Method for operating a pump

A pump of a dishwasher has an integrated heating element, a pump chamber with an inlet and an outlet, a pump rotor inside the pump chamber and a drive motor, wherein the heating element and a temperature sensor are provided on a wall of the pump chamber. For measuring a calcification of the pump chamber it is filled with water and then the pump rotor rotates for mixing the water in the pump chamber without transporting water out of the pump chamber. The temperature of the water in the pump chamber is measured with the temperature sensor as a starting temperature, and then the heating element is activated to heat the water in the pump chamber while the temperature of the water in the pump chamber is measured. Then the heating element is deactivated and the maximum temperature of the water during the heating duration or directly afterwards is determined. A temperature relation between the maximum temperature and the starting temperature of the water is calculated. These steps are executed in the pump at the very beginning of an operation of the new dishwasher after its installation for determining an initial temperature relation. These steps are automatically executed again at a later stage for determining a later temperature relation to determine the heating efficiency of the pump by comparing the later temperature relation to the initial temperature relation.