cistern siphon leak

29 Dec 2006
Reaction score
United Kingdom
Hi Iam trying to fit a new siphon but after fitting every thing back together i have a leak under the cistern it looks like it is coming from where the siphon is fitted thro the cistern, the rubber ring in on the inside as required and is tight . i had this problem with the old siphon and had to seal all round the cistern to stop it . on the instructions for the siphon there is a flushpipe sealing washer and coupling nut but there is nothing for the coupling nut to fit to ? should i have a bit of pipe there ? it is a close coupled cistern. and i have fitted the doughnut would it help if i fitted a rubber washer both sides of the siphon ? thanks for any help. :( John could it be the wrong doughnut can it leak past it ?
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if its close coupled you don't need the flushpipe seal and nut on.
have you tried abit of clear silicone on the rubber washer before fitting in cistern ?

the cistern hasn't got an airline crack has it ?
thanks for reply will remove coupling nut and washer and try sealing on doughnut tomorrow . John
don't seal the do-nut seal the rubber washer on the syphon where it enters the cistern
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i was going to seal both as i dont thing its the leaking past the washer but i will check by filling with water thanks
easy to tell

was it only leaking when you flush?

would have to be bone dry for silicone to take
All done now i sealed every thing that came together with plumbers mate =no leaks .thanks for help

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