Abstract: Consumers often complain that their washing machine does not drain, it accounts for a sizable proportion of all complaints. The problem is caused by three factors: pump damaged, pump blocked and gas trapped in the pump. The pump damaged and pump blocked mainly as a result of incorrectly plugged, the pump impeller was damaged by foreign matter and the impeller got stuck; and trapped gas mainly due to structural design or software beats’ unreasonable. This paper optimized and adjusted software, through the drainage pump terminal foolproof, door seal clearance control, increased filter screen, pressure difference, natural backwater, no vacuum, resolve the drainage issue.

Key words: Washing machine does not drain, Gas trapped in pump, Pump blocked, Structural configuration, Software logic