the aforementioned toilet is now installed and is leaking! It is a BIIO
cistern (actually a B&Q 'Toilet to go' which is a close-coupled cistern)
which leaks into the pan so it's not disastrous. It is not overflowing
through the top of the overflow pipe as that is several cm above the
water level. My best guess is that the flush valve has not seated with
the seal washer and/or lock nut correctly and is leaking that way.
Should I remove the cistern and tighten the valve? (I think I have
tendency to under-tighten such things, due to a fear of
over-tightening!) The cistern does not appear to be leaking externally
at all. The area around where the cistern and pan meet are dry, as is
Is there anything else I should check for? Does anyone know of an
online diagram explaining precisely how these flush valves work?
Suffice it say that the enclosed documentation is of little help.
TIA as ever,
It looks like the seal is leaking. I was able to remove the flush valve
mechanism such that I can now see the connection between the cistern and
the pan and there is a definite leak from the back of the pipe - I can
see the dripping. It's quite a substantial leak and I am wondering if I
simply forgot to tighten up the lock nut at all or whether a bit of
foreign matter is preventing a good seal. The water is not flowing
through the outlet but it coming from 'behind' the seal (if that makes
sense.) If I rotate the overflow bit that's left in the cistern, the
leak moves with it.
Does it have a separate overflow pipe or does it overflow through the top of
the siphon? If the latter, adjust the ball valve so the level is lower & it
should stop. Most modern siphons have built in overflows.
Sounds more like an internal overflow. Any leak between cistern & bowl
usually only happens when the cistern flushes into the toilet.
If lowering the water level doesn't work, it could be where the siphon is
connected into the cistern - the big nut. Buy a tube od Fernox LS-X (B&Q) &
smear liberally around both faces of the big rubber washer, leave for an
Oh what a surprise :-)
Dave - The Medway Handyman
Thanks for the tips. As mentioned in a previous post, the leak does
appear to be at the big nut so I'll try what you suggest. When you say
'leave for an hour' do you mean 'leave for an hour and then re-assemble?'
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.