The invention relates to a peritoneal dialysis appliance for carrying out peritoneal dialysis treatment with recurring cycles, the cycles comprising a fill phase, a dwell period and a drain phase for the dialysis liquid, wherein the appliance has a control unit and a measurement device for determining the filling and/or drainage behaviour of the dialysis liquid from a patient, wherein the control unit is configured, on the basis of the measured values collected over several fill and/or drain phases, to determine a delay factor which sets a theoretical fill and/or drain duration in relation to the actual fill and/or drain duration of dialysis liquid to/from the patient.
