sm_jamieson wrote:

Yep, I think the crucial thing is that it is actually a syphon, so it
continues with little head of water to maintain it. With our wash-down
pans, water added just pushes out the "stuff" like a normal u-bend,
which is why the new 6 litre things are so feeble.

Some loos in the yookay do have an element of siphonic action -
certainly if the water level in the bowl drops right down and then
recovers, then it is not simply washing-down. Totally agree on the
lack of effectiveness of nearly all low-volume units - not met one yet
which worked first-time, which seems to totally negate the point (a low
volume for pees can be achieved with a two-stage flush system). The
powers-that-be have British Standard turds which they claim flush away
nicely with 23ml or whatever but all I can suggest is that they must
bear no resemblance to proper jobs.

--
"Backup not found: (A)bort (R)etry (P)anic"