PCPaul wrote:

Now that one's sorted, mine is even more weird - same setup *but* with a
traditional lever and syphon. Every so often it trickles water into the
bowl for ages (1/2 hr+) and the only way to stop it is to flush again or
to take the top off the syphon (which is held on with a plastic pin).

It's not an overflow as the cistern doesn't ever fill up, it just flows
straight out again. The syphon doesn't look full so I don't think water
is going up and over.
Any thoughts?

Sounds like a bit of muck, or even a few hairs in the cistern, causing
the seals to be slightly open, allowing a trickle out.
I've had them as well where the siphon is slighlty misaligned, and the
slight twist in it stops the spring pushing the flap down to the seal.
Probably easiest to just fit a new siphon.
Also, do you put those blue tablets in your cistern?
They are known siphon killers, as a blue gunge builds up around the
bottom of the cistern.
Alan.
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