System for detecting drainage flow obstructions in washing appliances

摘要

A method of monitoring drainage of a washing appliance such as a dishwasher 108 or washing machine 102 having a pump for draining a washing chamber is disclosed. The method includes receiving a time series of power consumption data relating to the operation of the washing appliance over a monitored period of operation including pumped draining of the washing chamber. A measure of the duration of a portion of the monitored period comprising said pumped draining is derived from the time series of power consumption data. The measure of duration is then compared to a reference value and an indicator of a drainage condition is determined based on the comparison. The method may be used to detect scaling or blockages in drainage flow paths. A method of monitoring drainage of first and second washing appliance connected to a common drainage outlet is also disclosed.