On Nov 17, 4:29*pm, Jeff wrote:
....
The pin hole does not necessarily do the trick - it depends on the
geometry. *On my setup it takes several minutes to release by itself. *I
can pry it with my fingertips after about 15 seconds, but my daughter
can't do it.

Right, it is important that the pin hole is at the top of the intake
line and that the intake is set-up so no water can collect between the
pin hole and the head. If you have a sag in the intake line between
the pin hole and the head it will negate the pin hole and you'll have
to wait for the air to leak into the head through the water and seat
seals. That seems to take minutes. With a proper set-up you you
should be able to open the lid in 15 ish seconds.

FWIW, I met a guy who had taken a regular home toilet and converted it
to a Lavac like system by making a top that could be sealed down when
the toilet seat was up. Seemed to work like a charm.

Sorry for the hurried reply. We're in Ensenada, Mexico and I'm paying
for 'net time.

Cheers to the group,

--Tom.