A method of operating a water-circulating household appliance , the water-circulating household appliance comprising an electric motor and a washing liquid circuit , the washing liquid circuit comprising a pump for circulating washing liquid through the washing liquid circuit , a portion of the washing liquid circuit being arranged in thermal communication with the electric motor , wherein the electric motor has a first direction of rotation and a second direction of rotation and is arranged to drive the pump , and wherein the pump has a primary direction of rotation corresponding to the first direction of rotation of the electric motor , and the method comprises a step of driving the electric motor , with a higher electrical power input than required for circulating the washing liquid through the washing liquid circuit with the pump rotating in the primary direction of rotation, characterised in that : the step of driving the electric motor is over a time period longer than 1 minute; and the step of driving the electric motor comprises a step of causing an excessive electrical loss in the electric motor exceeding a normal electrical loss in the electric motor associated with rotating the pump in the primary direction for circulating the washing liquid through the washing liquid circuit , wherein the step of causing the excessive electrical loss comprises a step of repeatedly starting and stopping the rotation of the electric motor a number of times during each of a number of consecutive 1 minute time periods; or wherein the step of causing an excessive electrical loss comprises a step of sending a DC voltage into at least one set of windings of the electric motor ; or wherein the step of causing the excessive electrical loss comprises a step of sending an out of phase AC voltage through at least one set of windings of the electric motor . the step of driving the electric motor is over a time period longer than 1 minute; and the step of driving the electric motor comprises a step of causing an excessive electrical loss in the electric motor exceeding a normal electrical loss in the electric motor associated with rotating the pump in the primary direction for circulating the washing liquid through the washing liquid circuit , wherein the step of causing the excessive electrical loss comprises a step of repeatedly starting and stopping the rotation of the electric motor a number of times during each of a number of consecutive 1 minute time periods; or wherein the step of causing an excessive electrical loss comprises a step of sending a DC voltage into at least one set of windings of the electric motor ; or wherein the step of causing the excessive electrical loss comprises a step of sending an out of phase AC voltage through at least one set of windings of the electric motor . wherein the step of causing the excessive electrical loss comprises a step of repeatedly starting and stopping the rotation of the electric motor a number of times during each of a number of consecutive 1 minute time periods; or wherein the step of causing an excessive electrical loss comprises a step of sending a DC voltage into at least one set of windings of the electric motor ; or wherein the step of causing the excessive electrical loss comprises a step of sending an out of phase AC voltage through at least one set of windings of the electric motor . <EOS>