Hi there! We're tearing out our hair here: We've just fitted a non-return valve into the outlet hose between the washing machine and u-bend. This has been secured with jubilee clips. Prior to this, foul water was entering the sink, due to a blockage which has now been cleared. Unfortunately, when we put the washing machine on, thinking the problem had, at last, been cured, we discovered that the connection between the hose and non-return valve is leaking badly. Does anyone have any ideas? Is there a better way of fitting the valve than using jubilee clips?

A picture here might be worth 1000 words. Use "Go Advanced" to do it.

If I am following this correctly... go to home improvement store and purchase some stainless steel clamps.. these will allow you to tighten down on hose and valve end more than jubilee clips will... just do not overtighten. Hope this helped!