Patent 7146670 was granted and assigned to Fisher & Paykel on December, 2006 by the United States Patent and Trademark Office.
A method of operating a drain pump in a laundry washing machine during the drain phase of the wash cycle to reduce pump blockages is disclosed. The method includes the steps of (a) starting the pump and running it for a first period of time to produce a discharge of a given flow rate, (b) stopping the pump and leaving the pump stopped for a second period of time, and repeating steps (a) and (b) for the duration of said drain phase, said second period of time being such that the flow rate reduces substantially to zero.