I am about to replace the flap valve on a close coupled toilet. I understand it is advisable to use a new doughnut washer. Could anybody please advise me what the purpose of the doughnut washer is, other than to prevent water splashing back from the toilet basin inlet to the underside of the cistern when the cistern discharges. I assume the washer inside the cistern between the syphon and the cistern base should stop water leaks from the cistern itself.
Thanks
Thanks