a sensor emitting the flow control signal and responding to the flow meter contactlessly and without touch, characterized in that the flow meter is configured as a flow meter insert part, that a flow meter insert space is formed in at least one of the two end channels (2, 3) and is configured to receive completely the flow meter insert part, wherein the flow meter insert part is insertable from the outer channel end, when the pipe connection piece is removed, through the outer channel opening into the end channel, and that the flow meter insert part is inserted by a detachable seat in the insert space, wherein it is arranged in series with the pipe connection piece which in its said sealing seat is removable from the outer channel opening. a first end channel, namely a water inlet channel with an inner channel end and an outer channel end opening into a first outer channel opening, a first pipe connection piece which sits in detachable sealing connection in the first outer channel opening, namely in a sealing seat, and is configured for connection to a first outer water pipe supplying water, a second end channel, namely a water outlet channel with an inner channel end and an outer channel end opening into a second outer channel opening, a second pipe connection piece which sits in detachable sealing connection in the second outer channel opening, namely in a sealing seat, and which is configured for connection to a second outer water pipe receiving water, a channel arrangement of water-conducting channels (41, 42, 43, 44) between the inner channel ends (22, 32) of the end channels (2, 3), an electrical heating device configured to heat water flowing through the channel arrangement, an electrical control device for controlling the temperature of the heating device, and a flow metering device which detects the quantity of water supplied to the heating device and provides the electrical control device with a flow control signal established according to the flow quantity, wherein the flow metering device comprises a flow meter inserted in the water path of the channels, and a sensor emitting the flow control signal and responding to the flow meter contactlessly and without touch, characterized in that the flow meter is configured as a flow meter insert part, that a flow meter insert space is formed in at least one of the two end channels (2, 3) and is configured to receive completely the flow meter insert part, wherein the flow meter insert part is insertable from the outer channel end, when the pipe connection piece is removed, through the outer channel opening into the end channel, and that the flow meter insert part is inserted by a detachable seat in the insert space, wherein it is arranged in series with the pipe connection piece which in its said sealing seat is removable from the outer channel opening.