Fitting non return valve

[cheddarman]

The discharge hose from our washing machine comes out of the machine, runs about five feet along the floor under the work surface and then goes vertically up under the sink where it joins the sink discharge pipe.

Every time we empty the sink, the water often goes back down the hose and even fills the washing machine drum!

Ho can I prevent this. Presumably fit a non return valve somewhere in the discharge line, but where would be the best place and which valve would be appropriate?

Thanks

 

[ShaunCorbs]

Raise the tube to the under side of the worktop and clip it so it stays there

 

[cheddarman]

Raise the tube to the under side of the worktop and clip it so it stays there

Umm, not really possible as that work area contains a large drawer unit and an electric hob, but I'll have a look. Thanks

 

[John.g]

You could possibly install a swing check valve with a rubber seat on the horizontal with it leaning back a little towards the wash machine, also ensure the discharge where it joins the sink drain is clear, also the whole sink down section and any trap.