Hi,

I have recently fitted a bathroom for someone and the toilet I installed was a dual flush close couple. Unfortunately sometimes when it is flushed it makes quite a loud clonking / banging noise and I think it is associated with the mechanism in the syphon dropping down hard. I have looked in the mechanism and can see that there is what appears to be a polystyrene ring inside which I presume should be there, as there was no instruction to remove anything from it. Do I need to adjust the mechanism inside?

Any advice very welcome. Thanks.