KENWOOD - K714WM14 Waste pipe

[sonordrummer]

Hi, 

recently we have been having issues with our washing machine draining. I've checked the filter and that was clean. The next thing I checked was the waste pipe that fixes on to the sink outlet. 

There seems to be a small black object stuck in the pipe. When I move this slightly it allows the machine to drain. What I am not sure about is if this is meant to be in the pipe or not. Is it some sort of non return? 

Im hoping someone can let me know what it is. I have attached an image that shows the object in the pipe. 

Thank you

[Whitegoodshelp]

Yes it must be a non-return valve. Make sure it's all clean around and under it so it isn't sticking.